Choosing the right sized bike depends on the type of bike, your height, your riding style, and your preference. A correct fitting bike will be more comfortable, more efficient and more fun to ride. This bike size guide gives our customers general advice on choosing the right size. It is a guide only and we always recommend visiting one of our stores or contacting one of our experts. To get started, think about your style of riding, measure your height and use the links above for sizing on relevant bike types.
Measure your height
To find the correct sized bike you will need to measure your height and your inside leg. For your height, stand against a wall and mark the wall with a pencil so it’s level with the top of your head. Then measure from the ground up to the mark (having someone to help might make this easier). For your inside leg measurement, stand against a wall and using a book hold it in between your legs into your groin and make sure it’s flat against the wall. Measure the height from the book to the floor. (Again it might be easier to get a friend to help). If your height is on the cusp of the size range, your reach is often the deciding factor in which size to go for. To find out if you have short or long reach you will need to measure your ape index. This is your arm span minus your height. If you have a positive ape index then go for the larger size, or if you have a negative ape index go for a smaller size.
The type of bike
What type of bike you choose will affect the size bike you buy. 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. There is no definitive right or wrong size, it all comes down to personal preference and what feels comfortable.
How are bikes measured?
Bikes are measured by their seat tube length. This measurement is normally from the centre of the bottom bracket (BB) or the centre of the bolt that attached the crank arms. This differs by brand, some measure to the top of where the top tube meets the seat tube, or even the centre of the top tube. Mountain bikes are either measured in inches or descriptive sizes (small, medium etc). Road bikes are in centimetres or descriptive sizes where as Hybrid bikes can be any one of the three. Bikes also get longer as they go up in size (relative to the frame size) but different brands can be inherently longer or shorter than others.
Stand over height
Stand over height is how tall the frame is from the ground. Stand over height measurements are to the top of the top-tube. Ideally you want at least 2cm of clearance between you and the frame. In theory your stand over height is your leg measurement minus 2cm. It it worth measuring your inside leg with your shoes on so you can establish your stand over height. Should you need to jump off the saddle quickly, the clearance between you and the frame will prevent any injuries.
Mountain Bike Sizing Guide
We provide a suggested rider height for the various frame sizes below. 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. Always check the manufacturers measurements or visit a store to speak to a experienced member of staff. Always make sure you are able to stand over the frame with a minimum of 2cm gap between you and the top tube.
|Rider Height||Suggested Mountain Frame Size|
|Feet & Inches||Centimetres||Frame Size (Inches)||Frame Size|
|4’10” – 5’2″||148cm – 158cm||13″ – 14″||X-Small|
|5’2″” – 5’6″”||158cm – 168cm||15″ – 16″||Small|
|5’6″ – 5′ 10″||168cm – 178cm||17″ – 18″||Medium|
|5’10” – 6’1″||178cm – 185cm||19″ – 20″||Large|
|6’1″ – 6’4″||185cm – 193cm||21″ – 22″||X-Large|
|6’4″ – 6’6″||193cm – 198cm||23″ – 24″||XX-Large|
How are Mountain bikes measured?
Mountain bikes are measured from the centre of the bottom bracket (BB) to the top of the seat tube. Mountain bike top tubes will often slope down and join the seat tube lower than on road bikes. This is to give the rider more stand over height. It’s worth taking your inside leg measurement and comparing it to the manufacturers model.
Always check the manufacturers measurements or visit a store to speak to an experienced member of staff.
Women’s bike sizing
Women’s mountain bikes tend to be shorter in length, have narrower handlebars and smaller frame sizes. Women’s mountain bikes also have women’s specific saddles and often have their own colour scheme. They are measured in the same way from the centre of the bottom bracket (BB) to the top of the seat tube. Remember that women aren’t just restricted to women specific bikes as most bikes are unisex.
|Rider Height||Suggested Women’s Mountain Frame Size|
|Feet & Inches||Centimetres||Frame Size (cm)||Frame Size|
|4’10” – 5’2″||148cm – 158cm||13″ – 14″||X-Small|
|5’2″ – 5’6″||158cm – 168cm||15″ – 16″||Small|
|5’6″ – 5’10”||168cm – 178cm||17″ – 18″||Medium|
|5’10” – 6’1″||178cm – 185cm||19″+||Large|