Choosing the Right Crank Arms

Length, durability, strength - choosing the right crank arms is no easy task! Below are some of our recommendations and tips on how to make this process easier, plus details on what our Middleburn collection has to offer.

Determining crank arm length

A key consideration when upgrading or replacing crank arms or crank sets 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. In addition, a higher end crank will be stiffer and lighter, equaling greater pedaling efficiency and better front shifting to improve acceleration!

Changing your crank arm length can affect everything from your bike fit to gearing, so how do you know what’s best for you?

Body size is a good starting point

Proper crank length generally follows rider height. Fitters typically look at physical dimensions like femur length and foot size, both of which are primary lever arms in a pedal stroke. However, other factors like pedalling style have to be considered as well.

Discomfort or dull pain

Back and knee pain are often signs of improper bike fit and can be the most obvious indication for a need to change crank length, often indicating a too-long crank arm currently - changing your crank arm length will successfully change pedalling trajectory.


Many triathletes simply decide to invest in shorter crankarms in order to open up the hip angle at the top of the pedal stroke as the seat rises, which allows them to produce more power and acceleration from a more aerodynamic position.

Remember - If you do end up changing crank arm lengths, it will impact your gearing as well . Although the relative jumps between gears stay the same, the overall range will feel slightly easier or smaller with shorter cranks and harder with longer ones.

What cranks are available from Middleburn?

- RO1 Square Taper including tandem options

- R02 X-Type Crank for 68mm BB and tandem options

- RS7 Square Taper plus tandem options

- RS8 X-Type Cranks for 68/73mm, 83mm, 100mm & 108mm Bottom Brackets

Lightweight, strong and manufactured in the UK, Middleburn cranks can take the punishment of jumps, drops and stunts, all the while providing gravity riders with balance of strength and durability.

Our RO1 and RS7 Square Taper include tandem front and tandem rear cranks. Plus, the Middleburn X-TYPE crank arms have been designed with performance as a priority - the super lightweight arms can be fitted to a range of spiders for all types of riding. With a range of sizes from 160 - 180mm, Middleburn cranks are forged cast, polished and then available as silver or black anodised. You can find more information about them on this page. 

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