• BIKE SIZING GUIDE
    FOR KIDS AND ADULTS

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ADULT BIKE SIZING

The size of your bike is incredibly important as it affects comfort, safety, and pedaling efficiency. A bike that fits you well will let you enjoy your ride and get the most out of it. However, an ill-fitting bike can lead to discomfort that may ultimately make you not want to ride. Best to avoid that!

If you're looking for a road bike size chart or a mountain bike size chart, our bike sizing chart is based off your inseam and height to help you select the appropriate size. Though this bicycle size chart is a great guide and place to start, there are other factors that play into bike sizing. Continue reading to find out how to be sure the size is correct.

A handy way to measure your inseam is to stand up against a wall with a hardcover book, square up the hardcover book with the wall and your inseam, and measure from the top of the book.

HOW DO I FIND MY SPECIALIZED S-SIZE?

Some Specialized mountain bikes use S-Sizing instead of the traditional mountain bike sizing. S-Size bikes come in sizes with similar head tube lengths and standover heights, which allow you to choose the size that best matches the feel you desire for your riding style. Smaller S-Size numbers are going to be more nimble, thanks to their shorter reach and front-center measurement, while larger S-Sizes deliver more stability and a roomier ride.

For example, if you're 5'8”, you could ride a bike sized S2-S4. If you want a ride that's balanced between maneuverability and stability, S3 will be your size. If you want a more nimble ride, you'd drop down to an S2. For a bike that's more stable at high speeds, bump up to an S4.

HOW DO I KNOW IF MY BIKE IS THE RIGHT SIZE?

Standover clearance is an important safety consideration, so when you are standing over the top tube of your new bike, you should have at least one inch of clearance.

You'll want at least 1 inch between you and the top bar of the bike.

Next, you'll want to set the saddle height. Get a friend to hold your bike while you get on the bike. Place your heels on the pedals and move your foot to the bottom of the pedal stroke. With your heel on the pedal, your knee should just lock out without you having to reach for the pedal. Then, when you pedal normally, with the ball of your foot on the pedal, you should have a slight bend in your knee. When adjusting the seat post, watch out for a line on it that indicates the maximum height the seat can be raised. For safety purposes, the post should never be sticking up past that minimum insertion line. Riding a seat beyond this point is dangerous and could result in a malfunction of the bike frame. If you're having to raise the seat post past this point, you should probably be on a larger size bike.If you have your inseam measurement from above, you can take that number times .883 to get a good starting point for your saddle height.

Lastly, you should be able to easily reach the handlebars in a way that's comfortable and that allows you to control the bike. If the bike is too small, you're likely to feel cramped on the bike, and if the bike is too large, you'll feel like you're stretching to reach the bars. If you have to stretch to reach the handlebars, you won't be able to control the bike.

HOW ARE BIKES SIZED?

Different styles and brands of bikes will be sized differently.

  • Road and drop bar-style bike sizes are listed in centimeters (cm).
  • Mountain bikes are typically listed in standard sizes (S, M, L), or sometimes inches (in).
  • Most other adult bikes will come in standard sizes (S, M, L) or inches (in).
  • Kids' bike sizing is based on the wheel size. The smallest bikes usually start with a 12” wheel size (some balance bikes may have a 10” wheel). The largest kids' bikes will have 24” wheels.

ADULT BIKE CATEGORIES

KIDS' BIKE SIZING

Kids' bikes are sized differently than adult bikes. Unlike adult bikes, which are sized off of the frame, kids' bike sizing is based on the wheel size. The smallest bikes usually start with a 12” wheel size (some balance bikes may have a 10” wheel). The largest kids' bikes will have 24” wheels. After that, kids begin to move into small-sized adult bikes.

Kids' Bicycle Sizing Chart

Rider Height Bike Size
31in - 35in Balance Bike
35in - 39in 12in Bike
39in - 42in 16in Bike
42in - 50in 20in Bike
50in - 58in 24in Bike
58in + Adult Bike Sizes

Kids' bike sizes are based on the size of the wheel on the bikes. Unlike adult bike sizes—which measure the length of the seat tube to determine the size—wheel size is an easier way to list standard sizes across manufacturers, regardless of the frame geometry. However, it is important to note that just because two youth bikes might be listed as the same size, they may fit differently. If your child is in between two sizes, choose the larger size.

Balance bikes are also known as "run bikes" or "strider bikes." They come in two sizes of wheel diameter—10 inches and 12 inches—and are suggested for kids 2-5 years old. This bike has no pedals, so a child uses their feet to push the bike along. This is a great way for them to learn one of the hardest parts of riding a bike: how to balance on two wheels.

HOW DO I KNOW IF MY CHILD'S BIKE FITS?

You always want a kid's feet to comfortably reach the ground when they're sitting on the seat. For some children, comfortably will mean their tip-toes touch the ground, and for others, it may mean their feet are flat on the ground. This means that when they come to a stop, they can have complete control over the bike.

It's also important that the standover height is correct. With the child standing over the top tube of the bike and their feet flat on the ground, there should be room between the top tube and the child. If the child is resting on the top tube, you should consider the next size down.

Lastly, your child needs to be able to easily reach the handlebars in a way that allows them to control the bike. If they have to stretch to reach the handlebars, they won't be able to control the bike.

HOW DO I KNOW IF MY CHILD IS TOO BIG FOR THEIR BIKE?

As your child grows, you'll need to raise the bicycle seat. Make sure to pay attention to where the minimum insertion line is on their seat post. Their seat post should have a line that indicates how far up the seat can be raised. For safety purposes, the post should never be sticking up past that minimum insertion line. Riding a seat beyond this point is dangerous and could result in a malfunction of the bike frame.

MY CHILD IS GROWING FAST! CAN I BUY A BIKE THEY WILL GROW INTO?

Parents often ask us about buying a size up since their child is growing. We understand that you want to get as much use out of the bike as possible, but we encourage you to consider the safety issues that come with buying a bike that's too big. Especially if the child is new to biking, riding an oversized bike can be hard to balance and difficult to stop.

A better option is ERIK'S Guaranteed Trade-In Program. It's perfect for those buying a bike for their fast-growing kids (or anyone ready to upgrade their current bike). Trade in your kids' used bike and get ERIK'S store credit to use towards a new bike for them...or anything else we sell! Learn more here.

KIDS' BIKE CATEGORIES

SHOP WITH ERIK'S FOR YOUR NEXT BIKE

Erik was only 13 when he started Erik's in 1977. His first bike, a hand-me-down from an older family member, sparked his interest in bikes. With entrepreneurial spirit, and the money he saved from his job as a paperboy, Erik began his business. Erik's Bike Board Ski has grown into the Midwest’s leading bike, snowboard & downhill ski retailer. We are passionate about our sports & experts on all the gear we carry! Learn more about ERIK’S History.

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