Crank construction

[daggavis]

This is for you techies..

 

My question is regarding carbon cranksets..Are the crankarms entirely made from carbon or is it alu wrapped with carbon?

 

The arm that is attached to the chainrings with the spider (5 arms), is the spider also entirely made from carbon?

 

Trying to work out which (alu or carbon) is actually stronger..

 

Thx

 

[Kiwi]

Some are pure carbon, some have an alloy I-beam down the middle and some are carbon wrapped alloy. Same goes for the spider. Not everything made of carbon is lighter or stiffer.