Mountain Bike Sizing and Fit

What is the right size mountain bike for me?

Mountain bikers race along mountain pathway
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Use the sizing chart below to find the right sized mountain bike for you. If you know your height and inseam measurements, you should be able to determine what size frame will be most comfortable for you. Of the two measurements, height and inseam, inseam is more important.

Mountain bikes are generally measured in frame size (inches), which is the distance from the center of the crank to the top of the frame at the seat tube.

Mountain Bike Sizing Guide

Mountain Bikes - Finding the Right Size 
Your HeightYour Inseam LengthBike Frame SizeDescriptive Frame Size
4'11" - 5'3"25” - 27”13 - 15 inchesSmall
5'3" - 5'7"27" - 29"15 to 17 inchesSmall - Medium
5'7" - 5'11"29" - 31"17 to 19 inchesMedium
5'11" - 6'2"31" - 33"19 to 21 inchesLarge
6'2" - 6'4"33" - 35"21 to 23 inchesXL - Extra Large
6'4" and up35" and up23 inches and upXL - Extra Large


When buying a bike, fit is the most important factor when it comes to comfort—and the more comfortable you are, the likelier you are to keep riding. As such, it’s very important to pay attention to the size of the bike you are considering so that you buy the right one at the start. A bike that is too small will quickly grow uncomfortable and frustrate you. A bike that is too big is also uncomfortable to ride and can be dangerous as well if managing its size is a problem.

As you can see from the chart above, mountain bike frames are measured in inches.

Sizing goes from about 13-15 inches which is what someone on the small size—around five feet tall—might ride up to 21-23 inches, which is best suited to a taller rider, someone 6-2 and above.

In general, a bike will be approximately the right size if the top tube (the bar that goes between the seat and the handlebar) leaves approximately two or three finger space below your groin (i.e., the inseam of your pants) as you straddle your bike with your feet flat on the floor.

If there is no top tube, sit on the seat. You should be able to touch the ground with your feet, but only on tippy-toes, and even then maybe on one side or the other. Note that mountain bike frames are going to generally be smaller than road bike frames which is intended to make them easier for you to handle on rough terrain.

This may feel odd and uncomfortable as you sit in place on a bike, but it’s a natural riding position. If you are able to put both feet on the ground when you are sitting on the seat, the bike is too small or the seat is too low, or both.

Also, when sitting on the seat, your feet should be comfortable on the pedals and you should be able to reach the handlebars comfortably without either being scrunched too close together, or being stretched too far out as you lean forward to get them.

Until you feel fairly confident as to what size bike is going to be right for you, trying out a bike in person at your local bike shop is the best way to make sure you are buying a bike that fits you properly.

You’ll be able to try out a range of sizes to see what feels best. Plus, the experts there will be able to tell if the bike you are considering is too little or too big and recommend.

They’ll also know other adjustments that can be made to improve and fine-tune the fit of the bike even more when you’ve got the right one. These adjustments might include raising or lowering the seat, moving it farther back or more forward, and adjusting the height of the handlebars.

There is nothing more satisfying that zipping around on a bike that fits you perfectly. Such a bike becomes an extension of your own body and it’s definitely worth putting in the time and effort to find the one that is just the right size for you.