Jumat, 05 Agustus 2011
The thing is, I'm planning to buy a triathlon (aero) bike not only because I think it will make me go faster - which is always nice - but because I'm hoping to avoid the severe back ache I had for two weeks after doing the Ironman. Bike fitting is about finding the best compromise between aerodynamics, application of power and comfort. With my current bike this compromise is somewhat restrictive. The first part of the bike fitting involved being "fitted" on my current bike so that, not only could I get the best out of it, but the idea was to get recommendations of triathlon bikes that would suit me best and - most importantly - be advised on what size frame to go for. The last thing I want to end up doing is shedding a whole load of cash on yet another bike only to find that I am just as uncomfortable (and just as slow). All the different triathlon frames have different characteristics and vary how forward you are with respect to the cranks (seatpost angle) as well as the length (reach) and height (stack). So if you have relatively short legs with respect to your torso you'll want a bike with a longer reach for example.
First of all I got on my current bike (mounted on a turbo trainer to measure my power output) and some measurements were taken with a kind of protractor in order to determine my optimum seat height. Since I would be buying a triathlon bike it seemed to make sense to set up the road bike for a road position: this resulted in lowering the seatpost by about 3 millimeters (at a cost of about €50 per millimeter being the only adjustment that was made). To be honest I think that I am perfectly capable of sensing where the optimum seat height is but hey, it's nice to have it confirmed by an expert. If I decide to ride with the aerobars on this bike I'll have to raise the seatpost by those 3 millimeters again. There was a screen in front of me spitting out wattage numbers that no-one seemed to give any importance to but it certainly looked impressive and technical.
Well who cares about the old bike anyway? What I was really interested in was choosing the most suitable triathlon bike for my body shape. I expected the fitters to have tables of measurements from all the major manufacturers, all converted into some consistent format. Instead it was a case of me suggesting a brand that I thought was "cool" and the fitter looking on the website at the quoted dimensions and saying that it was too long, too short, too aggressive, too relaxed. What really annoyed me was that, in many cases, I knew more about the bikes in question than the supposed expert. In any case, he was basing my ideal measurements on my road bike with no clever adjustments to account for passing from a road position to an aero position or anything like that. I couldn't shake off the idea that I was being goaded in to buying a custom bike. These bikes (made by Guru) are carbon fiber bikes that are made to measure and are as expensive as that sounds. Don't get me wrong, they look amazing but if there is an off-the-shelf bike out there that fits me, then my money would go much further on the groupset and the wheels, for example. The point is, how can I be sure that the measurements were taken well enough for even a custom bike to be a good fit? I mean, they took a photo with their iPhone of me standing next to a screwdriver (for scale) so that they could supposedly get any measurements they needed, so I wasn't exactly filled with confidence. Bizarrely, the fitter also offered me a second hand Giant Trinity Advanced SL0 that belongs to Virginia Berasategui, a Basque professional triathlete, in size "S" for small! (I'm 6"2).
Anyway, the reason I post this now is because I came across a very interesting article in Triathlon Plus, written by Chris Boardman (British Olympic Gold Medalist in cycling). If bike fitting seems to me a bit like the black art of voodoo then it was refreshing to see someone - and not just anyone, mind - demystifying the whole bike fitting process. There are some very practical suggestions for how you can improve the fit yourself. Here's a link to the article.