Bike Sizing Guides
Choosing the bike size depends on a number of factors, including the type of bike you’d like, your height, your riding style, and your personal preference. A correct fitting bike will be more comfortable, more efficient and more fun to ride. Our bike size guides are designed to help give you general advice on how to choose the right bike for you. They are intended as a guide only.
To get started, think about your style of riding, measure your height and use the links below 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. To find your height, stand against a wall and mark the wall with a pencil where 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 upright with your back against a wall. Place a book or a ruler between your legs, level with your crotch and make sure it's flat against the wall. Measure the height from the book (or ruler) to the floor. (It might be easier to get a friend to help).
If your height is on the cusp of the size range in our guides, 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.
Choosing the size and style of bike
The size of the bike is also affected by the type of bike and your style of riding. For example if you’re a keen mountain biker who loves the aggressive, nippy style then you’re likely to take a size smaller than normal. If you’re more of a cross country racer that is looking for a flatter and speedier mountain bike you may prefer a size larger than you would normally take.
There is no definitive right or wrong size; it all comes down to personal preference and what feels comfortable for you
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 attaches 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 is worth measuring your inside leg with your shoes on so you can establish your stand over height more precisely. If you ever need to jump off the saddle quickly, the clearance between you and the frame will prevent any injuries.