A previous Savvy Cyclist post describes bicycle gearing, and how to accelerate. This post gets to how your legs can produce power for a day’s ride without getting sore – and for a lifetime without wearing out.
Pistons, not pendulums
When you walk, your legs are like pendulums. Stand on one leg and swing the other forward and back. It has a natural, easy swing. Swinging it either faster or slower takes effort. Here’s a one-minute video illustrating the point:
But when you are riding your bicycle, your legs do not work as pendulums. Neither do they support your weight. They are pistons in an engine, connected to cranks. Because the cranks keep your legs turning, they can easily go faster. Let’s look at how this works out.
From one-speeds to bicycles with gears
I rode single speed coaster-brake bicycles as a kid. I got my first bicycle at age 7. Its small wheels had me spinning the pedals.
The next bike was big and heavy. I quit bicycling because I couldn’t ride it up the hill to my elementary school.
I first rode a bicycle with gears at age 17. It felt like flying. As is well known, the Wright brothers studied the flight of birds, helping them design their airplanes. But also, let’s remember that the Wright brothers were bicycle builders first. A bicycle, like an airplane, banks into turns. No earlier vehicle had done that.
Still, English three-speeds were geared too high to suit me. My career modifying gearing began with my installing a larger rear sprocket on my three-speed, so it would cruise along nicely in top gear and climb smartly in low gear. Really, a three- speed, so modified, is fine for urban riding if hills aren’t super steep.
From bicycles with gears to bicycles with more gears
After ten years riding on three-speeds, I got my first derailleur-equipped bicycle. I almost immediately modified it to get smaller steps between top gears and a lower bottom gear.
I’ll grant that gearing options have improved considerably over the years. Any mountain bike has a nice, wide gear range. Road bikes tend to have more gears but a narrow range: a racer mentality prevails, and these bicycles often need modification to work for ordinary people. Here’s the drivetrain of the road bike I use for recreational riding: It gets me up the hills!
Now, 7- and 8-speed internally-geared hubs are common. 11 and 14 speeds are available, too, though expensive.
What is the comfortable swing?
My legs are nearly as long as the grandfather clock’s pendulum in my video, but they swing twice as fast, because most of the weight isn’t at the bottom. It’s march tempo in music, no coincidence.: If you wear heavy hiking boots, your gait will slow down. But again, your legs are pistons, not pendulums when you ride a bicycle. The faster your legs turn, the less hard they have to push to produce the same power – so you can ride all day without getting sore, and for a lifetime without wearing out your knees.
A good pedaling cadence is quite a bit faster than a walking pace. With an optimal cadence, your oxygen-carrying capacity sets the limit of sustained power production. Your lungs don’t get sore by breathing hard, and your heart doesn’t get sore by beating faster. You can ride all day this way. .
Building muscle strength is something else entirely
Here’s another way to look at the issue: muscle-building exercise stresses muscles to their limit. The usual advice is for three sets of ten repetitions, to exhaustion, twice a week. More repetitions than that won’t build muscles any faster, they make you sore, and in the long run, can cause permanent damage. But, in an hour’s bicycle ride, your legs turn around thousands of times.
Certainly though, you can apply full muscle power for short bursts of power. Keep it in reserve for when you need it, because it fades quickly, and then you have to return to spinning.
Where to turn for more information about bicycle gearing
Getting the right gearing is simplest if it is original equipment on a bicycle you buy. But if your bicycle’s gears do not allow you to climb hills at a comfortable cadence, answers are as close as the nearest bike shop. Every kind of bicycle, even one-speeds, allows modifications.
For more details on modifying gearing with an internal-gear hub, you might look here:
and for derailleur gears, here:
In the next article in this series, John Brooking describes three approaches to riding in the real world.