Kids Mountain Bikes vs BMX Bikes

Choosing between a mountain bike and a BMX for your child can be a tough one. Our guide explains the difference between the two types of bike, and a few tips on choosing the right one depending on what kind of speed demon you've got in your family.

Although they share a lot of similarities, kids' mountain bikes and BMX bikes are actually quite different.

BMX bikes are designed for riders who are into tricks, jumps, stunts, urban riding or just showing off at the skate park. They feature a standard frame size size no matter the size of the rider (unless you opt for a BMX for younger children) slick tyres and a one-speed gear system for building up speed over short distances.

For more information on BMX bikes, check out our BMX buyers guide.

Mountain bikes are designed for riding on tougher terrain or on trails. They feature larger wheels and frames, as well as multi-speed gears and potentially even suspension to absorb bumps from rocks and tree roots. They aren't as suitable for tricks at the skate park, but are equally as exciting on downhill tracks and trails.

For more information on mountain bikes, check out our mountain bike buyers guide.

The key differences between BMX bikes and kids' mountain bikes


Slick BMX tyres look a lot different to the knobbly, deeply grooved tyres you'll see on mountain bikes. Although grip is still important, a different type of grip is needed on tarmac, wood, concrete and other smooth surfaces you'll find in skate parks, so BMX bikes don't require the additional tyre features that allow mountain bikes to grip on muddy paths, loose gravel and slippery grass.


Many mountain bikes feature heavy-duty disc brakes for powerful stopping on sharp descents. These disc brakes feature a cable system from the brake handle on the handlebars to the brakes themselves that clips in place on the bike frame. On BMX bikes, you're more likely to find a V-brake (a brake featuring 2 blocks that squeeze on the tyre, with friction providing the stopping power). This keeps overall bike weight lower.

One of the biggest differences between some BMX bikes and certain mountain bikes however is a gyro braking system. Using a clever locking mechanism on the bikes handlebar post, the handlebars on some BMX bikes can be spun in any direction without the brake cable becoming twisted or preventing the handlebars from moving altogether. This is important because certain tricks require riders to spin the handlebars around, so a brake cable that doesn't get in the way is important for kids who'll be showing off at the skatepark.


The clue may be in the name, but mountain bikes are indeed designed for going up and down hills. Getting up tough inclines is made an awful lot easier with a decent gear set, with a wide selection of gears helping mountain bike riders to maintain momentum from the flat to uphill or downhill sections of the their ride. This means mountain bikes usually have a central cog and rear wheel cog, with the chain being moved onto different levels on the cog to make the bike easier to ride on different inclines.

BMX bikes on the other hand are designed for quick sprints between jumps or on freestyle ⁄ dirt courses. This means a single-gear system is much more common, so you won't get a wide range of gears to make hill climbing easier. If whoever is riding is picturing long countryside rides or downhill slaloms, then a mountain bike may be a better choice than a BMX that is designed for tricks and stunts either on the flat or at the skate park.

Hopefully it should now be clear just how different the two types of bike are, and that each type is suited to certain kinds of ride. Remember that if you still can't decide which bike to go for or your child would like to give each type a try, you can pop into your local Halfords store for help of check our guide which is full of tips on the type of MTB to choose. One of our bike experts will happily talk you through each bike and even set up a short test ride, as well as giving recommendations for whoever is going to be riding the bike. For bikes over £250, one of our expert technicians will even build your bike for free. For those less than £250, we can build the bike and complete a full safety check for only £10.