Sunday, June 5, 2011

More Bike Weeny Stuff

I'm a fossil and come from the pre-cycle computer age. What's more, I like to understand machines so as to better work with them, but that desire doesn't extend to computers; I like to know as little of them as possible. Today's subject; bicycle gearing and attaching files to in Blogger.

For example, modern bikes have many gear options, the purpose of which are to decouple pedaling cadence from incline and wind resistance. In English, you can keep your feet moving at their best speed while the head winds and hills conspire to make you peddle too slowly.

Many have studied the whole business of cadence (peddle RPM) and how it relates to efficiency. Eventually all cyclists realize that when peddling easily a slower cadence is most efficient (70-80 RPM), when moving more briskly faster feet are more efficient (85-95 RPM), and when really delivering a best effort over a few miles, even more is is better (95-105 RPM). Why? Because slow twitch muscle fibers like low forces but are aerobically more efficient. Fast twitch fibers fire when forces rise. Curiously, the fast/slow naming convention is primarily a misnomer carried over from sport where higher speed and higher force go hand in hand. It's about high force/low force. It also explains why high reps just don't make you stronger.
While you can do this by feel, some calculations clarify, for me, what is going on:

Gearing, cadence, and speed calculations

If you click the down load tab to the right, you get a copy of an Excel file you can play with to your hearts content. Can't imagine why you would want to, but I needed practice.

Is this the best way? I seriously doubt it, but it only took a few minutes to figure out and it's a free service. Not bad.

1 comment:

  1. Hey! What kind of pedaling commentary are you trying to peddle to me?