Wednesday, July 28, 2010


So rule number one for racing is don’t make any changes right before the race, right? Everybody knows this. Don’t try new food, new equipment, new anything on race day. Especially don’t mess with your position on the bike.

With this in mind, I went in for a bike fitting last Friday, the day before the Chalk Creek race. I haven’t had a bike fitting in a few years. The last time I was fit was on the frame before the frame before the frame I am on now. I just sort of transferred the measurements I had and tweaked them a bit to make sure I was comfortable and the bike handled well.

I had been thinking I should probably have a fitting for a while when Eric from Bikefix offered to do one for free after the Miller Race a couple weeks ago. They’ve started using the Retul fit system and said they’d do a fitting if I’d help spread the word about it via my blog. Does this satisfy my obligation? No? OK, I’ll tell you how it went.

What constitutes a bike fitting really runs the gamut, depending on who’s doing the fitting. Some fitters, like the famed Max Testa, just sort of eyeball things. And if you’re experienced and know what to look for, this can work pretty well. Others use tape measures and protractors and do some number crunching. This approach works well provided the position they measure you in is the same as the position you’ll actually be in when you’re pedaling the bike.

The cool thing about Retul is that it’s a dynamic system that measures you under load. How this works is they stick a bunch of LED markers to your joints and have you pedal on a trainer. The sensors then measure the various angles and distances and compare them to a range of values that, based on their research, are most efficient.


imageIt’s three-dimensional, so it captures not only angles and distances, but also lateral movement in your pedal stroke. 

All the measurements of your bike are also taken, so you end up with a dataset that can be used when setting up additional bikes.



So what were the results? Turns out, my fit on the bike was pretty good. Everything was within their recommended ranges except I should have been a little further behind my pedals. Eric adjusted the saddle fore/aft and height a bit and then I got back on to see how it felt. I was comfortable throughout the 3+ hour race on Saturday. (And if I hadn’t been, Eric was in the break with me, so I could have made my feelings known on the spot.)

The one thing that would add to the utility of a Retul fit session would be power measurement. The Retul software has the capability, and for the fitting I was set up on a Cycle Ops trainer that’s compatible with a power module, so it’s an option if you’re willing to put in the extra time and effort. For someone that’s getting set up on a new TT bike, measuring power as changes are made in position would be an essential part of setting up the bike. In my case, where I was on a bike I was comfortable with already and the changes were relatively minor, I don’t know that measuring power before and after would have made any difference.

I remember when shopping for my first bike wondering why manufacturers even published geometry tables, because I couldn’t make sense of the numbers and didn’t know how anyone else could either. With experience I learned what the numbers meant, how to use them to select the correct frame size, and how various differences affected the bike’s handling characteristics. I’m also quite the bike nerd and suspect not everyone spends hours staring at geometry tables before buying a bike. But even with the right size frame and the right frame for your needs, getting it dialed in can increase comfort and efficiency and make riding generally more enjoyable. Bikefix has a great a system with Retul to help select the right size bike or make the bike you’re on fit that much better.

1 comment:

  1. Every bike geek spends hours looking at geometry. Only riding lots of different bikes can let one know what one prefers.

    You are a total geek to do that fit thing though. I am jealous.