On the face of it, it’s a reasonable question, and one that I am asked on a fairly frequent basis: “what bikefitting system do you use?”. It is, however, something that you ask at your own peril, if you want a brief response at least, because the answer is rather more complex than the question might lead you to suppose.
A number of companies have done a pretty good job of marketing their own differing bikefit protocols, not only to the general cycling public but also to those in the retail bike trade, promising that their solution is the one that will set you on the road to a life of pain-free pedalling (if you’re a consumer) or provide you with a sure-fire, internet-proof revenue stream (if you’re a retailer). And that’s kind of understandable, because in order to sell something one cardinal rule is to be absolutely clear about what you’re selling; once your message becomes muddled then selling becomes a whole load more difficult, and let’s make no mistake, nobody invented a bikefitting system out of the goodness of their heart, oh no. Bikefit, or more accurately bikefitting technology and its associated licenses, up-sells and spin-offs, is a retailed product like any other and the sums therefore have to add up, whether you’re in the fitting room or the R&D lab.
Therefore the promise, whether you’re the final end customer or an intermediary like me, has to be: “our system will sort you out”. Period. Okay, so that’s fine, except it’s not necessarily true. Over a period of years I have been “officially” trained in four different bikefitting protocols, and have concluded that no single one of them can guarantee a one hundred per cent result, on one hundred per cent of riders, one hundred per cent of the time. This is because, essentially, fitting systems rely on an aggregation of data from a sample of riders, and while for the big players such as Specialized and Trek this is a pretty large sample it still boils down to creating a set of parameters into which riders are expected to fall. Not as crude as a simple average (although some of the more rudimentary systems do, indeed, reduce things to this) but nethertheless an envelope of physical characteristics outside of which some riders will inevitably fall.
Now, don’t get me wrong here; I’m not saying that any single protocol I’ve experienced is complete rubbish (well there is one, and it’s not among the four I’m going to discuss) because with experience all will deliver a pretty good result – frequently an excellent one – in the vast majority of cases, but there are times when the ability to blend elements from a number of different philosophies can take pretty good and turn it into excellent.
I guess that if you’ve made it this far you’re probably wondering which fitting systems I’m trained in, and what their strengths and weaknesses are, so here’s a very brief summary. I’m not going to get bogged down with a lot of detail about the different methods, and bear in mind that there’s been plenty of water under the bridge since I carried out some of this training and the content of the various syllabuses may have changed or moved on, but these are the systems as I experienced them.
First up was Trek Precision Fit, which is essentially a simplification of what is practised by Cyclefit (who carry out the training for Trek), and these are the guys who are pretty much responsible for introducing the concept of bike fitting to the UK in the first place. The system actually shares a lot with Specialized Body Geometry in that both use a set of defined, measurable angles, or angle ranges, for factors such as knee angle at point of maximum leg extension, back angle, etc and the juxtaposition of knee and pedal with the cranks in a horizontal position is what governs the rider’s position fore and aft on the bike.
I like the fact that Precision Fit works within angle ranges with the exact angle for, say, the knee at maximum leg extension, being down to the judgement of the fitter based on rider-specific considerations such as hamstring and spinal flexibility, whereas Body Geometry targets a single figure for this. The irony here is that the off-bike physical assessments carried out as part of a Body Geometry fit are super-thorough and one of the great strengths of the method, so obviously the way forward here is to use the two methods to inform the decisions made during a fit.
A third system, Retul, needs to be thrown into the mix here, and while it shares a measurement-driven approach it adds dynamic motion-capture, meaning that values and angles can be measured on-the-fly as the rider pedals, which in turn means greater accuracy. The sheer volume of information provided during a fit can be mind-numbing to an inexperienced user, and it’s a strength that can easily turn into a drawback if the fitter becomes so engrossed in the data that he or she forgets to ask the rider simple questions such as “how does it feel“. Another shortcoming used to be that the off-bike physical assessments were a little limited, but with the current merging of Body Geometry and Retul into a single system – Specialized have actually owned Retul since 2012 but chose to maintain its separate identity up until now – this has been addressed and the resulting system is a pretty powerful and comprehensive one.
Which leaves philosophy number four, Tony Corke’s Body Positioning System, and while I learnt this a few years back I’ve kept it until last because it differs fundamentally from the other three methods I’ve talked about. How? Well, in short because it doesn’t use a single angle, measurement or number other than to record the physical dimensions of the rider’s bike at the end of the session. It’s an intuitive approach, where decisions are all made based on rider feedback and observation, and while this may sound a bit like saying “oh, that’s about right” there’s more to it than that, because the communication between fitter and rider is carefully structured by the former in such a way as to provide he or she with accurate guidance as to how the latter’s position needs to be altered. It teaches a much greater understanding of how the rider’s weight distribution, balance and muscle activation is governed by positional changes than any of the systems previously discussed – which actually don’t pay that much attention to weight distribution at all – but can fall down when feedback from the rider is unclear or contradictory. Fortunately, if that should happen a knowledge of more conventional bike fitting methods can provide a safety net, but clearly only if you have that knowledge.
I accept that my descriptions of Precision Fit, Body Geometry/Retul, and Body Positioning are very broad brush, and each system has its evangelists who will no doubt be muttering about how I didn’t mention this, that, or the other, but the larger point I am making is that all systems have differing strengths, and using a balance of different protocols will give a superior result to slavishly sticking with a single approach. You might say that my “system” varies slightly with every fit I do but that’s because hey, front page news, the rider varies with every fit I do.