Your crankset consists of number of different parts – cranks, bottom bracket (together called crankset) and chainrings.
Cranks: Two crank arms are mounted either side of the from at 180 degrees to each other, connected by an axle. The axle is threaded through the bottom bracket (BB) screwed into the frame’s BB shell, located at the meeting point of the seat tube and down tube. The pedals are attached to the other ends of the crank arms.
Crank arms can be made from a range of materials, including steel, aluminium and carbon fibre. Steel cranks are common on older bikes and BMXs, with aluminium found on most low- to mid-range road and MTB cranksets and the lightweight but expensive carbon fibre generally reserved for high-end cranksets intended for racing, on-road or off-road.
For road and MTB bikes, aluminium cranks are considered to be tough, stiff and light for the price. Most manufacturers will make some efforts to shed weight while maintaining stiffness, with some favouring hollow crank arms and others machining away excess metal.
A key consideration when upgrading or replacing crank arms or cranksets is crank length. Most cranks for road and MTB use are 175mm long, but riders with legs shorter or longer than the average may feel more comfortable on cranks that better match their measurements. Options from 165mm to 180mm cover different limb lengths – it could be worth your while to research what crank length is recommended for your inside leg measurement.
Read more
