Good bike fitters

Most bike fitters will use a method or a device for their bike fitting. The method has to do with the class they took to become a bike fitter, or the name of the person teaching that class. The device is usually a motion capture device of some sort – a measuring tool. None of these things imply that the fitter really understands how a bike should fit, or all of the things that go wrong when interfacing a human body with a machine.

Most bike fitters are crap. There, I said it.

I have done countless fittings on people who have had “professional bike fittings” done before, yet they were clearly outside of their range of motion in some way. It was a professional bike fit in that they charged money for their [dis]service, but that doesn’t imply they knew what they were doing. I blame this on how bike fitters become bike fitters. My first experience with bike fitting was with a system called FitKit – probably the first bike fitting system. I was shown how to do fittings by Peter Mooney. He showed me how to take all the body measurements, and how to use the charts to see recommended saddle height, top tube length and stem length. Then he said something I will always remember, he said “then take a step back and put them on the bike right”. So much for fitting systems.

There are two problems I see in bike fitting: First, bike fitting classes are at most a week long, all of the ones I took were 4 days or less. There’s an old saying about how much time it takes to master a craft – you get my point… The second problem is quality control of the human body – it sucks!!! If the worst bike fitters fit the same person over and over again they would eventually get it right. They don’t, each person is different in more ways than you can imagine. Fitting becomes problem solving which none of the fit schools teach.

My education in bike fitting was different than most. I started coaching the Harvard cycling team. That job involves fitting riders, solving problems, observing how they ride, making more changes… It was an education like no other in bike fitting. It didn’t allow me to assume that anything worked (because most things don’t). It is what I feel is a much needed step in the process of becoming a bike fitter. Over the years there have been about two dozen other fitters at my shop, none of them made a point of riding with their clients to see what really happens on the bike. The other fitters at the shop now believe that lowering the handlebars will reduce the amount of weight supported at the bars – it seems to work on the trainer. How can anyone do this job for years and not understand the effects of gravity???

The ideal fitting

Most fitters doing a “full professional fitting” will schedule 3 hours or more. It starts with an interview, goes on to a physical assessment, they work on the shoes and cleat position and then the rider gets on the bike and they start looking at their position and how they pedal. Somewhere along the line there will be coffee… Many of these fittings use video or motion capture using markers on key landmarks on the body. What the rider winds up with is a new position on the bike and documentation of both their bike set-up and what has been changed. They leave a few hundred dollars lighter, feeling like they now have a perfect position on the bike.

At some point they get on the bike and start riding, and things begin to change. The fitting was done on a static bike which was held solidly in place, a bike rolling down the road is different. More than half of the problems that people have on a bike are caused by dynamic conditions. The hyper accurate measurements taken by the motion capture camera are no longer valid. Your body will adapt to the changes of contact points. This may be good or it may be outside of your range of motion…

My point is that long, in-depth, expensive fittings aren’t putting you in the perfect position. It’s what I call accurately measuring Jell-O, it’s kinda pointless. You would be better off spending far less time on the first fitting, do some riding and then come back to fine tune it. You could also double the amount of coffee you drink this way.

When I first started fitting riders I made the mistake of riding with my very first fitting client. What I learned was the basis for what’s above. This gets back to my theory of testing vs. willful ignorance. Motion capture makes this so easy to test. Do a fitting on a rider using Retul motion capture, have them ride for two weeks, do another fitting, compare the numbers. Nobody that I know of has ever done this.

The best fitting work I do is for my coaching clients or people I ride with. I have never done a fitting and then gone riding with that person and not found something I wanted to change while watching them ride. I do good work for the clients I only see in the fitting studio, but I see no reason to have a 3 hour dog and pony show. There’s plenty of real fitting work to be done.