crank length

 

Until a while ago, it was said to be 1/10 of the height, but most of them are 170, 172.5.
I think it was normal.
When the crank extends 2.5mm, it turns a circle with a diameter of 5mm up and down.
If you make it a circle, the circumference will increase by about 17 mm.

The short crank has little vertical movement, so even people with a low saddle can turn it comfortably at top dead center (the position where the crank is raised to the maximum).
Conversely, a long crank can rotate even a heavy gear somehow.

If anything, the short one is a rotation type, and the long one is a torque type.
It is influenced by the flexibility of the back of the body rather than the length of the legs.

A short crank is easy to rotate and can be turned compactly.
Touring and those who turn light gears may try it.

Long cranks can turn heavy gears to some extent.
Race-minded people will like this one.

If you shorten the crank, you will be surprised at how easy it turns, but if you turn around and go up a slope, it will be difficult.
You may not be able to step on it. It is normal to use longer ones for slopes that require torque.
Since the amount of exercise is the same whether it is short or long, I think it is ultimately related to the flexibility of the body.

If you're a pro, try to make it as long as possible.
The reason is that it can handle hills, and the long crank makes it easy to ride in tough situations.

Some pros raise the saddle by increasing the length of the crank.
Since the bottom dead center is far away, raise it little by little.
If you use it as it is, the back of the thigh will be pulled because the leg cannot be raised at the top dead center.
This pulling will interfere with the opposite stepping, so be careful.
Raising the saddle lengthens your legs, so start with a low rotation to get your legs used to it.

Conversely, it may be lowered (mostly lowered). In this case even for ordinary cyclists
It may be good, but it may become cramped because the top dead center of the crank becomes higher.
This is a difficult point when making a longer crank.

When the crank is shortened, it is fine as it is. The smaller the range of motion, the easier it is to turn.

After all, after trying various things, you will find the length that suits you.
In the case of the end, when I started cycling, it was 165, but after changing it to 170, the hill became easier.
I returned it to 165 once, but even if it was easy to turn, I couldn't get the speed because of the gentle slope and headwind.
Back to 170 again.
Slope TT may be 172.5

When I was a professional TT, I added a 175 that was 5mm longer if it didn't affect my body (within 40km).

Summary
Touring, constant running: short
Race, TT, hill climb, long
What a place, such as.