What Size Mountain Bike Do I Need?

Buying a bicycle has never been easier – and there’s never been such a huge amount of high-quality bikes available. That’s definitely good news, but if you want to be 100% certain that you’ll end up satisfied with your purchase, there are some things you should keep in mind.

We’re talking about the basics – and when it comes down to it, there’s nothing more fundamental than getting a bike that is the right size.


What Size Mountain Bike Do I Need

Purchasing a new mountain bike is always exciting – and although it can sometimes turn into a chore, surfing the web and looking for the perfect bike has a unique charm of its own.

The anticipation and wondering about how a new mountain bike will handle, how it will glide over trails and bumps will push you to find a great product – but even if you get the greatest bike in the world, it will be all for nothing if it doesn’t fit you.

Man Riding a Mountain Bike

Choosing a bike that’s the right size is imperative. That much is obvious – but it often goes without saying, which is to say, without thinking. Making a mistake here can be a huge downer – a potentially expensive one, at that, but these mistakes can easily be avoided.

If you want to make absolutely sure that such mistakes don’t happen, our short mountain bike sizing guide is at your disposal.


The Geometry of Mountain Bikes

Before we get down to the concrete details, let’s take some time to deal with bike geometry. Refreshing your knowledge of this topic is important – and it will give you a more solid footing upon which to make your decision. Mastering the basics will mean that you won’t have to refer to guides and constantly re-check and second guess your decision.

The Size of the Frame

Frame sizes are usually listed either descriptively – XS, S, M, L and so forth, or measured by inches. Obviously, small, medium and large don’t offer enough information for you to base your decision on – so you should refer to the actual measurements.

Mountain Bike on Stand with Grassy Background

Simple enough, right? Unfortunately, that’s not the case. Frame size is measured by the length of the seat tube – but the actual method of measurement varies from manufacturer to manufacturer. In truth, there is no universally accepted method of measuring seat tube length.

But there’s no reason to be alarmed – we’ll explain how to check if the frame size suits you in the second part of the article.

The Top Tube

Another important factor to consider is the length of the top tube. While it is less representative of the overall size of the bike than the seat tube length, it still has an effect on the overall comfort level.

The length of the top tube dictates how much of a standover gap you have, as well as how much clearance you have. It also has a huge effect on the overall ergonomics of the bike – the positioning and size of the pedals, as well as the width of the handlebars, both depend on the top tube.

Mountain Bike with Decorative Top Tube

Thankfully, you usually don’t have to worry too much about the top tube – most mountain bike top tubes slope down, giving you a much more forgiving standover clearance, as well as a much more adjustable seat length.


The Actual Numbers

With all of that in mind, let’s move on to something more concrete. In the next part, we’ll cover the actual methods that you should use to find out what mountain bike size is right for you. We’ll also include a handy chart that you can use as a convenient shortcut – but there are also several important notes that you should keep in mind.

Measuring Yourself

Knowing your exact measurements is essential if you want to pick a properly sized bike. And we’re not just talking about height – it is one of the factors, but you need to have a couple more measurements on hand to be absolutely certain.

For height, measure yourself against a wall and from the ground up. For your leg inseam, measure the distance from your crotch to your foot. Knowing your leg in-seam can let you know if the seat height can be adjusted to fit you.

Arm length and torso length factor into the equation – but only if the manufacturer uses these measurements, or if you often have issues with reaching the handlebar.

The Charts

Before we give you our “silver bullet”, there are a couple of things to keep in mind. First, the sizing charts are different for men and women – we’ll include both. Women’s bikes feature a slightly different geometry – but the changes are proportional and generally well-suited to women, so it isn’t something that you should concern yourself with too much.

Second, seeing as how bikes are differently measured depending on the manufacturer, approach each bike on a case by case basis.

Check the manufacturer’s website or product page for the concrete measurements, read the reviews, and take everything with a grain of salt – bike sizes aren’t completely accurate or set in stone – we’ll elaborate on this in the last part of the article. With all of that in mind, here are the charts.

For Men:

rider height vs suggested mtb frame size for men

For Women:

rider height vs suggested mtb frame size for women


How to Check if You’ve Picked the Correct Size

Mount the bike, then stand over it as far back as you can while still holding the handlebars. If there’s about an inch of room between the top tube and your crotch, then congratulations – the bike is almost certainly a good size for you.

Take the bike out for a spin – if you can maintain proper posture and have no issues with holding the handlebars, all is well.  If something feels slightly out of place, don’t worry – tuning and adjusting a couple of components might be able to fix the issue.


Important Notes

Mountain bike sizing is far from an accurate science – the actual feel of the bike depends on too many factors. If you’re purchasing a bike in person, ask if you can take the bike out for a test run. If your bike doesn’t feel right – don’t panic! You might be able to get a refund or a replacement – but you shouldn’t take any chances.

Mountain Bike Saddle Adjustment

But before you consider that option, try to tune a few bike components – the handlebar can be adjusted, and so can the seat height. On top of that, installing a slightly longer seat can make it easier to reach the handlebars, if that proves to be an issue.

No amount of adjustment can compensate for a serious size mismatch – but if you’re within an inch of the upper or lower limit of a particular size, tuning your bike can make up for the difference.

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What Size Mountain Bike Do I Need? — Bike Hacks