Inspiring Sports Technology
Tour tech: Wheels
Thursday, August 12th, 2010
This has been one of the most varied first weeks of any Tour de France for many a year and as a result the bike tech junkees have been saturated with all sorts of equipment flashing across their screens. In the space of 5 days has seen the world’s best cyclists tackle a flat prologue, the rolling hills of the Ardennes, the cobbled roads of northern France and Belgium, with a few rough and tumble sprint stages thrown in for good measure.
Whilst we have all undoubtedly enjoyed a break from the monotony of a first week packed full of bunch sprints punctuated by the odd break-away success, the team mechanics will have been working over-time to make sure the riders bikes have been kitted out with the best gear to tackle the unique challenges each stage has presented (some mechanics, like Saxo Bank will even have been working time and a half to put their bikes back together after the crash strewn stages 2 and 3!).
More often than not the fundamental consideration during a time trial is aerodynamics and Saturday’s prologue was no different. With the majority of riders choosing a rear disc wheel the only difference between riders selection was the depth of their front wheel rim. Typically the GC contenders and time trial specialists were aiming to shave as many seconds as possible by taking the deepest section possible (around 60mm) whereas the sprinters adopted a slightly less aero, but more stable front wheel, with around about 30-40mm depth. The benefit of such wheels is that the air flows over them much easier, thus requiring less power from the rider. The flip side of this, however is that the wind moves through them with less ease, meaning you will very rarely see a disc wheel or overly deep rims being used on time trial or road stages where cross winds are a factor.
The first stage was the first chance for the sprinters to stretch their legs and, as a result, the majority of the peloton had their deep section road wheels on. Most were riding on rims around 50mm deep as the finish was set to be a fast one and they would have been looking to gain as much aerodynamic performance as possible without compromising handling. Although watching the final corner might have had you thinking that Cavandish still had his time trialling wheels on! As well as cutting through the air easier in those crucial closing kilometres, deep section wheels also provide greater stiffness, a crucial factor when the big men start throwing their bike around the finishing straight.
Stage 2 posed a significantly more challenging proposition to the sprinters teams as they headed for the Ardennes and the first climbs of this year’s Tour. These were no ordinary climbs either, as the riders faced the prospect of three third category climbs in the last 50kms. This was the first time the riders would have to take into consideration their battle with gravity and as a result weight saving was very much the order of the day. The majority of riders abandoned their deep sections for lighter, shallower profile wheels, which would also offer them more of an advantage on the tight twisting roads which surround the fabled climbs which feature so prominently in the legendary Leige-Bastogne-Leige spring classic.
The day which demanded the most thought in terms of wheel selection was undoubtedly Stage 3 which took the peloton over the infamous cobbles of Paris-Roubaix. For this stage a lot of teams neglected Carbon rims, instead opting for more sturdy alloy rims. Whilst some riders, such as Lance Armstrong, kept faith with carbon rims, almost all of them deviated to a shallower 24-36mm rim. One thing the riders did have in common though was tyre choice. When it comes to racing over the cobbles the most important thing is avoiding crashes and punctures and whilst you can’t do much about the former, adopting a set of wider (24-27mm), tubular tyres will give you a much better chance of avoiding the latter.
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Thursday, August 12th, 2010
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