Bike Size Guide

CHOOSING THE RIGHT SIZED BIKE

Making sure you choose the correct frame size is of paramount importance when buying a new bike. The correct fitting bike will be more comfortable, more efficient and more fun to ride.

We know that choosing the right sized bike can be a confusing experience, even for the most experienced cyclists – the right size frame depends on the type of bike, your height your riding style and your preference.

This guide gives our customers general advice on choosing the right sized bike. It is a guide only and we always recommend visiting our store or contacting one of the experts in shop on 01302 322888 if in doubt about the size bike you need.

Read our introduction to bike sizes below, or go straight to the sizing chart for the type of bike you are purchasing:

How are bike frames measured

Bike sizes are determined by the frame size, based on the length of the seat tube. Most manufacturers measure from the centre of the crank axle (bottom bracket) to the top of the seat tube, where the seat post is inserted.

Unfortunately, some manufacturers measure their models from the intersection of the top tube and seat post to the crank axle, which can throw out some of the sizings, so if ever in doubt consult one of our experts in store.

Manufacturers quote sizes in different ways, some quote the size in centimetres, some in inches and some as a frame size (such as Small, Medium, Large, etc).

Although the size of frames are based on the measurement of the seat tube, it’s not just the seat tube that changes depending on the size – the entire frame changes in proportion to the frame size.

Matching you to the right size bike – what’s your height?

To help our customers choose the right size bike we provide a suggested height for the various frame sizes available.

In order to accurately match the correct frame to your height it’s essential you measure your height accurately!

To best measure your height, stand against a wall with your shoes off. Keep your legs together and your shoulders back. Carefully place a pencil on top of your head and mark the wall – for best results get a helper to mark the wall for you. Then measure the mark on the wall with a tape measure.

If your height is on the cusp of the range your reach is often the deciding factor in which size to go for. To find out if you have a short or long reach measure your Ape Index (your arm span minus your height) – if you have a positive ape index then go for the larger size, if you have a negative ape index go for the smaller size.

Stand over height

Stand over height is the clearance between the top of the top tube (also known as a cross bar) and the bottom of your crotch. It’s important that you have adequate clearance in this area to avoid contact when you’re stopped and astride the bike. For road and hybrid bikes 1 to 2 inches of clearance is required, mountain bikes require 2 to 4 inches.

The sizes we recommend in our sizing charts take stand over height into consideration. So if you’ve got a close to average inside leg measurement our recommendations will be fine. If you have a short or long inside leg measurement in relation to your height we recommend talking to us in store to ensure you purchase the best fitting bike.

What type of bike and what type of riding?

Different types of bikes are sized in different ways. A 58cm road bike will be quite a different size to a 58cm time trial bike – so it’s important you look at the sizing chart for the type of bike that you are purchasing.

Road, triathlon and time-trial bikes are the most important to size correctly. The reach can determine feel and the frame size required, stand over height is not as important.

The type or style of riding that you do will also affect which size you need. For example a mountain biker that wants to ride more aggressively and would like a more manoeuvrable bike may prefer a size smaller than they would normally take. Likewise a cross country racer that is looking for a flatter and speedier mountain bike may prefer a size larger than they would normally take. Basically there is no right or wrong when it comes to size – choosing the right bike does come down to personal preference and what you feel is comfortable and right for the riding that you do.

Mountain bike sizing chart (hardtail & full suspension)

Rider Height Frame Size Suggested
Feet and Inches Centimetres Inches Size
4' 10" - 5' 2" 148 - 158 13 - 14 XS
5' 2" - 5 '6" 158 - 168 15 - 16 S
5' '6" - 5' 10" 168 - 178 17 - 18 M
5' 10" - 6' 1" 178 - 185 19 - 20 L
6' 1" - 6' 4" 185 - 193 21 - 22 XL
6 '4" - 6' 6" 193 - 198 23 - 24 XXL

 

Women's mountain bike sizing chart (hardtail & full suspension)

Rider Height Frame Size Suggested
Feet and Inches Centimetres Inches Size
4' 10" - 5' 2" 148 - 158 13 - 14 XS
5' 2" - 5 '6" 158 - 168 15 - 16 S
5' 6" - 5' 10" 168 - 178 17 - 18 M
5' 10" - 6' 1" 178 - 185 19+ L

 

Road bike sizing chart

Rider Height Frame Size Suggested
Feet and Inches Centimetres Centimetres Size
4' 10" - 5 '0" 148 - 152 47 - 48 XXS
5' 0 "- 5' 3" 152 - 160 49 - 50 XS
5' 3" - 5' 6" 160 - 168 51 - 52 - 53 S
5 6" - 5' 9" 168 - 175 54 - 55 M
5' 9" - 6' 0" 175 - 183 56 - 57 - 58 L
6' 0" - 6' 3" 183 - 191 58 - 59 - 60 XL
6' 3" - 6' 6" 191 - 198 61 - 62 - 63 XXL

 

Women's road bike sizing chart

Rider Height Frame Size Suggested
Feet and Inches Centimetres Centimetres Size
4' 10" - 5' 1" 147 - 155 44 - 45 - 46 XXS
5' 1" - 5' 3" 155 - 160 47 - 48 - 49 XS
5' 3" - 5' 5" 160 - 165 50 - 51 - 52 S
5' 5" - 5' 8" 165 - 172 53 - 54 - 55 M
5' 8" - 5' 10" 172 - 180 56 - 57 L

 

Hybrid bike sizing chart

Rider Height Frame Size Suggested
Feet and Inches Centimetres Inches Size Centimetres
4' 10" - 5' 1" 147 - 155 13 - 14 XS 47 - 49
5' 1" - 5' 5" 155 - 165 15 - 16 S 50 - 52
5' 5" - 5' 9" 165 - 175 17 - 18 M 53 - 54
5' 9" - 6' 0" 175 - 183 19 -20 L 55 - 57
6' 0" - 6' 3" 183 - 191 21 - 22 XL 58 - 61
6' 3" - 6' 6" 191 - 198 23 - 25 XXL 61 - 63

 

Triathlon and Time Trial bike sizing chart

Rider Height Frame Size Suggested
Feet and Inches Centimetres Centimetres Size
5' 0" - 5' 3" 152 - 160 49 - 50 XS
5' 3" - 5' 6" 160 - 168 51 - 52 S
5' 6" - 5' 9" 168 - 175 53 -54 M
5' 9" - 6' 0" 175 - 183 55 - 56 L
6' 0" - 6' 3" 183 - 191 57 - 58 XL
6' 3" - 6' 6" 191 - 198 60 - 61 XXL

 

Jump and Trial bike sizing

As a general rule Jump and Trial bikes are one size fits all; catering for people from heights of 4' 10" - 6' 4" (148cm - 193cm).

Folding bike sizing

As a general rule folding bikes are one size fits all catering for people from heights of 4' 10" - 6' 4" (148cm - 193cm).

BMX bike sizing chart

Rider Age or Height Wheel Size Suggested
Feet and Inches Centimetres Age Inches
3' 7" - 4' 0" 110 - 122 5 - 7 years 16
4' 0" - 4' 10" 122 - 147 7 - 11 years 18
4' 10" - 6' 4" 147 -