Crank arm shortening


  • appropriate size drill - 33/64" (or 13mm) for 9/16" threads (you may be able to get away with a 1/2" drill, but use a 33/64" or 13mm drill if you've got one);
  • drill press (a good milling machine is even better).

Note: you must shorten the cranks by at least 23mm, so a 175mm crank will become at most a 152. This makes it difficult to produce a 160mm crank as you need to start with 180mm cranks, which are hard to come by, particularly in a design suitable for shortening.

Further information

Old LX cranks

I shortened some old 175mm LX cranks down to 140mm for use on my daughter's bike:

I would not recommend shortening these cranks for adult use as the crank arms narrow down. As a result, there is less meat around the new pedal hole. This is not a problem for a 30kg rider.

388g for 140mm short crank arms:

One the bike:

Truvative FiveD cranks

I've got some Truvative FiveD cranks on my tandem and they look like perfect candidates for crank arm shortening. The crank arm is a consistent width and thickness and remains perpendicular to the bottom bracket spindle for a distance that means you could shorten these down to perhaps 130mm.

I got a second hand pair of FiveD 175mm cranks and shortened them to 150mm. Worked well.

Shortened FiveD crank

Other suitable cranks

Backview of Shimano Deore crank arm
  • Truvaitiv Firex and Isoflow
  • Suntour XCT - plenty of meat with non-tapered arms.  Looks like you could quite short with these.
  • FSA

Backview of FSA crank arm

Not-suitable cranks

Three basic categories of cranks are not suitable for shortening:

  • cranks with hollow crank arms. eg. Shimano Hollowtech II cranks, Stylo OCT, SRAM higher end models;
  • cranks which narrow down too much or which lack sufficient material at the back of the crank arm for the pedal thread;
  • carbon fibre crank arms;

Related articles:

AC Mini-Le cranks

Crank is made from aluminium and uses a square taper bottom bracket.

Truvativ 5D cranks

These came on my Apollo Synchro 26 tandem.

165mm lightweight cranks

As my kids grow, I'm needing progressively longer cranks, but unfortunately, my tallest kid is still too short for commonly available 170mm cranks. At the moment, a set of 160mm cranks would be perfect. ...

Fox Float R shock shortening


Shimano XT 165mm crankset

Quick facts:

Shortening spokes

Here's how I do it (in this example I'm shortening a titanium spoke, but the procedure for stainless steel spokes is the same):