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Thursday, May 28, 2009

Retul Bike fits

If you've read my blog before you know that I use the Retul system of motion capture ( I get a lot of questions about it -- and a lot of business frankly.

I often hear,

"Wow, that must really make the fittings easier, huh?"

After using the system for a while now I finally have an answer to that. Does it make the fittings easier? The short answer is "No", unequivocally, it does not make the process simpler.

Blasphemy, right? Retul is definitely the most influential technology to come into bike fitting in, well, maybe forever, and here I am dissing it?

Well, I don't think it is a "knock" on the system because it doesn't make bike fits easier. People and companies (i.e. Specialized) have been taking a reductionist approach to bike fitting and it has done nothing positive to the process. The *Fit Kit", *BG Fit*, *Wobblenaught* among others have tried to take this very complex process and turn it into a nice neat, packaged "revenue driver" that every bike shop in the world can become an expert in.

I think it is actually a tribute to the system that it doesn't "dumb down" the process. It in no way tells you what you should do to take corrective action for the cyclist - it just provides a lot of very accurate data about the cyclist's mechanics.

For each of the parameters it measures -- for instance the frontal angle a rider's knee tracks at relative to the vertical, called Knee Travel Tilt -- Retul provides a range of normal limits that each one, in an ideal situation, should stay within.

The difficulty lies in the shear amount of data. If you focus on one measurement and make changes to the rider's position to "fix" just that one measurement, often other measurements that are also a problem, don't change or get worse.

So, no, my bike fitting process has not gotten simpler. But I'm not the least bit disappointed. Actually this has been the most productive and fun year for me with bike fittings (in my 12 years as a physical therapist).

My bike fittings have gotten better, and that's the important part. The Retul system has allowed a level of accuracy and confidence that is hard to beat. Plus when it comes to bike fitting, "simple" isn't always the best solution.

But "better" is.

1 comment:

  1. I know you wrote this ages ago ... but ... I am stunned that nobody seems to have published the results of the same rider(s) on the same bike(s) after Retul vs after BG fits. I had a full BG fit in the USA 2y ago - made a stunning difference in terms of pain relief, stamina and speed. Came back and wanted to have a fitting on my other (better - not to be risked when flying to the USA!) bike and went with Retul (the fitter also did BG although because of lack of space they didn't do the full body measurements/assessment - which seems kind of crazy to me having had a proper BG fit). The two bikes are set up VERY differently - notably distance from saddle to bars (both bikes have the same saddle), fore-aft relationship of saddle to bottom bracket, and vertical distance of bars below saddle. Which do I prefer? I'm not sure (probably haven't been doing enough cycling to make a very considered assessment, for various reasons) ... but I am very curious that the two are so very different.