There is one question that crosses everybody’s mind when they first learn of fixed-gear bikes. Until you ride one yourself, it’s a foreign and mysterious experience that can be rather difficult to imagine.
Most bicycles have a freewheel attached to the rear hub that allows the rider to stop pedalling and let their momentum carry them forward. It’s what generates that repeating clicky sound. If there is no freewheel, no coasting mechanism, then what exactly happens when you stop pushing the pedals? What does it look like? And how does it feel to ride?
Perhaps you fear that you won’t be able to stop pedalling! Or that if you do, your legs will be swung wildly this way and that. Or maybe it triggers a jarring jolt that jumps up your spine like an unexpected encounter with a pothole.
Truth is: riding fixed-gear feels really damn smooth. Among the many reasons to ride fixed, ride quality may be number one.
Enough rambling. What actually happens when you relax your little legs? Like I said, the best way to find out is to hop onto a fixed-gear bike yourself. But if you don’t have one handy, the following might give you an idea:
When you stop pedalling on a fixed-gear bike, your legs are relaxed but the pedals continue to turn anyway. The pedals will gently but firmly push and, with foot retention, pull your feet around to follow them. You can resist their motion, but this will only slow the bike down.
More specifically, as the pedal rises on the up-stroke, it pushes upwards against the bottom of your shoe, lifting your leg up. If you have foot retention (i.e. toe clips and straps or clipless pedals and cleats), then the opposite effect happens as the pedal falls during the down-stroke, pulling your leg downwards.
While all this pulling and pushing might sound uncomfortable or even quite violent, I promise it’s not that bad. Remember, the pedals can’t move your legs anywhere they wouldn’t normally go while pedalling—it’s as though you’re still pedalling but with no physical effort. It does take some getting used to at first, but once you become familiar with the forces and feelings involved, it’s actually really nice to ride this way.
Why don’t the pedals stop rotating?
Weird, I know. So why is it like this? What is it about a fixed-gear drivetrain that causes this mechanical behaviour? There are two important concepts about fixed-gear bikes to keep in mind:
- The motion of the whole drivetrain—from the pedals, cranks and chain ring through the chain to the sprocket and rear hub—is directly linked with and solely dependent on the rotation of the rear wheel; as long as the rear wheel rotates then so too must the pedals and vice versa; they cannot move independently unless the bike has a freewheel installed, has a loose chain or is otherwise malconfigured.
- When the bike and rider are in motion, they have a significant amount of kinetic energy or momentum that keeps them moving. As long as the rear wheel is on the ground, it must roll.
Combining the two facts above, we see that as long as the bike and rider are in motion, and the rear wheel is in contact with the ground, then the pedals must rotate correspondingly. If the pedals were to stop rotating, then the rear wheel would stop rotating too and the bike would come to a halt.
All this means that as long as you’re rolling forwards, the pedals must rotate. If you try to stop them they will fight back with considerable force! That force is powered by the kinetic energy you have stored up due to your momentum. The feeling of continuous, uninterrupted motion is what provides the really smooth and seamless ride quality that you just don’t get with a freewheel.
In fact, the kinetic energy stored is so great that, even rolling along at walking pace, you can stand on one leg on a pedal and the bike will lift your entire bodyweight up and down a few times as it slows down.
Is there any reason to resist the motion of the pedals?
In some situations, yes. As a matter of fact, this is exactly how you slow down without using a hand brake. Resisting the pedals is also necessary for a number of other deceleration techniques including skip-stopping and skidding—but that’s a topic for another article.
Additionally, pushing the pedals gently in the opposite direction is a crucial part of the track stand and other tricks that can’t be done quite so easily, if at all, with a freewheel. You can even pedal along in the opposite direction to ride backwards.
Learning these skills takes some practice but they are immense fun once mastered. Also, resisting pedal motion will exercise different muscle groups, helping to build strong legs.