Bike Sizing Made Easy: All of our Tips & (All)Tricks

Choosing the right size bike is directly related to the amount of enjoyment you'll feel riding your bike. Too small? You'll feel squeezed. Too big? You'll feel like you don't have control over your bike. The right size will make you feel like you become one with the bike: more comfort, more control, more power, more safety. Usually, bike brands use two types of sizing: letters or numbers (For example Canyon uses XS, S, M,... whereas Cannondale uses 50, 52, 54,...). The size of the bike is determined by the size of the frame.

Easy enough right? If you consider that every manufacturer doesn't measure its frames the same way, not really. A Trek size 54 and a BMC size 54 might have a 10cm difference between them.

Not sure what type of bike suits you?

If you are unsure of what type of bike woud be best suited to your need, we also provide additionnal guides to help you find your dream bike! Check out these giudes:

Your roadbike fitted to perfection
How to choose your MTB
The do-it-all Gravel bikes
If you are looking to get an e-bike
Your kid's first bicycle

What do bike sizes correspond with?

On every bike product page you'll find documentation detailling how to understand the measurements given to you by the manufacturer. We try to provide you with equivalent in centimeter to help you make the right choice.

Historically, all bicycle frames had a right upper tube and the length of the seat tube defined the size of the bike, but this notion has become outdated with the appearance of new geometries: sloping road bike frames (inclined top tube) , full-suspended MTBs, city bikes, etc...

How to measure myself?

The first step in choosing a frame is to measure yourself before even beginning to search for a bike. There are 3 key elements you should take into account: Your height, the length of your inside leg & your armspan or reach. The length of your inside leg will help us determine the length of the seat tube and the reach will help us determine the right length of the top tube.

Start by measuring your inside leg height. For this, stand upright against a wall, bare feet slightly spread (about 20 cm) and heels well in contact with the wall. Place a rigid support (a book will do), in contact with your perineum (muscle that is in contact with the saddle when you are on the bike). Then, with the help of another person, take the measurement from the ground to the top of the book, then multiply the value obtained by 0.665 to obtain a road bike's real size in centimetres or by 0.226 to get an actual MTB size in inches.

Use this formula: inside leg length*0.665=frame size you need.

If you end up in between two sizes, you should most probably opt for the smaller one as it will fit you better. But to be sure, you can measure your reach: put your back against a wall and, with the help of someone else, measure your armspan from finger to finger. Then use this formula: height in cm-armspan in cm=APE index. If your APE index is above 0 it means you should go for the bigger size, otherwise go for the smaller size.

How to choose a child's bike size?

Children bike sizes are defined by the size of the wheels. You will find a chart indicating the child size correspondences on our products. The first sizes start at 12 inches, including bicycles without pedals that are called dandy horse .

Children grow up very quickly and some parents tend to choose the biggest bike in order to prolong its durability, however, we strongly discourage this practice because the child may be afraid of a bike too big for them and quickly become discouraged. Their safety is also at risk.

> Read our complete tutorial to choose the size of a child's bike

Which wheel size to choose for your bike?

Since the birth of MTBs in the 80s, all bicycles have been delivered with 26-inch wheels. As of 2009, manufacturers have developed the standard 29-inch, then an intermediate standard, the 27.5-inch. But which one should you choose?

If you prefer manoeuvrability and liveliness, we advise you to take a 26". Besides, these wheels being the smallest, they will also be the lightest.
If, on the contrary, you are looking for comfort and efficiency, we guide you towards the 29". In fact, because the tire section is larger, the tire's suspension effect will tend to erase the terrain's roughness. Moreover, the wheel's large diameter provides a reduced angle of attack (angle between the wheel and the ground), which makes you able to cross obstacles more easily. Finally, by rolling, the 29" wheels will generate more centrifugal force and will therefore be more stable than the 26" wheels. Besides, taller people will find geometries at their size more easily with these wheels. However, in order to obtain an equivalent stiffness, these wheels need to be heavier and will consequently have more inertia at recovery.
If you are don't mind compromises are looking for the best balance between manoeuvrability, comfort and performance, manufacturers have also thought about you by recreating the 27.5". It now equips a wide range of bikes among all manufacturers.

These tips are to be taken with some caution because your practice, your morphology, your level and the terrain are all parameters to be taken into account in the choice of your bike's wheels size. For example a bike with 29" wheels, that is to say a high centre of gravity, won't work at all for a small beginner.

Find the perfect position on your bike with a postural study

Feeling just right on your bike is essential to riding better and more efficiently.

If you feel pain when riding your bike it means your position, the size of the bike or your fit is not good.

Feeling pain when riding is not normal and you should consider asking the relevant experts for advice. A bikefit is the best way to find what position is right for you, meaning the most comfortable and the most power output efficient.