27.5 vs 29 mountain bike - how to choose the wheel size that suits you best

When mountain bikes were invented, they were rigid with 26 inch wheels. Modern mountain bike geometry paved the way for bigger wheels that rolled over rocks and roots much more easily.

Monster trucks have huge wheels for rolling over huge obstacles. It's the same idea with mountain biking albeit on a much smaller scale.

MTBs with 29 inch wheels are often referred to as 29er mountain bikes. In short: they're famed for their increased stability and smoother riding quality. 29 inch wheels also have a larger contact patch with the ground. This means better traction whether you're hitting the berms, grinding up a steep climb or braking at the end of your run.

• Greater rollover
  Riding over rough terrain is effortless with bigger wheels
  
• Less probability of pedal strike
  29 inch wheels require bigger tyres than their smaller counterparts. The extra millimetres added to the standover height of the bike can prevent pedal strike when you're climbing on rocky, loose trails.
  
• Increased stability and traction
  Bigger wheels have a greater contact patch with the terrain
  
• Easy to maintain speed
  Once you're up to speed, it's much easier to stay there due to the forces on a wheel with bigger diameter.
  

• Sometimes heavier
  Bigger wheels means a bigger rim and longer spokes which all adds up. That said, there are some very impressive lightweight 29 inch wheels out there.
  
• Slower acceleration
  Big wheels take more energy to accelerate compared to smaller wheels.
  

29 inch wheels are popular with:

• cross-country riders
  
• trail riders
  
• and enduro mountain bikers



They're also great for taller riders.

If you're looking for a mountain bike for everyday trail riding or downhill racing with excellent stability, traction and control, 29 inch wheels are the perfect size.

Beginners will feel more confident with larger wheels, and intermediate riders will be able to push themselves in terms of speed and technique.

After a few years of playing around on big mountain bike wheels, the bike industry recognised a need for wheels with a little more playfulness. Rider who wanted to get air and flick the bike around a bit more required something lighter and more nimble.

Introducing the 27.5 inch mountain bike wheel.

When they first launched around 2014, they seemed like the perfect middle ground between small 26 inch wheels and big 29 inch wheels. MTBs with 27.5 inch wheels became popular and are still the choice of many. Here’s why:

• Quicker acceleration
  Smaller wheels have stronger, stiffer rims owing to the smaller diameter, giving greater power transfer and quicker acceleration.
  
• Great for smaller riders
  Smaller wheels fit into smaller frames eliminating the toe overlap problem.
  
• More agile and playful
  A smaller wheel size means you're able to throw the big around and get some big air.
  

• Less stable at high speeds
  Riding fast, technical descents may be more difficult if you're inexperienced.
  
• Slower speed
  Though they're quick to accelerate, 27.5 inch wheels are slower than 29 inch wheels: so to keep the same speed as a 29er, you'll have to pedal harder.
  
• Harder to ride on rough terrain
  The attack angle on smaller wheels is steeper, and therefore loose, rocky trails are particularly hard going.
  

If you want a bike that's a little rowdy, poppy and playful, 27.5 inch wheels are for you. They make the bike easier to throw around and will help you hone your skills.

Smaller wheeled bikes are perfect for smaller riders thanks to a smaller turning circle and often a lighter bike overall.

Trail, freeride and even some enduro bikes are often specced with 27.5 inch wheels. Speed and air are the name of the game. With quick acceleration, these bikes can go just about anywhere.

Like its namesake hairstyle, it's business at the front and party at the back for this setup.

A mullet bike is a mountain bike with a 29 inch wheel at the front and a 27.5 inch wheel at the back. You benefit from the stability of the bigger wheel at the front and its ability to roll over roots and rocks. And the smaller 27.5 inch rear wheel brings the nimble and playful party attributes.

Although it’s a relative newcomer to the MTB world, the mullet bike is catching on. If you think you need a little bit of both, our deep dive into mullet bike setups is useful.

The decision really depends on your preferred riding style and your experience.

As a general rule of thumb, you will benefit from 29 inch wheels if you're a tall rider and enjoy bashing around your local trails.

Shorter riders generally have a better experience on 27.5 inch wheels.

Height is just one of the factors, though: if you want to hit the bike park and get big air on some jumps, 27.5 inch wheels are a great choice. If you're into more cross-country style riding or some sweet flowy singletrack, larger wheels are perfect.