2
votes
1answer
1k views

Why does my non-drive side crank arm come loose?

I tighten the bolt super hard. Ride for a while. Then it comes loose again. I don't know if its my BB or the bolts. How can this be fixed??
21
votes
7answers
2k views

Are Z-shaped cranks a good idea?

I've stumbled across this kickstarter project, which promotes an original shape for cranks: They claim a wider arc of useful push during rotation. While their main point is rendered moot by ...
11
votes
4answers
5k views

Differences between Biopace and Rotor cranks

On mountain bikes of a certain age, "Biopace" chainrings are ubiquitous. These chainrings are (purposely) not circular. It seems that most people today agree that Biopace rings didn't live up to the ...
19
votes
2answers
407 views

Selecting the right crank length

What is the best way to determine the correct crank length for my height and more specifically my leg length?