Kids’ Bike Sizes – What You Need To Know

young girl riding the Specialized Jett Kids bike with sunset

Maybe your child has grown out of their bike, or perhaps you have a little one who’s ready to start riding. Regardless, you need to purchase a kids’ bike. Here’s a guide to help you through the process of getting the right bike for your child.

When should I get my child on a bike?

New research has come out saying that the earlier a child gets on a bike, the more likely they will continue to bike later in life. Once your kid conquers walking, they are ready to start using a balance bike. In other words, the earlier, the better!

Balance bikes are also known as ‘run bikes’ or ‘strider bikes.’ They come in two sizes – 10 inches and 12 inches (wheel diameter) – 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.

Specialized Hotwalk Kids Run Bike in Red

What’s after a balance bike?

After the balance bike, it is time to upgrade to a bike with pedals. Picking the next size bike is going to depend on your child’s height. Below is a size chart, but it is more of an approximate guideline. The best way to determine size is to take your child to an ERIK’S store and have them sit on the different size bikes.

Kids' Bike Sizes Chart

How do I know if the bike fits my child?

Have your child sit on a bike and ask yourself these important questions:

  • Can they easily reach the handlebars?
  • Are they able to sit on the seat and touch their feet on the floor?
  • Can they reach the pedals?

If you answered ‘yes’ to these questions, then this bike is probably the correct size.

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.

bike seat post

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 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 Bike Trade-In Program. It’s perfect for those buying a bike for their fast-growing kids or anyone ready to upgrade their current bike. Learn how it works here.

Specialized 2021 Riprock Base 24 Inch Kids Bike Kids Mountain Bike

When should my child start riding geared bikes?

Geared bikes are typically found on 20″ bicycles and larger. When your child gets tall enough to ride this size, you can choose between getting a geared bike with hand brakes or sticking with one-speed and coaster brakes (where you pedal backward to stop). Base this decision on whether you think your child is ready to learn how to use gears. Do they need gears? Will they be able to handle using a handbrake instead of the coaster brake?

Finally, go riding!

Once you get your child a bike, ride as a family – even if it’s just around the block to start. You’ll be able to demonstrate how to navigate roads and intersections safely. Studies show that kids are more likely to get into cycling if their parents ride. Biking can be the perfect family adventure – outside and away from the screens! And make sure everyone wears their helmets. See our blog Does Your Child’s Helmet Fit? for more on kid helmets.

Bring your kid to ERIK’S for a test ride today!

If you want to keep learning about Kids’ bikes, check out our Kids’ Bike Buying Guide. If your kid wants to explore tricks and dirt jumping, they may prefer a BMX bike which this guide explains. Or, simply stop by your local ERIK’S and check out our huge selection of kid’s bikes. Our experts will answer any questions you have and help you find the perfect bike to keep your kiddo riding happily!