Sunday, February 6, 2011

Changing Gears

I've been thinking about pedaling cadence - the number of times per minute that the pedals turn when riding. We are all supposed to have a "best" cadence, an rpm range that we can work all day. You might speed it up a bit with training but at some point you find your groove and that's your groove, so you live with it and groove with it. 

The common wisdom seems to say that a faster cadence - spinning- is better for long rides because it uses those legendary long lasting slow twitch fibers, whereas slowly pushing big gears - grinding- makes your fast twitch muscles burn through carbohydrates like a kid eating candy on Halloween - with a similar post binge crash. Crashing sucks, so you want to use the higher end of your range.

That's where gears come in. The ideal gear range should help you keep your groove by changing the pedal resistance (gear) so you can spin in your  best range. For more on this, probably the best Internet source is the invaluable work of Sheldon Brown, a man who shared his abundant knowledge of bike wrenchin'  and theory with the masses.

Fine-tuning a bicycle takes time in the saddle. Over hours of riding, whatever needs adjustment, correction or removal eventually works it way to the front and center of my attention, and I live with it only so long as I must. The gear set up on my bike has done its job well. But despite the last year of randonneuring, I'm not sure the job was done as well as it could be. The range was close, but could it be better?

 What am I preparing for? What am I capable of? Answering these big questions with simple honest points should make the the answers easier to find. 

So what am I preparing for? 

Beating the stripe.  Randonneuring is not a race, but there is a time limit to each ride. As Randonneur Keith Snyder described it in his post called Old Saybrook:

  If you imagine that the starting line is an actual stripe across the road, and you imagine it moving forward through the course at 9.3 miles per hour, that's the line you have to beat to each controle. You can stop all you want, eat, take pictures, sleep, fix a flat, weld a frame, have an affair—but the stripe keeps moving.

So, at minimum, I have to beat the stripe. Sprinting will not help do this. Maintaining an average speed that is faster than the stripe is the only thing that will.

A higher average speed.

The higher your average speed in an event, the more time you have for non-riding activities, like bathrooms,  food stops and, on long brevets, sleep.  So a higher average speed is good. What I have been most surprised to learn is the average speeds don't have to be that high to get all these benefits. A difference of a mile or two per hour over the course of a 200K makes hours of difference at the end of the day. Fast riders might average 15 or 16 mph over a 200k. If you average 14 mph, a 400K (250 miles) takes less than 18 hours which is 9 hours less than the 27 you are permitted. So its not about blazing speed.

Enjoying the ride - The views, the trip, the people, the experience. The ride is not just about the bike.

What am I capable of?

I believe than I can average, over the course of a brevet, 12-14 mph. I know that I can ride much faster than that for less than the distance of a brevet. But I can't do both on a brevet, I've tried that  - repeatedly - it doesn't work and it hurts. And don't forget the sixth commandment of cycling.

Gearing up for the season

So that is where the gear change comes in. Using Sheldon Brown's Gear Calculator (link). I figured out that my original gear configuration at my natural cadence would resulted in several speeds that were far faster than I needed for a brevet, and many that were too slow. In fact, at my natural cadence of 80 rpm, the 48/11 combo (my big chainring and smallest cassette cog) would have me going at 28 mph. Yeah right. Unless I am going down a steep hill, I will not be pedaling that bike that fast. On a flat course, I MIGHT be able to do that in a dead sprint. So, in reality the 11 cog was of no practical use. In fact, most of my gears were outside of my goal range at my natural cadence. In theory, that means that I spent most brevets either pedaling outside of my natural cadence, pushing too big of a gear or going to slow for my goal times.

Matching gears to my cadence.

I think what I need are more gears that put me in brevet speed ranges at my natural cadence, and a couple or three gears to get my big self up the big hills. Today, I installed a new cassette where the highest gear is a 13 and that adds more mid-range gears that, at my natural cadence, put me in a range of 11- 18 mph. That means my top speed at natural cadence is now a more practical, and likely to be used,  24 mph. But more importantly, it means I have more gear selections to fine tune my cadence in a range that suits my goals.

Now - if only the ice on the roads would melt so I can test this out.


  1. Nigel,

    Interesting, I tend to "float" at about 90 rpm. With a "fit" float closer to 100.
    Now, the longest I do this is for a century, so I'm not sure I would keep at it for the longer rides.
    Do you do any trainer work?


  2. This winter I've used a spin bike for indoor training. I think it has quickened my cadence to the low-mid 80's and it may still be increasing - we'll see. Having a controlled environment to work on it has helped. But I don't realistically see myself ever riding at a steady 90+ rpm for long rides.