Bike Sizing Guide

In order for your bike to be as comfortable and efficient as possible, it needs to be the correct size. Please be aware that personal preference can come into play; experienced cyclists may prefer a slightly smaller or larger frame than suggested. For expert bike sizing advice please do not hesitate to e-mail us on

What to measure?

The two main measurements needed to correctly size a bike is your height and inside leg. The easiest way to measure your own height is to stand up straight against a wall (with your shoes off) and make a small pencil mark, level with the top of your head, on the wall. Using a tape measure you can then find your height.

To measure your inside leg, stand with your legs approximately shoulder width apart with your shoes off, then measure from your foot to your crotch. Once again, you can always make a small pencil mark on a wall and measure its height. Your inside leg measurement is taken to ensure your standover height is adequate – this is the distance between the toptube and your crotch. It’s generally suggested that at least 2 inches of clearance provides you with enough room to stand off the pedals when required.

How are bikes sized?

Adult bikes are measured by their frame size. This is the length of the seat tube, which is generally measured from the centre of the crank axel to the top of the seat tube, although some manufactures only measure as far as the top tube join. Most road bikes are measured in centimetres, whereas mountain bikes are measured using inches (with very few MTB brands using centimetres).

Kids’ and junior bikes are measured using their wheelsize; kids’ and junior bike sizes range from 12 inch to 24 inch wheels. Bikes with 26, 27.5 or 29 inch wheels are classed as adult bikes.

Hardtail Mountain Bike

When riding off-road it is important to have a slightly smaller frame than you would for normal road riding. This is for 2 reasons, firstly to increase the amount of clearance you have over the crossbar to a minimum of 3 inches and secondly, a smaller frame will handle better over more challenging terrain. This will put you in a slightly more forward position with seat-post height extended.

Full-Suspension Mountain bikes

The range of frame sizes available for full suspension models is smaller than hardtail bikes. More than any other discipline, full suspension mountain bike sizing is down to personal preference. Some riders prefer a smaller frame as this can improve handling on technical trails.

Hybrid Bikes

When riding a hybrid bike, only 1-2 inches of clearance is required from the crossbar/top tube, placing you in a comfortable and efficient position. Due to the style of Hybrid bikes your riding position will be slightly more forward than compared to a mountain bike. For suspension seat-post models take 1 inch off the frame size you require.

Road Bikes

Sizing is all-important here as the rider is seated in a straight aerodynamic position. Only 1-2 inches of clearance over the crossbar/top tube is needed. Road bike sizing can vary by manufacturer so it’s worth calling our sales team for advice if you are unsure.

Kid’s & Junior Bikes

Kid’s and junior bikes use 12” to 24” wheels. Some younger children prefer to learn on balance bikes to gain experience. Once the rider is confident on a bike, they only need to have the ball of their foot on the floor to maximize growing room and ensure safety. Ideally the rider should have a few inches clearance over the crossbar to make safe stopping easy and allow for maximum manoeuvrability.

Personal Choice

The tables above are based on measurements and intended as a general guide only. Your riding style and personal choice can effect bike sizing and some cyclists do prefer a slightly smaller or larger frame than is suggested. We’re always on hand to chat about bike sizing, just give us a e-mail on or speak to us on Live help.