Posted by Paul Hoyle on 2nd Oct 2025
Mountain Bike Wheel Size Guide (Adult)
What sizes are available?
On original mountain bikes we only used to see bikes fitted with 26” wheels. However over the years wheels have grown stepping up to 27.5” and then more recently 29”. This was done to increase the rolling efficiency of the bike and stability at speed. In the past few years a new trend emerged of mullets (AKA MX), with the bigger wheel up front (29”) and smaller wheel at the rear (27.5”)
Is a bigger wheel better?
- The bigger 29” wheels provide riders with a lot more balance at speed as the greater gyroscopic forces keep the wheel pointing upwards, also due to this larger circumference the wheel can roll over obstacles such as rocks and roots with greater ease making the bike feel more “planted” and provides more grip due to the increase in contact surface.
- All of these benefits come with a slight trade-off in manoeuvrability. Bigger wheels feel stable and fast, but they don’t quite offer the same nimble, playful handling as 27.5”. The smaller 27.5” wheels are easier to throw around on the trail and in the air.
- Jump bikes typically use 26” wheels, allowing for agility in the air.
What size is best for me?
- 29” - Stable, confidence inspiring, great for covering rougher terrain at speed.
- 27.5” - Agile, responsive, and fun for riders who like air time.
- Mullet / MX - A common compromise is the “best of both worlds”, stability up front with the ability to move the back around more freely.
- In regards to 26” wheels we only tend to see these on small adult bikes or jump bikes as these are specifically designed to be more in proportion for smaller riders or nimble for tricks in the air.
Wheel size mainly comes down to rider preference and your riding style, we recommend trying a few different set ups to ensure you choose the correct one for yourself, or alternatively talk to our team who can walk you through our own personal experiences riding in different tracks and terrain.
