Friday 26 October 2012

Cateye Adventure Review: first impressions

Summary


This computer has the same pros and cons as the more common Cateye Strada but with the added feature of an altitude and gradient reading.


Pros


  • Altitude seems to be very accurate and responsive
  • Gradient appears to be good to within +/- 1% (averaged over 50m or so)
  • Batteries last a long time, there is a battery low warning
  • Easy to operate, even in gloves
  • Sensor ID system should reduce or eliminate spurious readings on group rides
  • Good value if bought for the right price (£50)!

Cons


  • There is no way to display both distance and time together or to flick quickly between them.
  • Average speed is shown to only one decimal place which seems mean given that distance is shown to two.
  • Sensor is specific to this model and hard to come by as a spare part.

  • No back light so can't be used at night

  • Selecting mph for speed seems to force the unit to read altitude in feet.

  • Expensive if bought for the recommended retail price (£99.99).

Cateye Strada: My Previous Computer

I recently went looking for an upgrade for my old Cateye computer. I have suffered problems with my old Cateye Strada computer resetting itself, including during this year's (Cambridge to) London to Cambridge ride. The problem was not related to fading batteries (it happens with new ones) but seems to be due to vibration. As the computer gets older it seems to vibrate more and more in the bracket. I tried improving the contact tension on the battery as suggested by one poster on the internet but still had the problem. In the end I used a couple of rubber shims (cut from an old tube) to tighten the fit between computer and bracket. Finally that seemed to resolve the problem but it would have made moving the computer between bikes too fiddly and I'd already resolved to buy a new computer with two sensor kits rather than persevere with the old one. Both solutions are cited in this BikeRadar.com review.

The Adventure Starts

Looking at the latest computer models it seems that the current crop of products falls in to two main categories. Those that are based on GPS and those that are based on the traditional wheel sensor. Clearly some of the GPS-based devices do have support for ANT+ type sensors opening the way for more conventional (and accurate) speed detection. The technology seems attractive and there is surely going to be convergence with mobile phones (some of which already support ANT+) but I've already tried using a phone mount and a GPS-based bike computer app but keeping the screen powered up for more than a couple of hours seems to be a big problem - even with a full charge. Indeed, the downside to all of the GPS type devices is that they need more regular charging and they cost a lot more. So for me, it was back to the traditional design.

The Strada is a pretty basic computer. I've used more sophisticated computers with a cadence sensor in the past but I didn't find that particularly useful past the novelty stage, however I have always been intrigued by the idea of an altimeter integrated into the computer. I imagine that on longer, unfamiliar climbs it might be a useful way of seeing how near the top you are. Curiosity got the better of me and I decided to select the Adventure.

Having resigned myself to the cost of the Adventure I was pleased to see that Amazon were selling it at almost half the price I expected. Unfortunately, I couldn't find anyone who sold the sensor kit for my second bike at anything other than a price higher than the Amazon price for the complete unit so I ended up buying two!

Installation and Set-up

People do complain about the instructions on these computers and I guess they aren't that easy to master. It helps if you've used a simpler Cateye computer before as you'll be familiar the basic way the unit operates. I must admit that I was a bit dismayed to see that the Adventure still uses the hidden button under the unit which you activate by pressing the front of the unit until it clicks. This design seems to require a certain flexibility in the mounting bracket which may be the cause of the vibration that did for my Strada. That said, fitting the bracket and the sensor takes only a few minutes.

Altitude calibration did take a bit or working out. The unit has two altitude figures it uses as a base line, one called 'adjust' and the other 'home'. The idea is that you set the 'home' value to your usual altitude (for me that's 60 feet). The adjust value is there to compensate for the natural variation in atmospheric pressure due to weather. It starts off by displaying the expected altitude (based on a standard model of the atmosphere) but you can adjust it to show the correct altitude at any known point. The computer uses the difference internally to correct the altitude display.

This all sounds a bit fiddly until you realise that you don't need to play with the adjust setting unless you are away from home. If you are starting your ride from your home you only need to press and hold the unit until the adjust screen appears, then press once more to switch to the 'home' setting and finally press and hold again until you are returned to the normal screen showing speed etc. This rather unintuitive sequence of actions sets the 'adjust' value to match your home altitude and can be done without removing the computer from the bracket. This is all you need to do to compensate for changing weather.

Altitude and Gradient in Operation

If you've ever sealed up a plastic bottle during a plane flight and watched it slowly get crushed during your descent you'll know that changes in atmospheric pressure can be quite significant. Although the cabin is pressurised during flight it is not kept at sea-level pressure. Boeing have a nice article on this, apparently the pressure is kept no lower than you'd experience at 8,000 feet. I've noticed the same effect at lower altitudes too. A plastic water bottle closed at 2,500 feet will still appear slightly squashed if you descend to, say, 500 feet.

If you want to know how pressure changes as your altitude changes there are various formulas to help you work it out. There is a handy little calculator at aviation.ch from which you can see that pressure drops by about 1 millibar for each 30ft of ascent at low altitudes. I have a wall-mounted barometer in my house and I can easily detect changes of 0.5 millibars with that (which would translate to an accuracy of 15 feet) but I had no experience of the type of pressure sensors that fit in to small cycle computers until I used the Adventure.

On my first ride I took my bike over some low hills near my home (max height 223 feet according to my survey map). The altitude seemed to be fairly responsive and it briefly read just over 220 feet as I went over the top). The gradient, shown as a percentage, lags the altitude a little. As far as I can tell it is calculated using an averaging process over the last 50 or perhaps 100 meters. As a result you tend to be at the end of a steep section before the gradient starts reading a realistic percentage. You may also find that it keeps reading positive values even though you've started the descent. I still find it useful even though I haven't tried it anywhere with really long or steep climbs yet. When I got back to my house the altimeter was reading 47 feet, a drop of 13ft. This type of inaccuracy is typical with this type of altimeter of course. In this case the pressure was rising at a rate of about 1 millibar every 90 mins so my 45 minute ride coincided with about 0.5 millibars of increased pressure so the altimeter should have read about 15 feet lower - again, I was impressed with the accuracy.

My second ride was longer (about 70 miles) but much flatter. According to the survey map my route touched the 0 contour a couple of times, at those points the reading flipped between 4ft and 8ft. Even bridges with relatively short approaches registered a gradient and a brief increase in altitude up to a realistic looking 20 or perhaps 30ft.

Overall, I'm very impressed with the accuracy of the pressure/altitude reading, it is easily responsive enough and results in a much more accurate altitude reading than the typical GPS-only capability of my phone.

Perhaps the only issue I have had is that the reading on the unit can be a little too reactive. On very flat roads (we have a lot of those near my home) the altitude reading might flip between two adjacent readings sometimes generating brief but spurious sections of 1% gradient. You won't notice this sort of error so much when going uphill but on longer flat rides you may want to be mindful of this when interpreting the total ascent reading.

Other Functions

The Adventure is basically all about adding altitude to the basic Strada computer. With more functions you find yourself having to press the button more times to scroll right through the various display modes. For example, if you are looking at distance and want to change to view elapsed time you have to press 7 times! If you are timing yourself over a fixed distance you'll have to compensate for that in your head.

As a side effect of the altitude function you also get a temperature reading (which I assume is required to accurately calculate altitude from the pressure sensor). In itself the temperature reading is only likely to be useful for spotting icing conditions but as it only shows in the clock mode you are unlikely to see it routinely.

The additional altitude and temperature readings are given in the centre of the display making the overall unit size larger than the Strada. I found the display a bit tricky to read at first (the digit 4 is rendered a bit oddly) but I soon got used to it. There is no back light so forget using this unit at night or in low-light conditions.

Further Reading

You may be interested in the brief review on Bike Radar or this longer review on road.cc.

Wednesday 26 September 2012

The Winter Bike: Up Cane Creek Without a Paddle

As the late UK Summer suddenly turns into Autumn it is time to start thinking about the winter bike.


My winter bike is an old fixie that I had built by Deeside Cycles. The shop appears to still be in business under the name Graham Weigh cycles. My fixie was a Graham Weigh alloy track bike with a road fork and no decals, for that minimalist look. The idea was minimum maintenance, maximum visibility for commuting. I had it painted bright yellow. Ten years on and the frame is looking seriously the worse for wear and the mirage bottom bracket is shot to pieces. Time for an upgrade.


Riding fixed is much more fashionable now and so there's a bit more choice. You don't have to ride a track frame anymore. That said, I'm still surprised how little choice there is if you want to get more generous clearance for mud-guards. I actually had my Graham Weigh frame drilled for mud-guards originally but the clearance is never going to be very good on a pure track frame and I ditched them in favour of a rear splatter guard later.


The whole thing about a winter bike is trying to keep costs down so I couldn't resist going back to steel and the special offers on the Pompino from On-One (aka, Planet-X). I've seen a few of these around Cambridge and someone I used to work with commuted on his and seemed pretty happy with it. On-One will fit headsets for you but when you get an end-of-season discount on a frame it seems like a good excuse to add to the tool collection. The headset press from Cyclus seems like a perfectly good tool for a DIY-er and will pay for itself fairly quickly.


Sticking with the 'cheap and cheerful' theme I bought a Cane Creek S2 headset. As the inventor of the AHead design, what could possibly go wrong? The supplier will remain nameless (I didn't buy it from On-One themselves) at this point as I haven't given them a chance to comment on the problems I had!


Although lots of online stores offer the S2 for sale the S-type headsets don't seem to be documented on Cane Creek's website. It looks a bit like they've had a make-over as the legacy product area is a bit thin. Fortunately, the old site is accessible through archive.org. The S2 page contains a useful diagram of the headset and the manual is still available too.




See the full size image on archive.org.

It is lucky that these sources are still around because when the headset arrived it was just a collection of bits in a poly bag. No instructions or diagram to check the bits off against. It looked like everything was there, the supplier had even packed an extra compression ring for some reason.


When I fitted the cups to the frame I must confess I thought it was odd that the two cups where identical and that, as a result, the logo on the top cup would be upside down. Manufacturers are normally rather vain about this sort of thing. But, the design of the S2 includes a top cap that fits over the upper head-tube cup completely. So the upside down logo is obscured when the headset is assembled. Having the two cups the same would certainly reduce the chances of people installing the cups the wrong way round. That must be it. I installed them.


Except, the cups are not supposed to be the same. If I'd looked more closely at the diagram I would have seen that the lower cup is supposed to be a bit deeper than the upper cup so that it comes down over the rubber seal on the crown. I didn't notice this and proceeded to build the bike. When I came to pre-load the headset by tightening the top-cap I just couldn't get the bearings to load properly. Either it was stiff and noisy or it was too loose.


It was only then that I started poking around on the web and realised from a few image search results that the upper cup should not have a printed logo at all. I'd been shipped two lower cups. I'm not sure if the diagram on the old Cane Creek site is really to scale but a bit of image editing shows the problem area. The longer cup comes too close to the top cap. Sure enough, before the bearings are properly loaded the top cap was starting to rub on the cup. This was confirmed by tightening the top-cap until the headset felt stable and then turning the handle bars. The top cap was sticking to the cup, instead of turning with the steerer and the spacers which are pressed against it.



I've edited and exploded a detail from the diagram to show how it should be (on the left) and how it turned out (on the right).


A Stroke of Luck


The next day my son took delivery of a freewheel and in the packet were a couple of 0.3mm spacers. As luck would have it they were exactly the right size to fit on a 1 1/8" steerer. I guess a proper 1mm spacer would have done the trick too but I didn't have a spare and it was a Sunday, not a great day for buying such a specialist part.


I fitted the two spacers just below the top-cap so that they sit on top of the compression ring. They provide just enough extra stack-height on the bearings to keep the top-cap away from the cup. The whole thing now works perfectly.


I do intend to take this up with the supplier but the hassle of removing the cups to send them back would have just meant delays. Also, I don't yet have a proper tool to remove headset cups and I'm not sure what I could improvise with. I know, I could just take it to my LBS and admit defeat but half the fun of buying cheap stuff online is getting yourself into, and out of, scrapes like this.






Wednesday 12 September 2012

Stripping My Old Frame: Removing a Stuck Octalink Bottom Bracket

My old Tifosi bike was fitted with 105 equipment. I've recently replaced the bike with a completely new home build after many thousands of trouble-free riding miles (see previous blog posts about that project). But I still have a fondness for the Tifosi frame so last weekend I set about stripping it down so that I could consider its future properly.


After almost 8 years of use and many thousands of miles without a complete strip-down and rebuild it was certainly possible that some of the components may be a bit hard to shift.


Carbon forks and 105 callipers: written off


I'm a bit gutted that my carbon fork and 105 brake callipers have simply been trashed by so many years, quite literally, in the front line against the British weather. Removing the securing nut from the back of the fork was stiffer than I'd expected. The exposed bolt has fused with the nut so when I removed the nut half the bolt came away with it. Unfortunately, it gets worse. It turns out that the alloy crown on the fork has corroded badly too and bonded to the brake calliper itself. I could get the drill out and start trying to remove the bolt from the crown but there's no point because the nut needs a surface at the back of the crown to tighten against and this has completely disappeared in a puff of white aluminium oxide. From now on I'm going to remove the front brake (from my other bikes) and re-grease at least once a year.


Crank Removal


The Shimano Octalink system replaces the traditional square-tapered spindle with a hollow spindle with eight splines that fit snuggly in the crank arms.


Despite so many years uninterrupted use removing the cranks was fairly straightforward once I had the right tool. My crank puller was designed for square tapered cranks. The puller really works by holding the crank still and pushing the spindle (and the rest of the bike) away from you. To do this it needs a firm surface on the spindle to push against. For square tapered cranks there is plenty to push against but the Octalink presents a very small lip (this is the older first generation Octalink system). To engage with this you need a specially designed crank puller or an adapter tool from Shimano. I've seen tips on the internet about using various coins to do this but I have quite a collection of British, European and US change and I wasn't happy with the fit on any of these coins. My local bike shop had the required adapter which made the job easy.


Bottom Bracket Removal


The real challenge came when I tried to remove the bottom bracket. Removing the non-drive side is easy because it is just a small plastic sleeve. The drive side actually contains the spindle, bearings and the housing and was firmly stuck in the frame.


Years ago a bike mechanic I used to use would weld the spindle to the bottom bracket shell and then reattach the crank and use that as a lever in this situation but that trick only works on the (even) older loose bearing types. However, for any type of job that required use of an extractor tool he would always place the tool in a vise and use the bike (or wheel) as the lever.


Even with the vise trick, getting the extractor tool to keep its grip while I applied the leverage was still a problem. Various people suggested using a skewer or other long bolt to clamp the extractor to the bottom bracket. I could not get this to sit securely with my tool which has a wide open end but I did hit on a slightly simpler solution. I used one of those cheap spanners you get in portable tool sets and the orignal crank bolt to clamp the extractor.



Finally I was able to securely apply the leverage I needed to remove the bottom bracket!






Sunday 19 August 2012

Campagnolo Centaur: 1,000 mile review

During May I wrote up some of the tricky bits of my home-build Cinelli Saetta/Centaur 10-speed. You can review these posts in the May archive.


Since I originally put the bike together I've managed around 1,200 miles which is plenty of time to discover most of the issues with the Centaur groupset. Before this build I was using an ageing set of Shimano 105 9-speed kit. Comparisons across Shimano and Campagnolo can get emotional at the best of times and the developments over the last 10 years would make it a bit meaningless. But moving from 9-speed to 10-speed certainly requires a significant step forward in the precision required during the build.


The 'H' Screw


The Campagnolo instructions for the rear derailleur contain a section on adjusting the 'H' screw. Out of the box mine was a bit tight, the gap to the largest sprocket - 25T - was less than the required 7mm. Measuring and adjusting this is a bit tricky, I recommend cutting a 7mm piece of card similar to the one I used when determining the length of the chain.


If you don't get this one right then the chain will need to turn too tightly as it feeds from the upper jockey-wheel of the derailleur to the sprocket. The result is a noisy drivetrain.


Vertical Derailleur Alignment


Despite getting the 'H' screw right I was still having difficulty getting the drivetrain to run as smoothly as I would like. I suspected a problem with derailleur alignment but I rode the first 500 miles trying to find just the right combination of cable tension, 'B' and 'G' screw positions.


I finally realised the something needed to be done when I heard a strange ticking from the chain when I was in the smallest sprocket. After a bit of detective work I realised that this was the sound of the joining rivet striking the inner face of the derailleur hanger. It is a bit hard to visualise but I've done my best to take some pictures:



I've circled the special joining rivet in the two pictures which show that it protrudes enough to strike the hanger.


The first thing I did was adjust the 'B' screw on the assumption that the derailleur must be moving too far out when on the smallest sprocket but even the smallest change resulted in a poor change on to this sprocket.


I also wondered if I had really got this chain joined correctly. I was careful to measure the protrusion on the inner plate with a micrometer to ensure it was as close to the designated 0.1mm as I could get it. This results in a larger protrusion on the outer face of the chain. This is all according to the instructions - the following picture shows this protrusion:



The chain manual comes with the following warning, which makes it pretty clear that I shouldn't consider altering the chain:


The slight protrusion (X) (towards the external side of the chain) of the small pin (E) from the link (Fig. 17) is entirely normal and does not obstruct normal chain movement. NEVER try to eliminate this protrusion.


By a process of elimination the problem must lie with the alignment of the hanger itself. In my 9-speed 105 days I could get things running smoothly again with a simple running repair - aligning the cage by eye while being careful not to actually bend the cage itself. With the Centaur 10-speed this is no longer an option. It is very hard to spot when the cage is off by a small amount but it makes all the difference.


So I stumped up for a proper alignment tool from Park. This really is a good tool, easy to use and really solid feeling. Unlike the comically aligned derailleur on the Park Took help page mine was a bit out of true on the vertical and a bit twisted - this was a brand new frame with a separate hanger but I guess these things are easily damaged in transit or simply don't come straight in the first place.


Correcting these faults and readjusting the gears resulted in that smooth as silk feeling you'd expect from £500+ groupset.


Slipping Brifters


I did have just a couple of other niggles during my first 1000 miles with the Centaur groupset. At one point, during a bumpy descent, the cable tension on the rear derailleur seemed to go completely wrong. I ended up fiddling with the barrel adjuster on the road but I couldn't get it right again.


It took me ages to notice that what had happened was that the brifter had a slipped a tiny amount on the bar. The cables where taped firmly to the bar under the handlebar tape so the result was that the tension increased a little on the cable as a tiny gap had opened between the end of the cable cover and the cable stop in the base of the brifter (all unseen under the covers).


Sticky Cables


The final issue I've had seemed to be heat related. England had a particularly cool (and rainy) spring/summer but the hot weather has finally arrived now and this seems to have been responsible for a few problems with increased friction between the gear cables and the plastic cable guides on the frame. It may just have been the grease drying out too quickly or perhaps the heat softened the plastic a bit and allowed the cable to cut in a little. Either way, the problem was fixed by slackening off the cable and re-greasing.


Conclusion


The Centaur 10-speed groupset sounds smooth and the change is nice and crisp. The ability to multi-shift when changing to the larger sprockets is useful, especially after you've just changed up to the big ring. For me, the big selling point is the position and ease of operation. My short fingers can change up a sprocket (or maybe even two) using the Centaur's lever without difficulty even when on the drops. This is a big change for me and for the first few hundred miles I found myself bringing my hands up on to the covers out of habit, the Shimano system of pushing the whole brake lever was always too much of a stretch for me from the drops.


Although some people complain about the position of the button for dropping to the smaller cogs I can reach it from the drops without too much of a stretch. Of course, I did have the luxury of fitting them exactly to my preferences!


On the negative side, the brifters seem a little light and flimsy. Light is a good thing of course and I'm probably just out of date - my 105 levers felt more robust but they also weighed a lot more. On the few times I have had problems with the Centaur gear-change the levers and, in some cases, the shift button have gone very stiff and I felt like I've had to treat them carefully to prevent accidental and expensive damage.


More significantly, the 10-speed drivetrain is very particular about adjustment. The extra sprocket seems to come at the expense of significantly more tinkering time. Although this was a home build project the real fun comes from riding the bike. After 1,200 miles I really seem to have found the sweet spot but it's already time to start checking for chain wear. I'm a light rider riding 165mm cranks in a fairly flat part of the country so hopefully I'll be able to squeeze a few more miles out of the Centaur chain before I need to replace it.



Tuesday 24 July 2012

London to Cambridge, not to mention Wiggins and Cavendish

In 1986 I worked in a local warehouse until I had enough money to buy a proper bike and then set off around the south coast of England. At Land's End I met a lot of people who were about to start their 'End-to-End'. There were a lot of worried faces because the prevailing south-westerlies that would normally blow them out of the west country and up towards Scotland had been replaced with severe north-easterly gales - a sort of aftershock from a recent Atlantic Hurricane. Anyway, I set off through torrential rain and rode slowly up the coast road to St Ives at which point the wind got strong but, mercifully, the rain stopped. I decided to dry off in the laundrette and struck up a conversation with a local elderly man. We discussed the difficulty of the weather and it turned out that he was a keen cyclist. "You don't see many lone cyclists these days" he commented, with clear approval of my solo riding habit.

How things change, cycling is a lot more popular in 2012 and I often see solo cyclists out on the road. But this popularity contrasts with a similar rise in the popularity of mass participation cycling events. The web seems to have a blind spot for the history of the London To Cambridge bike ride though it seems likely that it started after the London to Brighton as there has been such a long tradition of holding events (not just bike events) between those two cities. That event even has its own wikipedia page and it appears to have been running since 1976 - judging by this article and accompanying poster. It must have been held during one of the UK's most famous droughts. These days, around 30,000 people participate in that annual ride. According to one report Sunday's London to Cambridge ride had 5,000 participants. The official site makes the more modest claim of "around 4,000". Either way, I had no idea these events were so popular.

Out and Back


So in all innocence, on Thursday night I decided to sign up online for the 2012 London to Cambridge. The plan was to rise early, cycle gently down to the start thus ensuring there was plenty left in the legs for the return journey. This would also be the first time I'd be riding my new Cinelli bike over 100 miles in a single ride - a chance to find out if the frame is forgiving enough to remain comfortable over longer distances.

I did wonder if I'd see other riders on my way down to London but I didn't expect it within 5 miles! I rode the remaining 42 miles to the start with Simon and Chris who are veterans of this event and have clearly paced each other over many miles together. Despite this experience we did take a wrong turn in the last few miles and ended up riding against the flow of the event to get back to the start. At this point, it really brought home to me just how many people participate.

The event has been in the hands of bike-events.com for many years so, as you might imagine, the organisation is very slick. It wasn't long before I was on my way with that unfamiliar feeling of having a number pinned to my shirt.


With so many riders on the road it was a case of move at the pace of the group on the flat but as soon as the road started to climb the riders started to bunch up and I found myself in the fast lane. At the top of the first climb I saw Chris and Simon up ahead but I quickly realised that experience counts for a lot when you are cutting through the traffic and they disappeared off into the distance.

Official photo thanks to  

After about 10 miles things started to settle down a bit, riders were getting stretched out a bit more and I found myself mainly surrounded by people of a similar pace. There were still a few hares who come racing past on the flat (or the descents) only to slow to a tortoise pace on the next climb. Hats off to the guy on an old black Cinelli Gazetta track bike though: any lack of speed on the climbs was more than made up for in style.



This event clearly has a significant impact on motorists who are used to travelling much faster. It is almost impossible to overtake the riders once you get in amongst them (there are just too many). Hopefully most were successfully warned and managed to avoid the route completely as the roads were de facto closed, at least in the direction of travel. When cars did get on to the course they tended to have to move at the speed of the slowest and this resulted in serious bunching of the riders behind them - especially on the hills. It is a shame that a tiny minority of riders show a lack of patience in this situation and end up doing risky overtaking manoeuvres because this is exactly the sort of thing that upsets cyclists when the situation is reversed. Still, despite all the talk of road-wars in the press it really is a tiny minority of people (whether on two wheels or four) who show their frustration. My top tip for these events: best to just ignore the average speed on your cycle computer and enjoy the ride.




The route seems to be chosen more for the practicality of minimising the impact of traffic than for taking in particular climbs. The above picture shows the total elevation profile of my ride (created with MapMyRide). The left-hand side is the southward journey to London via the hill at Barkway. As you can see from the right half of the picture the official route has the typical saw-tooth profile of a ride through England's rolling landscape but there are no long climbs and the maximum elevation is never more than about 450 feet. MapMyRide has a climb classification system but it fails to register for this route - there are a few steep bits but they're way too short to show up on this sort of system.

Sadly the last bit of the ride directs people through the centre of Cambridge which is notorious for its traffic. Yesterday was no different - stationary cars for the last 2 or 3 miles on roads with no reserved space for cycles. Cambridge prides itself on its cycling credentials but visiting Londoners must have wondered why.

The ride finishes on Midsummer Common which gives it something of a summer fair feel and provides a way for a non-cycling spouse to share in the occasion. The weather was perfect for resting on the grass and replenishing energy supplies from the various catering vans. I must also mention the commentator who started the riders off in London with a carefree "be off with you" and was transported to Cambridge in time to welcome them to the common with various comments ranging from the sartorial to the frankly bizarre. He certainly brightened the afternoon and made it a bit less boring for the people waiting for their friends and relatives to arrive.

Hats off to Cavendish and Wiggins!


With such an early start I had plenty of time to eat lunch on the common and peddle slowly back to my house in time to watch the end of the Tour de France. It was a tense last lap of the Champs Élysées but the finish, with Bradley Wiggins in yellow leading out Mark Cavendish to win the stage completed a fairy-tale ending for British riders in the Tour. I know that there seems to be a huge gap between these super-elite athletes and the people who participated in the London to Cambridge but to me they are still connected. Sport is like a pyramid, if you want to build it high you have to start with a wide base. The fact that British riders have won the Green Jersey and then the Yellow Jersey in consecutive years when no British rider has ever won either of these competitions before is not just a stimulus for future riders, it is also indicative of the growing interest over the last 20 years. Who knows, perhaps some of the younger riders who took part on Sunday only to realise that they could keep up with the fastest riders might now think of taking up cycling as a sport too.

"Just ride and be happy"


So am I a convert to mass participation events? Would I consider doing the London to Brighton for example? It is a similar distance to the London To Cambridge (though with more climbing) and it might just be possible to start the ride in Cambridge, thread my way through central London and still have enough in the tank to get up the Beacon at the end. Or do I feel like Matt Seaton whose quote I've borrowed for the sub-heading. He said on the Guardian Bike Blog:

I often get asked: "Oh, have you done the London-to-Brighton ride?" To which my answer is, no, I've never done it – because it means sharing the road with 30,000 other cyclists and no one can even ride up Ditchling Beacon (the big hill behind Brighton, and the best bit) because of all the folk pushing their bikes. OK, so that's a tad snobby, but I do ride to Brighton (and back) at least a couple of times a year

I'm sympathetic with much of what he says in that post but, like him, I've ridden solo to London (and back) several times for pleasure and yet this time there was the added sense of occasion that the event organisers are so good at generating. For me, it certainly isn't about the charity sponsorship. I don't need that motivation to ride my bike (or to give to charity).

I think my enjoyment at doing the London to Cambridge stems mainly from the fact that the Cambridge end is home. One of our biggest local companies, ARM (and I'm talking as a resident of Cherry Hinton here) had over 100 riders taking part. I also saw plenty of riders from the other big local name, the Marshalls engineering group. If I did London to Brighton I wouldn't feel the same connection and I'd have the added inconvenience of having 7 times less room between me and the person in front.

Would I do London to Cambridge again? Yes, definitely - the out and back route combines the advantages of both solo and mass participation riding. But keeping this type of thing as an annual event feels about right to me.

Monday 16 July 2012

The Build Part IV: It's a wrap!

This is the final post in what turned out to be a four-part series.  In the last part I got the chain fitted, all that remained was for me to check the position of the brifters and handle bars before taping up and make those last minute adjustments to the gears that are inevitably necessary.


I did have one little niggle with the front derailleur adjustment before I could close out the build.  When I first connected the cable to the front derailleur I had an issue with a bit of poor alignment in the lever body.  The outer body of the lever has a hole through which you feed the cable for the gears, this is supposed to line up with a hole on the inner body but mine were misaligned and the gear-cable end caught at the interface.  I pulled the cable tight from the other side and didn't notice until I came to adjust the front derailleur - it was clear something was wrong but it took some searching to identify this as the problem.


With the cables connected and adjusted and the rain stopping I took the bike for a quick spin around the block to check I was happy with the position of the levers and the tilt of the bar.  Sadly, with a strong wind blowing up the nearest gradient it was impossible to really get out of the saddle to get the feel for the position.  Also, the rain only stopped for about 20 minutes before the weather closed in so I did a few tweaks and then had to run inside before I got drenched.


Still, impatient to finish the job I turned to the last task: taping up the bars.  The wintry weather had given me plenty of time to read up on this task.  Here are my three main picks for a description of how to do this job...


Installing Handlebar Tape - Sheldon Brown


This one had to be top of my list because, on a Cinelli frame with a Cinelli bar it simply has to be Cinelli cork handlebar tape to finish the job. The author even describes himself as "Sheldon 'corker' Brown" here so he is clearly aiming the article at people like me. Sadly, the article is incomplete. It is possible to get a few glimpses of his approach though.


The key to a reliable taping job is tension. As you wind the tape onto the bars, you should hold it under constant tension, never letting it go slack. The amount of tension should be quite considerable, enough that you might actually worry about breaking the tape

and on the important issue of winding direction:


Generally, handlebar tape should be wound on starting at the ends of the bars and winding toward the middle....

...I generally start from the underside of the bar, with the tape feeding outwards. You can do it the other way too, but make sure you follow the same pattern on both sides.

Handlebar Tape Installation (drop bar) - ParkTool.com


In general, you can do a lot worse than following ParkTool's advice on most matters I find. Perhaps the most accurate advice on the internet...


Handlebar wrapping is a skill that takes practice and patience.

This bike build introduced to me to a lot of new tools and components but in most cases using the right tool, following the instructions and using the correct tension when tightening fasteners means that no particular skill was required. Sure, it took me much longer than an experienced bike mechanic but the results have been similar up to this point.


On the issue of winding direction ParkTool's blog is more definitive:


Looking from the rider's point of view (from the back of the bike) wrap each side the tape rotates inward from the top. In other words, wrap the right bar counter-clockwise and the left bar clockwise.

How To - Handlebar tape - Sprinta Della Casa


My final pick is the more quirky Sprinta Della Casa. This article goes into a little more detail. It's less emphatic about the correct winding direction:


I wrap from the inside, over the bar. If you do it the other way it's up to you, but I've found the "over" direction works well.

This is the opposite of Sheldon Brown's preference and ParkTool's recommendation which suggests to me that it probably doesn't matter that much. I like this article for the conversational style and the number of pictures.


In conclusion, the golden rules seem to be:


  1. Clean hands
  2. Tools within easy reach (so you don't have to let go)
  3. Wind from the bar end towards the centre

My first attempt


Sadly, my first attempt was not very successful. It is a long time since I wrapped my bars and I'd never used the Cinelli tape before. I was worried about breaking it and didn't pull hard enough to get a snug fit. I was also using the Gel variant of the Cinelli tape which has two adhesive stripes rather than a single central strip. This reduced the traction on the bar during the job and meant that a couple of times, where I'd broken golden rule number 2, the tape started to unwind.


After the first half of the bar was done I had more tape left over than I expected - I could have increased the overlap, particularly around the tight parts of the bend. I did the second half of the bar better and when I finished the job the tape looked fine but I could have usefully gone back and re-wrapped that first bar with hindsight.


The result, after 500 miles the tape was already coming loose. After 750 miles I gave up and rewrapped. That gave me an opportunity to change the colour of the tape too (on reflection, the white looks better than the blue).


In summary, I'd add a fourth golden rule to the three above. If this is your first time with a particular type of tape:


  • Buy two lots of tape, that way, if you mess up you have some spare tape to help you finish the job properly.

Shake Down


With the bar wrapped and a small break in the the weather a few days later I was able to finally take the bike for a shake down ride one evening. The only problem I had was a consequence of the problem I described with the gear cable on the left brifter (the cable that connects to the front derailleur). Clearly the last minute adjustments to fix the cable tension problem (see above) had screwed something up.


I was just starting to ascend one of our local climbs (or what passes for a climb in our area) but the Centaur's release button was jammed and wouldn't drop the chain onto the small ring. Fortunately it wasn't too steep and I could use the right-hand lever to get comfortable. I figured that, for the button to jam, there must be some unwanted tension in the system. I loosened the barrel adjuster as much as I could (by screwing it into the frame lug as far as it would go - being mindful not to put my fingers through the spokes of the front wheel). This seemed to do the trick and the button could then be pressed and the chain shifted down. Of course, at this point there wasn't enough tension in the cable to shift back up. After a bit of fiddling I found an adjustment point that seemed to work enough to get me home but the whole thing had to be redone from scratch. That is, I had to remove all the tension from the cable, remove it from the clamp on the derailleur, reset the barrel adjuster (by screwing it in) and then reattach and tension the cable as per the instructions.


What happened? I'm not 100% sure. It seems likely that the cable had become too loose (as these things don't usually get tighter by themselves) and that I had pushed the level too far beyond the third click at the previous up-shift (the lever itself also appeared to be jammed). Either way, the levers feel a little more fragile than then old 105s I'm used to - a result of their lighter weight I expect. They're also quite expensive so I was pleased to get through this glitch without the need for more expensive spare sparts.



Saturday 19 May 2012

The Build Part III: How long is a bike chain?

Following on from the first two parts of the build project, in this part I finally connect up the cranks to the sprockets and get the derailleurs adjusted.  With combined 'brifters' it makes sense to cable up and adjust the brakes too, just in case the temptation to get on and pedal is too much!

Before the chain can be installed, it needs to be cut to the correct length.  For my build I'm using Campagnolo's Centaur groupset and hence the 10-speed, ultra-narrow Centaur chain.  Prior to the installation I did a bit of research on chain sizing.  Remarkably all bicycle chains come in the same pitch (the distance from one roller to the next) and this is set at 1/2" (half-inch).  Given the bewildering variation in almost every other aspect of the drivetrain, resulting in incompatibility between components from different suppliers, I'm surprised that chain-pitch has remained so constant.  Anyway, this means my 114 link Centaur chain is 57 inches long.

Replacing an existing chain is easy, you just count the links and make the new one the same size.  You have to be careful not to just measure the length because a worn out chain will have stretched a bit and you might end up with an extra inch or two on the new chain.  But with a new build you need a different method.

Chain Length Sizing - Park Tool


Given that I recently bought a Park Master Chain Tool (more below) I thought I'd start at Park's excellent pages aimed at the DIY mechanic.  They outline two methods of sizing the chain for a new build.  The first involves measuring the chain against the two largest cogs without threading it through the rear derailleur and then adding one inch (two links) to compensate.  Their second method is similar but uses a calculator instead, in other words, you put the size (in teeth) of the largest chainring and sprocket into an equation along with the distance from bottom bracket to rear axle.

From the formula they give I put in the distance to the rear axle (16 1/8 inches), my 50T chainring and 25T sprocket and, finally, the additional 1 inch to compensate for the derailleur.  The result is a 52 inch chain.

Chain Length - Sheldon Brown


Sheldon Brown deals with chain length in a longer article on derailleur adjustment.  He uses the same method, in essence, resulting in a chain 1 inch longer than the minimum required to run the large/large combination of chainring and sprocket.  He does hint at a possible reason for this algorithm being the accepted norm: a chain that is too short will cause damage whereas a chain that is too long will only affect gears that you shouldn't be using anyway.

(StackExchange: Setting Chain Length)


The accepted answer on StackExchange simply cites Sheldon Brown, but at the time of writing there is a comment from one of the moderators to the effect that you should allow 2 links (in this case meaning 2 inches I assume from the context) for Shimano.

WikiBooks: Read Derailleur Adjustment


While researching this topic I found another new source of information I didn't know about, there is a wiki book on Bicycles with a detailed section on Maintenance and Repair.  Again, the conventional wisdom is big/big + 1 inch.

Campagnolo Method (pdf)


With all this general advice to be around the large/large method I was surprised when I unpacked my Centaur 10-speed chain and found a completely different method of chain length sizing.  Whereas most people advocate a method which results in the shortest possible chain that can work (on the large/large combination) the Campy method is a small/small based method which results in the longest possible chain than can work without rubbing the derailleur.

The basic idea is to draw the chain tight enough to ensure a small gap at the point where the chain is at its closest approach.  This is the part of the chain feeding in to the lower jockey wheel.  When the derailleur is retracted to take up the slack the lower jockey wheel bends back and upwards reducing the gap to the part of the chain going around the upper jockey wheel to a minimum.  The instructions suggest setting this gap at a maximum of 10-15mm.

To make it easier to follow this method I cut a small piece of card diagonally, 15mm at one end and 10mm at the other:


The result of using this method was that I needed to remove 3 inches (6 links) from the chain.  That makes it a 108 link/54 inch chain, two inches longer than the chain predicted by the equation above.  I think there are several reasons for this difference.  Firstly, I could have stuck with the 34T chain ring that came with the crankset and that might have meant knocking out one more pair of links (taking me down to 53 inches) - which is within an inch of the length predicted by the equation.  And anyway, perhaps these new Centaur 10-speed derailleurs require 2 extra inches, rather than the 1 inch given in the formula.
   
In all of my internet searches (on a range of topics) I quite often got results from the blogger "Sprinter Della Casa" and he is the only one I found who seems to espouse the method of using the longer chain method.  I'm not sure about the rationale but I enjoyed the article: How To - Campy Chain Install, Illustrated.

The Mystery of the Missing Bearing


Installing these new chains always makes me a bit nervous.  Each time the technology is updated the tools become more specialised and the margin for error is reduced.  The Campy tool shown in the illustrated How-To above is obviously the right tool for the job but Park do make a more general purpose tool that might be more useful when working on other bikes too.  Not to mention being cheaper.

Park clearly have a good reputation and other tools I have from them have been flawless but this time they let me down, at least initially.  I had just started breaking the chain to remove the extra 3 inches when I heard an alarming and very audible popping sound.  I examined the tool and the chain and I couldn't see any signs of damage or anything that could have made the noise so I continued pushing the pin through until the handle on the chain tool would go no further.  At this point it was clear something was wrong because the roller had not been pushed all the way out of the link.

The design of the tool is for the pin to sit on a small bearing in the barrel of the tool.  The pin and bearing are held in place with a retaining nut so that they can be changed should the pin become worn or break.

So I unscrewed the retaining nut intending to take the pin out for a closer look.  The pin was stuck fast in the body of the tool.  Now I figured that if the pin didn't protrude from the tool far enough to drive the roller out of the chain then the bearing that should be in there is missing.  Sure enough, it came up short by what would have been the width of the bearing.  I returned the tool for a warranty replacement and got a replacement from the supplier pretty quickly.

This time I checked that the pin and bearing were present.  They were, and I noticed just how snuggly the pin sits in the tool, as you load the pin and bearing into the barrel you can feel the air trapped in the barrel pushing back against the pin.  You have to push it slowly in, giving time for the air to escape around the pin.  My theory is that the bearing was missing originally and that the final part of the barrel is an even tighter fit - as I turned the handle the pressure built up in the barrel until the air popped out, allowing the pin to jam itself in the barrel for good.


  











Saturday 12 May 2012

The Build Part II: Ergo Brifters: under the hood

In The Build Part I, I covered my experiences with installing the Power Torque Campagnolo cranks.  Attaching the other bits of the Centaur groupset to the bike looks pretty straightforward in comparison.

The Saetta frame comes with a 'braze-on' clamp for fixing the front derailleur and the hanger for the rear derailleur was already attached.  The frame was actually shipped with a spare hanger - useful if you come off on a right-hand bend and squash the derailleur in towards the back wheel.  In the past I've had to do this as a running repair but with the precise alignment required for the 10 speed system it looks like the accuracy needs to be more than just by eye.  So that spare hanger may come in handy - in the UK we have a lot of roundabouts and we go around them clockwise which must increase the risk of this sort of accident.

The hardest part of fixing the rear derailleur was tightening the fixing bolt to the correct torque.  The bolt head is recessed in a narrow channel that will not allow me to put the hex socket in so I had to do it by feel with a regular Allen Key.

The Centaur brakes appear identical in the box and it is hard to see, on first look, which is the front and which is the back.  The difference is so obvious to the experienced bike mechanic that it seems not to warrant a mention in the instructions.  I'm glad to see I'm not the only one who felt the need to consult the internet to make sure, as evidenced by this bike forum post.  The answer is of course that the front brake has a longer bolt to allow it to pass through the fork.  Given that fork widths vary, and carbon forks tend to be a bit fat at this point, you may need to get a longer nut to make contact with the brake bolt.  Both Campagnolo and Cinelli thought of this and I had multiple sizes shipped with the brakes and the correct size bolt shipped with the frameset - another item for the spares box but all good.

If I thought the rest of the job would go really quickly I was wrong.  The next step is to put the Ergo levers on the bars and connect them up to the derailleurs (you need to do this before you put the chain on because you are going to need to operate the derailleurs as part of the chain installation procedure - more on that next time).  It is always nice to learn a new word (especially one that dictionary.com doesn't know about yet) and I soon discovered that a 'brifter', far from being the long lost relative of the old Raleigh Grifter, was in fact a common synonym on the internet for 'lever' in this context; being a simple contraction of brake/shifter.

The instruction leaflet that comes with the Campagnolo brifters merely says "Raise the support cover to expose the securing screw" and shows a picture which appears to show the base of the rubber hood being peeled back (as it will be when you install the bar tape) far enough to get a clean line of sight into the head of the bolt which turns out to be a T25 torx head and not a plain hex.  I believe this is impossible.  I would not want to attempt this in a cool environment as I felt I needed all the warmth of my house, combined with the warmth of my hands to make the rubber supple enough to peel easily without tearing but try as I might I could not expose the bolt as shown in the diagram.

I'm not the only one, there are numerous threads in bike discussion forums where people are having trouble with this point.  My favourite is this one, which is a little old now but the technology and the lever shapes are basically the same: Campagnolo Ultra-Shift Mounting Bolt (or: stripping is awesome).  This thread makes a couple of important points.

(1) Don't try and get in from the base of the hood, instead, go in from the top of the hood.  I love this report in the above thread from someone who sought official advice: "The man with whom I spoke at Campy, however, advised instead pulling up the hood from the top of the lever and pushing it back toward the base (i.e., entirely opposite from what the instructions say)".

(2) Even with the hood completely clear of the bolt it may be impossible to get a straight line down to the bolt head for a torque wrench and you risk stripping the soft alloy bolt if you apply too much force this way.  Another quote from the above thread: "I wrestled with the hoods and managed to get enough clearance so that I could get the wrench in straight (or as straight as you can given the placement of the bolt on the body), but I still had that trouble".

There is now an excellent article on BikeRadar.com on How to Fit Campagnolo Ergo Levers.  It shows the solution to (1) and has a fabulous photo of the small rubber 'nib' being removed before the hood is peeled back from the top.  Here is my feeble attempt at a similar picture:

The left-hand lever showing a narrow screw driver head inserted through the lever to free the nib
Close up of the screw driver being used to push the rubber nib back into place
The BikeRadar article also clearly shows the extension on the torque wrench allowing the mechanic to get a straight line into the bolt head.  On my levers this was just not possible because the position and angle of the bolt caused the extension to foul the top of the lever.  So I didn't tighten it up this way because I was concerned about stripping the bolt head.  Instead, I went out to the local auto-parts store and bought a set of Torx-keys (assuming that's what you call something that looks like an Allen key but has Torx heads instead of a plain hex).  I was able to get the short end of the T25 wrench into the bolt head nice and squarely and therefore I could tighten up the bolt enough to prevent slippage, albeit by feel again.  It was still a tight fit, as this picture (this time of the right lever!) illustrates:

T25 wrench inserted under the hood to tighten the clamp bolt



Saturday 5 May 2012

The Build Part I: Power-Torque cranks

So to recap, I have bought my Cinelli Saetta frame and fork through my local bike shop, Howes.  The frame-set comes with its own Columbus headset and Cinelli-branded seat clamp.  My local bike shop fitted them all together for me with the Vai Bianca stem.  The next step for me was to protect the frame with pipe insulation (to prevent knocks during the build) and then fit the saddle and seat post.  I have hooks set up which allow me to suspend my bikes by stem and saddle so fitting these allows me to use the hooks as a work stand.

This seems like an excellent opportunity to introduce an emerging source of information on bike maintenance: bicycles.stackexchange.com.  People who work in the IT industry will be familiar with programmers' Q&A site StackOverflow.  There is a brief wikipedia page on the history of this site.  The stack exchange concept takes the success of this original idea and attempts to stamp it out across a wide range of topics.  The stack exchange on the subject of bicycles seems to be well populated with content.  I put this down to common elements between the mentality of the DIY-bike mechanic and the mentality of the programmer.  So if you are attempting to apply experience gained fiddling with computers to the more mechanical realm of fiddling with bicycles this site will probably be speaking your language.

It seems that my ceiling hooks have saved me from the dilemma of working on a carbon bike using a traditional work stand.  To summarise this thread from stackexchange, if in doubt don't do it and whatever you do don't do up the clamp too tightly!

In my last post, Cranky Delays..., I discussed my choice of gears and chain rings.  Installing the cranks seemed like a sensible first step but as I worked on the bike from my eye-level hooks I did realise that there was a better way to work on the cranks when you need to tighten things up - just add wheels!  It seemed much easier and more natural to applying the forces required to install the crank set with the bike on the ground with wheels and tyres fitted.  I guess it does depend how far from the ground you are.

I've installed a few square-tapered bottom-brackets over the years but the new breed of cranksets with their outboard cups and hollow axles are a completely new experience for me.  The instructions that come with the crankset are pretty scary, emphasising the need to face the bottom bracket before installation.  I actually checked back with the frame dealer before proceeding but they reassured me that the shell was ready to take the new cups and my measurement of the shell width came in at 67.87mm which is within the tolerance.

Fresh from my experience with the chainring bolts (which were stuck fast with thread lock) I must admit I was concerned about the amount of thread locking compound on the supplied cups.



I recall a stuck bottom bracket in my Bianchi many years ago, my local bike mechanic had a neat trick for removing it.  He removed the crank, closed the shop, then welded the spindle to the bottom bracket shell.  Once it had cooled, he refitted the crank and used that to unscrew the shell.  A few scorch marks later and I was upgraded into the world of cartridge bearings.  His summary of the situation: somebody was being mean with the grease.

The instructions that come with the crankset don't mention the need to apply a thread locking compound and in a close look at the installation video it appears that the threads are clean too.


One of the problems with information on the internet is that it tends to be strongly biased towards people with problems.  Bike riders with noiseless, trouble free bottom bracket installations are probably not logging on to complain or post to forums about the issues they're having.  Hopefully they are out riding and enjoying their bikes!  A search for the similar but high-end ultra-torque will throw up threads like this one from the RogueMechanic.  There are all sorts of interesting bits of information (and doubtless mis-information) in this post and its associated comments.  Anyway, for comparison here are the two videos of the Ultra-Torque installation:



Notice that the first 5 minutes of this video show the preparation of the shell, which emphasises the importance of this step.  It is interesting that they left this out of the Power-Torque video.  If you aren't content with doing something the correct way you can always follow the inferior (incorrect?) procedure instead, also documented in an official video!  This one uses copious quantities of Loctite 222, a liquid thread locking compound.



Given that thread-locking compound is basically glue, and that my experience has been skewed towards things getting stuck fast rather than shaking loose in this department, I scraped some of the thread lock out (it would be impossible to get it all out without a suitable solvent I think), applied some grease and tightened the cups up to the recommended torque.

Unlike the bike in the first video, which appears to have right-hand threads on both sides of the shell, my bottom bracket is BSA or 'English' threaded so you have to do up the drive side anti-clockwise.  There is a good article on Wikipedia about bottom brackets in general, including the various sizes.  When ordering the Power-Torque cups you do need to know which you have.  The reason that the drive side has a left-hand thread is to reduce the tendency of precession to undo the cups - the fact that it goes backwards may seem unintuitive but the linked article has a cute animation which demonstrates the effect so that you don't have to do the maths yourself.

If you are convinced that precession is your enemy here then the risk of loosening must be greatest on the drive-side of an italian threaded bottom bracket.  I expect I'll take the drive train apart for servicing at some point and I'll report back on the torque required to undo them - if I have a suitable torque wrench, which brings me to a bit of a gripe...

To help me get the torques right on this part of the project I bought a new torque wrench, on special offer, for a surprisingly cheap price.  I have a small wrench that goes up to 25Nm but this is not enough for the cups, the crank fixing bolt or the pedals.  The wrench I bought was a draper 1/2" drive ratchet type wrench.  I bought it from a fabulous local hardware shop called Mackays - this shop is famous in Cambridge for having the type of expert staff who can find replacements for pretty much any type of weird fixing you throw you at them.  Anyway, the wrench has a reversible ratchet and a scale marked from 30Nm up to a blood-vessel bursting 210Nm.

Armed with my new torque wrench I set about the cups, with the aid of the special purpose Campagnolo tool (I had expected this tool to fit more snuggly on the cups).  I started on the left (non-drive) side of the bike and tightened the cup without any problems.  I then flipped the ratchet and started tightening the drive side.  As I was just learning to use this tool I set the torque to the lowest setting each time (30Nm) to help get the feel of the thing before tightening to the recommended torque.  This was a good thing, because as I tightened the drive side I quickly realised that I was having to put in more effort than expected to get the wrench to break away.  It was only later I noticed the small print on the leaflet that came with the wrench: "IMPORTANT: The torque wrenches detailed in this instruction leaflet are for right hand torquing only.  They are not designed for left hand use."  I finished tightening the drive-side cup by flipping back and forth with the ratchet until I could no longer undo the cup using the specified torque.

So my gripe is why advertise these wrenches as having reversible ratchet heads?  Obvious you might say, it allows you to undo things, just like the guy in the Campagnolo video who clearly uses a similar torque wrench to undo the cups.  But this doesn't explain it, the warnings section of the leaflet kicks off straight away with "Never use the torque wrench to undo bolts, nuts or fasteners, as this will damage the ratchet and the calibrated setting".  I reckon that, at this price, they know that the tool will not be worth calibrating and that it will turn in to a fancy breaker bar after a year or two of use.



















Saturday 28 April 2012

Cranky delays to my home-build project


Most of the components I bought for my new bike have come preassembled ready to be fitted.  However, there was one component I had difficulty sourcing: the crankset.  How can buying a crankset be so hard?  After years of cycling on 170mm cranks I've decided to go shorter and ride on 165mm cranks.  This is partly because I tend to spin a bit but also because I find that my saddle adjustment height has very little room for error.  Last time I changed my frame I suffered a little knee pain on longer climbs (especially if I was sitting back).  Moving the saddle up solved the problem.  This is a fairly well known effect, I found this blog post on an Audaxing blog in which the author covers some fine adjustment issues for injury prevention (though take note of the comments at the bottom of the page as the knee conditions have been transposed in the main article).

There is plenty on the net written about crank length, much of it contradictory.  Performance cyclists are always looking to gain an advantage so it is not surprising that the subject has been studied but the surprising conclusion seems to be that the optimum range of lengths for a given rider is quite large.  Sheldon Brown comes to a similar conclusion with a more general purpose outlook after experimenting with a wide range of sizes.

Despite all this orthodoxy telling riders that one of three sizes fits all I've still decided to go with the 165 and ride for enough miles to see if I like it.  Clearly shortening the crank length by 5mm will mean moving the saddle up by the same amount to maintain the same leg extension at the bottom of the pedal stroke.  At the top of the stroke the foot will then be 10mm lower than before - a significant reduction in the height of the knee.  There are so many articles on crank length on the internet it is hard to pick out particular ones - and anyway, I'll surely just pick the ones that agree with my own analysis!  Still, this blog post makes the point above very clearly: Crank Length - which one?.  The shorter crank will also reduce toe-overlap as my foot will be retreating by 5mm from the front wheel.

Starting from this year, Campagnolo are making a Centaur crank in a 165mm size.  According to the brochure "it allows for an agile pedal stroke and a correct movement in relation to the length of the lower limbs".  By the way, at the time of writing nobody has told the webmaster at Campagnolo so the product page still lists 170mm as the smallest size and the link to the 165mm crank goes to the Athena 11speed crank but I can confirm that I do have a 2012 10-speed 165mm Centaur crankset.

Campagnolo Centaur Crank
Campagnolo Centaur 50/30 Compact Crankset: including warning stickers!
The crankset is only available on the more expensive carbon version unfortunately and I struggled to find anyone in the UK who had anything other than the compact 50/34 and even that was hard work (and like buses, you wait ages for one and then two turn up at once - isn't internet shopping fun).  Judging by the number of people that offered me the 'black/red' version (which is the same crank with red bolts) this looks like a bit of an unnecessary addition to the product range and inventory might have been better served by reducing the colour options and concentrating on the different lengths and chain ring configurations.

The thought of a 34T chain ring scares me a bit, even with the shorter crank that would be a lot of gears that I only ever used when taking holidays to places with long steep climbs.  To put this in perspective, the average force required on each peddle stroke with the 165mm crank is roughly equivalent to adding a single tooth to the chainring, so my 34T would feel a bit more like a 35T.  That would still be a big change from the 50/39 I currently use.

On the plus side, a larger difference between the two chainrings reduces the overlap in gear ratios.  For example, on a standard 12-25 set of 10-speed sprockets only 5 of the sprockets used with the 50T ring result in longer gears than the longest available on the 39T ring (ignoring the small-small combination).  With a 34T inner ring this increases to 7 sprockets.  On the minus side the bigger spread of gears inevitably means more frequent changes between chain rings or more temptation to cross-chain.

Campagnolo don't make different chain ring sizes for the lower-end Centaur but there are third party rings available that fit the Campy 10s cranks so a little experimentation seems possible.  As a result, I did go with the 50/34 compact but I also bought myself a 36T ring made by TA, as the graph below shows, this basically represents a single downshift on all the sprockets with a new hill-climbing gear that may come in handy next time I visit Holme Moss.

Typical bike speeds for different chainring and sprocket sizes.
Before anyone gets the idea that this blog is recommending you attempt to change your own chainrings, let me remind you that Campagnolo suggest that this can only be done by them (doubtless with approved parts) and that you risk ending up with rings that are out of true, followed shortly afterwards by accident, injury and even death.  The cost of the carbon-wrapped cranks is a bit eye-watering so I don't think one should undertake this job lightly.

TA Nerius 36T ring for Camagnolo compact crnnkset

The 5th Chainring Bolt Mystery

Firstly, the chainrings are fixed with 5 bolts, 4 on the rings/spider and a 5th bolt that goes directly into a thread in the crank arm itself.  The bolts all have a T30 torx screw head but on the reverse the 4 main bolts have solid nuts (which are actually the bolts as it turns out) with wide slots.


Also, to make life interesting the 5th bolt has what looks like a tamper-proof plug in it.  A pair of tweezers reveals that is actually just a removable plastic plug - my assumption is that it is to keep the dirt and water from going down the Torx head and into the crank arm where it might cause trouble (such as corroding the thread in the crank itself).


Seeing red

The bolts are alloy rather than steel and the crankset stipulates a torque of 8Nm, however, the ones supplied with my crankset were stuck fast with what looks like a white, dry thread locking compound.  Most of them came away without too much trouble but two of them were stuck so fast that I damaged the slot-heads trying to remove them.  Beware, the teeth on those outer rings bite!

Initially I tried to undo them by holding the crank arm using the gentle grip of my workmate (which has soft wooden jaws) just to hold it still.  This frees up both hands to work on the bolts.  However, with stuck bolts I needed this lifesaving tip from the 'boston bicycle mechanic' to help me free them up.  With the torx head held fast by the jaws of a vice I could use the slot-headed driver in one hand and my other hand was free to turn the whole crank in sympathy with the nut.  If I had read that article first I might have saved myself some time and money!

So, having compromised a bit on getting a compact, mainly because I couldn't find anyone who could supply a 165 without red bolts, I now faced the prospect of sourcing replacements anyway.

Spare Parts

Full marks to Campagnolo's website for the pretty PDFs with clear pictures labelling the various spare parts.  It was clear they came as a set though it was a bit disconcerting that the picture didn't match the bolts I'd just taken out.  Also, my bolts are clearly marked with the codes from the Record bolts of 2010 and earlier (the images above can be expanded to read the FC-RE303 printed on the 5th bolt).  There are various (cheaper) third-party bolts which look like they've been designed as replacements for the Record bolts but nobody has updated their catalogs to say, one way or the other, if their bolts will fit the 2011 Athena/Centaur/Veloce cranks.  For the avoidance of doubt, BBB's BCR-53C product "specially designed to be compatible with Campagnolo compact cranksets" do not fit, though BCR-54C looks tantalisingly like the right thing, despite being described only as "compatible with Campagnolo 11 speed chainrings".

Having already had to wait to do the build due to work commitments, travel plans and then illness I was in a hurry to get this problem sorted so ordered a new set of Campy original bolts from Belgium (from All4Bikes) and watched my profit margin from doing a home build go up in smoke.