Bike Sizing Guide: All of our Tips & (All)Tricks
Here is a question that comes up often! Indeed, investing in a new bike is not to be taken lightly and you cannot afford to "feel your way" on this point. A bike that suits your morphology will provide you with comfort, efficiency, and maneuverability, whereas, on the contrary, a poorly adapted bike will quickly cause discomfort and pain that could turn your favorite hobby into a nightmare!
There are many brands on the market today, and each tends to take measurements in its own way, so we will try to guide you to find the bike size that suits you best.
What does the size of bikes correspond to?
Historically, all bike frames had a straight top tube, and the length of the seat tube defined the size of the bike. This notion has become blurred with the appearance of new geometries: sloping road bike frames (inclined top tube), full-suspension mountain bikes, city bikes, etc...
Indeed, some manufacturers now use international sizes (S, M, L...), some continue to indicate their sizes in "actual sizes" (which corresponds to a virtual measurement on a sloping frame), while others have started to indicate sloping sizes. Therefore, you need to pay attention to how the manufacturer indicates its measurements to ensure you find the bike that suits you best.
What measurements should you take for your mountain bike or bike size?
The essential measurements for choosing your new bike are height, inseam height, and arm span.
Start by measuring your inseam height. To do this, stand barefoot with your back against a wall, feet slightly apart (about 20 cm), and heels in contact with the wall. Then place a rigid support, a book will do, in contact with your perineum (the 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 floor to the top of the book. Multiply the value obtained by 0.665 to get an actual road bike size in centimeters or by 0.226 to get an actual mountain bike size in inches.
If, after your calculations, you fall "between two sizes," the upper part of your body will be decisive in choosing one size or the other. Indeed, the length of your torso and arms will determine the adequate distance from the handlebars. To do this, it is necessary to define your "APE index," which is obtained by subtracting your height from your "arm span" (length from one end of an arm to the other when you have your arms spread out). If the value obtained is greater than zero, you should take the larger bike size, and conversely, take the smaller size if the value is less than zero.
Bike size charts
Bike sizes are expressed in different ways. For Road, Gravel, and Cyclocross bikes, the size will be indicated in centimeters (cm). For mountain bikes, sizes are indicated in inches (in) and/or in standard sizes (XS to XXL). Regarding city bikes, their sizes can be expressed in inches or cm. Refer to your height and inseam to find the size that suits you best.
| 152 – 160cm | 68cm | 48cm | 14in | XS |
| 161 – 162cm | 73cm | 48cm | 14in | XS |
| 163 – 164cm | 74cm | 48cm | 14in | XS |
| 165 –166cm | 75cm | 50cm | 14in – 16in | XS – S |
| 167 – 168cm | 76cm | 50cm | 16in | S |
| 169 – 170cm | 77cm | 52cm | 16in | S |
| 171 – 174cm | 79cm | 52cm | 16in – 18in | S – M |
| 175 – 178cm | 81cm | 53cm | 18in | M |
| 179 – 180cm | 82cm | 53cm | 18in | M |
| 181 – 182cm | 84cm | 54cm | 18in | M |
| 183 – 184cm | 86cm | 55cm | 18in – 21in | M - L |
| 185 – 187cm | 87cm | 56cm | 21in | L |
| 188 – 189cm | 90cm | 57cm | 21in | L |
| 190 – 192cm | 91cm | 60cm | 21in – 22in | L - XL |
| 192 – 194cm | 92cm | 60cm | 22in | XL |
| 194 – 198cm | 93cm | 60cm+ | 22in – 24in | XL -XXL |
| 198 – 200cm+ | 94+cm | 60cm+ | 24in | XXL |
Select your height (cm):
Your height: 170 cm
Find the bikes available in your size:
*The bike sizes indicated in this table are for informational purposes. Each bike brand has different sizes for each frame. For more information, refer to the technical specifications of the bike of your choice.
How to choose the size of a child's bike?
Children's bike sizes are defined by the size of the wheels; you will find a table on our products indicating the corresponding child sizes. The first sizes start at 12 inches, including pedal-less bikes called balance bikes. The balance bike is ideal for beginners to learn balance.
Children grow very quickly, and some parents tend to want to get the largest possible bike to extend its lifespan. We strongly advise against this practice because the child may become frightened on a bike that is too big for them and quickly become discouraged. There is also a risk to their safety.
> Read our complete tutorial to choose the size of a child's bike
What wheel size should you choose for your bike?
Since the birth of the mountain bike in the 1980s, all bikes were delivered with 26-inch wheels. From 2009, manufacturers developed the 29-inch standard and then an intermediate standard, the 27.5 inches. But how to choose?
- If you prioritize maneuverability and agility, we recommend choosing a 26”. Moreover, these wheels being the smallest, they will also be the lightest.
- If, on the contrary, you are looking for comfort and performance, we will guide you towards the 29”. Indeed, the larger tire section will tend to smooth out the terrain's irregularities. Then, the large diameter of the wheels provides a reduced attack angle (angle between the wheel and the ground) that will allow you to overcome obstacles more easily. Finally, when rolling, 29” wheels generate more centrifugal force and will therefore be more stable than 26” wheels. Moreover, taller people will find geometries more suited to them with these wheels. However, to achieve equivalent rigidity, these wheels are heavier and will therefore have more inertia when accelerating.
- If you are a person of compromise and you are looking for the best balance between maneuverability, comfort, and performance, manufacturers have also thought of you with the revival of the 27.5”. Historically known in France as 650B, this wheel standard was at the time used on leisure road bikes. It now equips a wide range of bikes from all manufacturers.
These tips should be taken with some measure because your practice, your morphology, your level, and the terrain are all parameters to consider when choosing the wheel size for your bike. For example, a bike with 29” wheels, and thus a high center of gravity, will not suit a beginner of small stature at all.
Find the perfect position on your bike with a postural study
Our bike postural study uses digital tools to ensure comfort and performance.
For this, the Bioracer Motion system stands out with a simultaneous analysis of both profiles of the cyclist, for a unique overview of their movements, symmetry, and stability.
It is a valuable aid for the operator, who nevertheless remains at the heart of the system.
You thus have access to the best in static and kinematic postural study thanks to high-end equipment and a cutting-edge capture system.
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