How to Choose the Right Size Mountain Bike

"What size mountain bike should I buy?"

The good news: choosing the right size can be a lot easier than it might seem. In many cases, it ultimately comes down to a matter of personal preference, and two different riders with the exact same measurements, looking at the exact same bike model, might make two different choices.

So while the choice itself might be difficult, as choosing often is, the process itself is pretty straightforward: 

1. Start with the manufacturer's size chart
2. If possible, get out and ride the bike in different sizes
3. If you're between sizes, think about how you want the bike to ride (more details below) and maybe look at the reach, wheelbase and other geometry numbers
4. Ask people who ride and sell bikes every day for their thoughts on that particular model and your own mountain biking style.
5. If you already own a mountain bike, look up its geometry numbers and compare versus the sizes you're considering

That's exactly how we do it.

Start With the Manufacturer's Size Chart

The manufacturer's sizing chart should be where you start. Make sure you look up the size chart for the exact model and model year that you're considering, as sizes may vary between models for the same manufacturer, and even between model years for the same bike.

If your height is smack in the middle of the size range for a particular size, that's probably the size you should go with. However, even then you can choose up or down in some cases and we'll explain more about that further.

Examples of how height maps to size across brands

Compare the size ranges on these mountain bikes And you will immediately see that there's quite a lot of difference. A small model is not a small on another which is why you should take the time to look up the right size chart.

See our bike guide library for model-specific details.

Notice that a 5'7" can ride anything from an S to an L depending on model and their choice of size in the overlapping ranges.

Things get a little more interesting when you're right between two sizes.

Get out and ride the bike if you can

Nothing beats riding a bike to find out not only if it's the right size, but most importantly if you really, truly like it.

You can read every geometry chart on the internet and still learn more in ten minutes on the trail than you will in three hours of forum posts.

There aren't many places in the US besides bike parks where you can rent a bike and ride it on actual trails. Bike park offerings can be limited as they're focused on downhill riding so you may have a harder time testing a cross country bike or trail bike. That's why we started up a mountain bike demo center with our own multi-brand fleet of demo bikes. We have customers both from the local area and around the US to demo mountain bikes in our year-round sunny climate.

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Think about how you want the bike to ride

If you're between two sizes, there's a good chance both bikes will fit you. They'll just ride differently. And even if the size chart shows that only one size will fit you, some people do choose to size up or down if they know exactly what they want.

Some bike models, in our experience, also size slightly small or large, and in those cases we may recommend a different size than what the chart shows.

After checking the size chart is where your own personal preferences come into play. You need to think about what you want out of your new bike. If you're buying your first bike, it might be hard to know exactly what you want. You can feel free to reach out to us for advice.

Go Smaller If You Want a More Playful Bike

Choosing the smaller frame generally gives you:

• A shorter wheelbase
• Quicker handling
• A bike that's easier to throw around
• Easier manuals and front wheel lifts
• A more playful feel on tighter trails

A lot of riders describe this as a bike that's more "flickable."

Go Larger If You Want More Stability at Speed

The larger frame usually gives you:

• A longer wheelbase
• More stability at speed
• A roomier riding position
• More confidence on steep descents
• A bike that feels planted in rough terrain

Neither choice is wrong. It comes down to personal preference.

Ask People Who Ride and Sell Bikes Every Day

Here's a look into how we help customers find the right size bike if they aren't able to visit our stores for a demo ride. We always start with the manufacturer's sizing chart. Then we start talking about preferences and look at what we know about that model.

Quote from our store owner on how he chooses his own bikes:

"I go off the manufacturer's chart. If I'm between sizes, I usually go with the smaller size. But other people make the complete opposite decision."

And on Yeti bikes specifically:

"I bought a Yeti in 2019 that was just way too big for me. At the time, Yeti had changed their sizing dramatically and started making their bikes a lot longer. I just could not get myself to like the bike in that size, so I started sizing down on Yetis. According to their size chart I should be on an XL, but I like the smaller bike and I ride L's."

Does that mean everyone should size down?

Not even close.

"We have guys who according to the size chart definitely shouldn't be on a longer bike, but they say they like the longer bike so they ride XLs."

That's why we don't just ask how tall you are.

We want to know where you ride, what bike you're coming from, what you like about it, and what you wish it did better. Those answers matter just as much as your height.

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Maybe Check the Geometry Numbers

Most riders don't need to worry about geometry numbers but some riders can read them like a book. Comparing the numbers to your current bike, or bikes that you know you like or dislike can help you make a decision about sizing. You can find geometry charts with t the exact numbers for many models in our bike model guides.

We've got people in the shop who can look at a geometry chart and have a pretty good idea whether a bike will work before they ever see or touch it. Reach, stack, wheelbase, chainstay length, head angle. Those numbers tell a story if you know how to read them.

Read our guide to mountain bike geometry.

If you're newer to mountain biking, don't stress about it. We'll help you make sense of the numbers that actually matter.

You Can Fine Tune the Fit Later

Picking the right frame size is the big decision. After that, there's a lot we can adjust to dial in the fit.

• Stem length and handlebar sweep can be used to adjust your reach
• Stem spacers and handlebar rise change your stack and riding position
• Handlebar width can make the bike feel more comfortable and more controlled
• Saddle position fine tunes your pedaling position
• Changing the crank length can help you find a better peddling position on the bike or avoid ground strikes

These adjustments make a good fitting bike feel even better. They won't fix a frame that's 2 sizes too big or too small, though.

Still Not Sure? Ask Us.

We size riders every day.

We've helped riders who were convinced they needed an XL leave happy on a Large. We've also had riders do exactly the opposite.

There isn't always one perfect answer, and that's okay.

Tell us your height, inseam, riding style, and the bike you're looking at. We'll walk you through the options and explain why we'd recommend one size over another.

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Frequently Asked Questions

Should I always follow the manufacturer's size chart?

Usually. It's the best place to start. If you're clearly within one size range, that's almost always the right choice.

Is it better to size up or size down?

Neither is universally better. A smaller bike tends to feel quicker and more playful. A larger bike usually feels more stable and planted.

Can different parts make a bike fit better?

Yes. Stem length, handlebars, spacers, and saddle position all help fine tune the fit. They work best when you've already chosen the correct frame size.

Do all Large mountain bikes fit the same?

No. Not even close. Every manufacturer has its own geometry philosophy, and even different models from the same brand can fit differently. Always start with the sizing chart for the specific bike you're considering.