Early on, mountain bikes came with 26˝ wheels. Then Gary Fisher came along and made 29-inch wheels that quickly became popular thanks to their momentum-preserving speed. Since then, 26˝ mountain bike wheels have been replaced by 27.5˝ wheels that deliver some of the benefits of 29ers while offering more nimble handling and a better fit for smaller riders.
27.5-inch wheels
The better small wheel. This size is faster and rolls over obstacles a lot easier than a 26˝ MTB wheel, but it’s still more nimble than a bigger 29er wheel. This wheel size is a great choice for smaller riders, downhill mountain biking and some trail riders who prefer to pop off jumps and throw the bike around on the trail.
See the bikes29-inch wheels
Why 29er mountain bikes? The bigger diameter gives 29˝ wheels the advantage of speed. They also roll over obstacles easier. But when comparing 27.5 vs 29, these bigger wheels take more effort to control. Since these are the fastest-rolling wheels, they’re the best choice for cross-country mountain bike racing. Their speed and momentum also makes them great for enduro mountain bikes and general trail riding.
See the bikesSmart Wheel Size
While 29-inch wheels are generally the fastest, they can be more difficult for smaller riders to control. That’s why Trek offers our most popular bikes with Smart Wheel Size. We pair each frame size with the wheel size that best fits that size rider. That means larger frame sizes get 29-inch wheels while the smallest sizes get more proportional 27.5-inch wheels, and everyone gets the fastest wheel that fits.
Mountain bike tyre sizing
Mountain bike tyre width recommendations usually depend on riding type, and sometimes riding conditions.
Cross country bikes
Since cross country riders are all about speed and efficiency, they want the lightest, fastest-rolling tyres, and they are often willing to sacrifice some grip and stability to save weight. So XC bikes usually have narrower tyres with smaller tread.
Shop cross country tyresTrail and enduro mountain bikes
These riders want the added grip of wider tyres with bigger tread. The trade-off is added weight.
Shop trail and enduro tyresPlus tyre mountain bikes
These trail bikes come with extra wide tyres that offer more traction and stability than standard trail tyres. Plus tyres are heavier, but they give you a lot more confidence.
Shop plus mountain bike tyresFat tyre mountain bikes
These bikes have the widest tyres that give you tank-like traction and rock-solid stability so you can steam roll over loose terrain and go where other bikes can’t. Fat tyre bikes aren't quite as quick or nimble as trail bikes, but they give you the best in all-season, all-terrain capability and grip.
Shop fat bike tyres