Bicycle size guide for Mountain

Choosing the right size of your mountain bike is key to enjoying a comfortable, efficient and safe ride, both on trails and technical routes. In this guide you will find everything you need to know: from how to measure your body correctly to equivalence tables for height and inseam, advice depending on the type of use and differences between geometries. If you are looking for your first MTB or want to improve your posture on the saddle, here you will answer all your questions to find your ideal size.

Why is it important to choose the correct size?

Riding a mountain bike with the right size makes all the difference. A correct size allows you to make the most of your energy, improve your posture and maintain a constant pedaling without straining, even on uneven terrain. In addition, it helps prevent knee, back or neck discomfort and reduces the risk of injuries in the medium and long term. Whether for routes of trail, technical outings or simply enjoying the countryside on weekends, an MTB adapted to you offers you more control, efficiency and comfort on each ride.

Bicycle size chart for Mountain

Equivalence by height and inseam

To know which size of bicycle you need, the most accurate method is to combine your height with your inseam measurement. This allows you to calculate the ideal seat tube length and choose the frame that best fits you.

Size chart in cm and inches (S, M, L, XL...)

Below, you can check a reference table with the recommended sizes according to your measurements. Remember there may be small variations depending on the geometry and brand of the bicycle.

Height (cm)	Inseam (cm)	Frame Size (cm)	Standard Size	Size in Inches
150 – 160	65 – 70	47 – 49	XS	18.5” – 19.3”
160 – 170	70 – 75	50 – 52	S	19.6” – 20.4”
170 – 175	76 – 80	53 – 54	M	20.8” – 21.2”
176 – 182	80 – 85	55 – 56	L	21.6” – 22.0”
183 – 190	85 – 90	57 – 59	XL	22.4” – 23.2”
190+	90+	60 – 62	XXL	23.6” – 24.4”

Already know your size? Explore available Mountain bicycles directly

Bikes Size S Bikes Size M Bikes Size L Bikes Size XL

How to calculate your ideal size with a formula

If you don't want to rely solely on a chart, you can calculate your bicycle size using a simple formula based on your inseam length. You only need a measuring tape and to follow these steps:

Step 1: measure your inseam

Stand barefoot against the wall, with your legs straight and about 15 cm apart. Use a book or level between your legs, simulating a saddle, and measure from the floor to the superior part of the book. That is your inseam in centimeters.

Step 2: apply the formula

Once you have the measurement, multiply that number by 0.66 to get the ideal frame size (in cm):

Frame size (cm) = Inseam (cm) × 0.66

Practical example

If your inseam measures 78 cm:

78 × 0.66 = 51.48

The recommended size would be a frame of approximately 51-52 cm, equivalent to a size S or M depending on the range of bicycles Specialized.

What if you are between two sizes?

If the calculation gives you an intermediate value, take your riding style into account: for greater comfort, choose the larger size; if you want a more aggressive and sporty ride, choose the smaller one.

Differences between Mountain Bike Geometries

The geometry of a mountain bike directly influences its behavior and the rider's experience. The bikes of Cross Country (XC) They have compact geometries and tighter angles, which favors agility and efficiency on climbs. The Trail and All Mountain They opt for a more relaxed geometry, with greater reach and open angles, offering control and comfort on descents. In the Enduro and the Downhill, the bikes feature long frames, very open head angles and telescopic seatposts, maximizing stability and control on technical terrain and demanding descents.

How Sizes Relate to Brands

Sizes in Trek, Orbea, Specialized, Canyon, etc.

Bicycle sizes may vary slightly between brands, even if in theory they are the same. A size M in a Trek may feel a little different than an M in Orbea or Canyon, due to differences in frame geometry, reach and stack.

For example, Trek usually offers a balanced geometry, while Canyon It tends to have slightly longer and more aggressive frames, designed for more aerodynamic pedaling. Orbea bet on versatility and comfort, and Specialized adjusts each size to offer a more personalized “fit” depending on the model (as happens with its line Tarmac or Roubaix).

Therefore, before buying a specific bike, the ideal is to consult with our specialists. The same height may require a different size depending on the exact model of the bike.

Explore Mountain bicycles by brand

Orbea MTB bikes Specialized MTB Bikes Scott MTB Bikes Mondraker MTB Bikes Giant MTB Bikes Lapierre MTB Bikes Trek MTB Bikes Canyon MTB Bikes

Size guide for other brands

Sizes Trek Sizes Giant Sizes Cannondale Sizes Specialized Sizes Scott Sizes Orbea Sizes BMC

Sizes Berria Sizes Colnago Sizes Cube Sizes Felt Sizes BH Sizes Cervélo Sizes Lapierre

Sizes Canyon Sizes Mondraker Sizes Bianchi Sizes Merida

Frequently Asked Questions

Not exactly. Although they may seem similar, the geometry and use are different. A size M on a road bike does not always correspond to an M on a gravel or MTB. That’s why it’s important to consult the specific charts for each type of bike.

Yes. The shape and geometry of the frame (aero, endurance, compact, sloping, etc.) can make two bikes with the same “official” size feel very different. It’s always recommended to check the geometry and reach of the specific model you’re going to buy.

Relying only on height without measuring your inseam.
Choosing by intuition without consulting charts or formulas.
Settling for a size just because “it’s what’s available.”
Not considering the use: comfort and type of routes also matter.
Ignoring the possibility of adjusting components (stem, seatpost, etc.) if you’re between two sizes.