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Buying a new mountain bike can be confusing and overwhelming. There are so many options out there and it’s hard to know where to start.

Choosing the right size mountain bike is one of the most important decisions you need to make. Buying the proper size is crucial and is often overlooked.

Mountain bikes are designed for bike riders looking to experience durable and rugged cycling.

Therefore it is important to have the right bike for your body type in order to avoid discomfort, which will result in poor performance and possible injury.

The wrong-sized mountain bike can lead not only cause physical pain but also mental anguish because you are constantly adjusting yourself while riding or feeling like you’re about fall off at any moment!

The following mountain bike size chart and information will help you make the right decision if you’re in the market for a new mountain bike that is sized properly for you.

red mountain bike

What size mountain bike should I get for my height?

When choosing a mountain bike, you will need to know your height. Depending on how tall you are, you can reference a sizing chart to see which bike is recommended for you.

Sizing charts for mountain bikes like the one in this article, are generally a guide to recommending the properly sized bike for you based on your height.

As not all mountain bikes are the same, you should also reference the manufacturer’s sizing chart which will be specific to that brand, make, and model.

For example, if you are 5 foot 6 inches tall, you will need a mountain bike with a recommended frame size of 17 – 18 inches.

Mountain Bike Size Chart

mountain bike size chart

You can also use the following steps and formula to calculate the properly sized mountain bike for you.

Step 1. Measure the height from the ground to where your legs come together or inseam. Make sure you are not wearing shoes and keep your legs 6 – 8 inches apart.

Step 2. Take that measurement and multiply by 0.66.

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For example, let’s say you measured 73 centimeters for your inseam.

73cm x 0.66 = 48.18 cm

You will need a mountain bike frame size of 48 cm or 19 inches.

If you don’t want to do the math, use the following chart.

How do you size a mountain bike?

Most mountain bikes are given a frame size of small (S), medium (M), large (L), extra-large (XL), and extra-extra-large (XXL).

The frame size is calculated by measuring the length of the seat tube. This length is taken from the center of the front chainring to the top of the tube where the seat post goes in.

Different manufacturers will have varied frame designs so the frame size of S,M,L is used for generic sizes.

Mountain bike geometry

Mountain bikes come in many shapes and sizes. However, not all mountain bike geometries are created equal. The geometry of a mountain bike affects the way it handles various terrain types as well as how comfortable you will be while riding it.

mountain bike geometry

Red – Wheelbase

Blue – Stack

Cyan – Bottom bracket height

Yellow – Chainstay length

Green – Head angle

Pink – Reach


A mountain bike’s wheelbase refers to the distance from one side of the wheel (front or back) to another point on that same side of the wheel when it reaches its furthest point forward/backward in relation to its centerline. The measurement is taken at either axle or rocker arm.


Mountain Bike Stack is a term used to describe the amount of “stack” or height difference between your saddle and handlebars.

The higher the stack, the more stretched out you will be on your bike. This style is popular with cross-country mountain bikers who prefer to ride in an upright position with their weight distributed evenly on both feet.

Mountain bike stacks can range from around 30mm all the way up to 130mm or more for downhill racers looking for maximum control over their bikes.

mountain bike on the beach

Bottom bracket height

Mountain bike bottom bracket height refers to the distance between the ground and where your pedal crank arm is. The standard mountain bike bottom bracket heights are 68mm, 73mm, and 80mm.

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Bikes with a higher mountain bike bottom bracket will generally make it easier for you to climb steep hills because they have a shorter wheelbase.

Bikes with lower mountain bike bottom brackets are more comfortable on flat terrain but may be less stable when descending at high speeds or taking sharp turns at speed.

Chainstay length

Mountain bike chainstay length is a key part of the geometry of any mountain bike frame. It’s important to choose the right size for your body and riding style.

The shorter you go, the more nimble your bike will be but it will also feel less stable at high speeds or when going over rough terrain.

The longer you go, the easier it will be to pedal and control your speed, but it may also feel sluggish in tight corners because of its larger turning radius.

There are three factors that determine how long your mountain bike’s chainstay needs to be: the size of the wheel, the type of suspension, and where you’re riding.

black mountain bike on grass

Head angle

The angle of your mountain bike’s head tube is a critical component in determining how stable and maneuverable your ride is.

The classic measure for the head angle is between 66° and 68°, but that number can vary depending on the type of terrain you’re riding and what kind of frame geometry you prefer.


Reach measurements are an important aspect of mountain bike geometry. It is often reported as the distance from the center of the handlebars to the top tube, or how far you reach forward for a given crank length.

This measurement is usually expressed in centimeters and can be found on all major bicycle manufacturer’s websites.

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