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Bike Size Guide

We appreciate choosing the right size bike can be tricky, especially when buying online. However with a few prior measurements and the information/video below it should be simple. If you’re still unsure, you can speak with one of our expert sales team on live chat, email or phone.

How are bike frames measured

Bike sizes are determined by the seat tube length. This is the measurement from the centre crank axle bolt
(bottom bracket) to the top of the seat tube.
Seat tube diagram

Choosing the right size for you

To help you choose the right size bike, each product page suggests a height range for the various frame sizes available.
To make sure you choose the right size, we recommend you measure your height as follows:
Bike Size HeightBike size arm span
  • Stand against a wall with your shoes off
  • Keep your legs together and your shoulders back
  • Place a pencil flat on top of your head and mark the wall
  • Measure the distance from the mark on the wall to the floor
If you’re on the limit of two sizes and can’t decide, you need to measure your reach:
  • Measure your arm span. Hold your arms out and measure from finger tip to finger tip across the top of your chest
  • To find out whether you have a short or long reach calculate your “Ape Index” (arm span minus height)
  • If you have a positive Ape Index then go for the larger size. If you have a negative Ape Index then go for the smaller size. 
All of our sizes take into account stand over height (clearance between the top tube and your crotch area) and allow for 1 to 2 inches clearance.