Wednesday, 7 May 2014

Campagnolo 12-30 Cassette Review

I live in a flat part of the country but I'm a frequent visitor to the Buttermere area of the Lake District. As a result, I often find myself climbing Honister Pass from the Buttermere side. To me, Honister is one of the hardest climbs in the area. The climb finishes with a stretch of 1 in 4 (25%) and it really pays to save your legs and ignore the temptation to get out of the saddle too soon. You can get a rider's eye view from the picture on the visit cumbria website. If you prefer, you can watch ITV news coverage of the 2013 Tour of Britain climbing it too.


Why buy the 12-30 Cassette?


Last time I went up Honister I was riding my lowest 36x25 gear on my Cinelli/Centaur home build with 165mm cranks. That's as low as I want to go when riding around the area where I live and I thought it would be good enough to get up Honister but as I rounded the penultimate bend I didn't have the strength left to turn the bike into the wind and I was driven in to the left hand wall by a super strong gust funnelling through the gap. I grabbed the wall to steady myself and clasped the front brake but on that gradient the front wheel was never going to hold, I started sliding backwards and had to put my foot down. Defeated I vowed to come back with a lower gear.


Realistically it is difficult to make significant changes to the gearing on a bike routinely, you are likely to need to change the length of the chain and perhaps even the derailleur and if you are switching between a double and a triple you've got a major job on your hands. I decided to rejuvenate my old Tifosi alloy frame instead, I looked at the costs of getting a Veloce triple but decided I could almost get the same lowest gear with a Centaur compact double (50/34) and the new 10-speed 12-30 Cassette. I bought the whole groupset from Ribble - they've got a handy groupset builder which flagged the need for a medium cage derailleur rather than a short cage.


Installation


Installation was pretty simple. There are no special considerations as far as the wheel or hub is concerned. My Tifosi frame has a very short chain stay and that is the only thing that proved a challenge. Firstly, the Campy 'longest chain that can possible work' method of chain sizing left me choosing between a chain that was too short (by their method) or one that slightly too long. The tension was very low in the small-small combination and the chain was only just hanging below the cage. Still, better a little too long than too short.


With such a big cog you are going to need to adjust the 'H' screw to increase the gap between the sprockets and the guide pulley of the derailleur by unscrewing it (in my case, pretty much to the limit). This is the most confusing thing to me because the Campy instructions label the adjustment screws in a different way to most internet articles:


B screw
Lower limit
G screw
Upper limit
H screw
Cage spring tension

These instructions also don't specifically say which way to turn the 'H' screw to achieve the desired effect and, unlike the limit screws, you can't easily see the change. There is a better explanation on the the Park Tools site, but bear in mind that they use the letters 'L', 'H' and 'B' where Campagnolo use 'B', 'G' and 'H' respectively! Scroll down to the Campy specific para and you'll see a clear explanation of the rack-and-pinion style adjustment of the cage:


In this system, the upper spring is fixed. Increasing cage tension (turning screw clockwise) will bring the upper pulley closer to the cog. Decreasing cage tension (turning screw counter-clockwise) will increase the distance between upper pulley and cog.

Thank you Park Tools!


Road-test


As you might expect from a brand new groupset the shift is precise and the chain runs in that silky smooth way that I've now got used to with the Centaur equipment. The chain hops up to the 30T sprocket without any fuss or extra noise.


I set my bike up with a standard 50/34 compact crankset. The 34T chainring is smaller than my regular 36T but even if you are already riding a 34T compact you'll have two extra gears below what you get on a standard 12-25 cassette. It is worth noting that the first seven sprockets in the 12-27 and 12-30 cassettes are the same, it's only the last three hill-climbing gears that are different, changing from a 23-25-27 to a 24-27-30 combination. This means that when you are running on the big ring you won't really notice any difference between the two options. If you are changing from a 12-25 cassette you're swapping the 16T sprocket (which sits at #5) for a lot of extra leverage.


The day after finishing the build I took the bike for a test drive up Honister. I'm happy to report that, with the benefit of the 34x30 gear, I got up comfortably despite the brisk head wind and being a bit older and a bit less fit than I was last time. I stopped briefly at the top to take this picture for posterity.


Summary


With the top riders now choosing to climb in lower gear ratios for more efficiency it is no longer considered clever to thrash up these steep climbs in a big gear. Also, with 10 sprockets you can surely afford to keep a few back for use on high-days and holidays. In conclusion, one of my better purchases, I can now dream of tackling Hardknott and Wrynose.



Sunday, 20 April 2014

Bottom Bracket Shell Facing with the Cyclus Tool (video)

It's been a while since I posted something to this blog but I've started a new bike build. I'm restoring my old Tifosi CK Columbus frame. One of the great things about Tifosi bikes is the quality paint jobs they gave their frames. The downside to that is that the bottom bracket shell will need facing before I can fit a modern Campy bottom bracket.


Cyclus make an (almost) affordable tool that makes this job possible for the amateur. Unlike a lot of the more expensive options that combine shell facing and thread cutting the Cyclus Bottom Bracket Shell Facing Tool is just for facing.




I couldn't find an online video and the instructions were lacking in pictures so I decided to make a video of the process. See what you think.

Sunday, 6 April 2014

Bicycle Ambulance in Cambridge, my new LBS

Even for budding do-it-yourself enthusiasts the Local Bike Shop (LBS) plays an important role. When I bought my Cinelli Saetta (see previous blog posts for details of the build) it was reassuring to source the frame and fork through a local dealer and get someone more experienced than me to cut down the fork and fit the headset. That said, for my last build (a clunky winter fixie) I just ordered the bits over the internet, cut the fork and installed the cups myself. Perhaps it was just an excuse to buy a new tool. Anyway, there's one job I have never tackled and frankly probably don't have the time to learn, let alone to get good enough at: wheel building.


The Wheels


Alongside the Cinelli frame, I ordered some Miche primato hubs and some Mavic OpenPro rims and the team at my local bike shop, Howes of Cambridge, built them up for me. This is the second pair of wheels they've built for me. I bought a pair of OpenPro/Ultegra wheels form them in about 2007 and they have never put a spoke wrong. Although I stopped using the rear wheel when I made up the Cinelli the front is still in service on the winter bike.


The new wheels have done almost 2 years now and about 5,000 miles of fair-weather use. Perhaps it is the poor condition of the roads, or perhaps the newer OpenPro rims are not quite as strong as the older ones. Most likely the lightweight fancy black-anodised spokes with alloy nipples just make for a slightly weaker wheel. Whatever the reason, about a month or so ago my Cinelli bike acquired an occasional creak when climbing and I couldn't figure out why until last weekend when it suddenly sounded like someone had attached a badly fitting mud-guard (fender) to it. Something was loose and the culprit was easy to identify: a spoke had come almost completely free.


So Farewell then, Howes of Cambridge


Unfortunately, Michael and Pat Howes packed up business at the end of 2013. The shop had a long history with the local press identifying it as the oldest bike shop in the country. They got a write-up on road.cc too. I wish Michael and Pat all the best for their retirement!


My New Local Bike Shop


With Howes gone, I need to find a new bike shop. Of course, in Cambridge I should be spoiled for choice. I'm sure there are lots of great bike mechanics but it is nice to have a recommendation to go on and so I thought I'd give the Bicycle Ambulance a whirl based on a recommendation from my son. For £20 they fixed up both of my wheels and today I rode about 75 miles on them and they are as good as new! With all creaks solved the soundtrack of my Cinelli Saetta is, once again, just the gentle purr of the Campag Centaur equipment.


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.