A Common Sense Guide to Bicycles

How to Measure a Full Suspension Mountain Bike

Full suspension mountain bikes are a newer class of mountain bikes, equipped with front and rear suspension, 26" tires and made from steel, aluminum or carbon fiber. While the rear suspension makes the bike more comfortable when riding off road, it adds weight and more moving parts to the bike. Each manufacturer has their own design for handling the rear suspension, but they all serve the same purpose- allowing the rear tire to move up and down and absorb shock from bumpy terrain. The frame size is determined by the length of the seat tube, even if it isn\'t a straight, continuous tube. The instructions below explain how to measure a full-suspension mountain bike.

Full-suspension mountain bike

Full-suspension MTB

Rider Charts

Once you know your bike's frame size, select it from the drop-down to see how tall riders should be to use this bike.


Center to Top (C-T) - This is the length of the seat tube, measured from the center of bottom bracket to top of the seat tube.

US (in) - Mountain bikes are measured in inches.

Frame Diagram

Full-suspension mountain bike frame with seat tube measurement highlighted

Measuring Instructions

  1. Identify the top of the seat tube, where the seat clamp holds the seat post.
  2. Identify the center of the bottom bracket (it's the axle that holds the crank arms together).
  3. Measure the distance between the two points (C-T) - this is the length of the seat tube.
  4. Record your measurement in both centimeters (cm) and inches (to the nearest half-inch).
  5. Select your bike size from the drop-down on the right to see a rider height chart.