Mountain Bike Wheels Guide

Mountain Bike Wheels Guide

Mountain bike wheels are made up of three major components, the rim, hub and spokes. All of these play a vital role in the quality of the wheel and its intended use.

Rims:

• Mountain Bike rims again come in two main materials, these being both carbon and aluminium. The biggest factor in this debate is weight. 

  • Carbon will always be lighter than aluminium and some riders highly value this to help achieve the lightest bike possible. Carbon is also more laterally stiff and prevents wheel flex, and they will stay true for longer. 
  • Aluminium rims are a lot cheaper than carbon and some models today achieve the same rigidity and can be seen as even more durable.

  The width of a rim heavily impacts the wheels strength and overall stiffness. A wider rim will increase both of these attributes and we will see wheels designed for more aggressive riding with wider rims, such as a trail bike rim will often be 30mm wide and a downhill rim will be 35mm wide.

Number of spokes:

Spokes connect the rim to the hub, and affect both weight and strength.

• MTB wheels usually have 24-32 spokes.
• Front wheels often have fewer spokes because they don’t handle drivetrain torque.
• Rear wheels tend to have more spokes to cope with pedalling forces and impacts.

Hubs:

This is the part at the centre of the wheel, it houses the bearings and the componentry for the freehub. We see hubs come in many shapes and sizes. The standard now is Boost sizing, frames and forks will be designed to specifically fit these hubs and you will need to ensure you purchase the correct sized hub if upgrading your wheels.

The freehub is the part of the hub that allows the wheel to spin freely, independently of the drivetrain.

• HG (Hyperglide) - The most common, fits a wide range of cassettes
• Microspline - Required for Shimano 12-speed cassettes.
• XD Driver - Required for Sram 12-speed cassettes with a 10T smallest cog.

The cassette mounts to the freehub and this part is what creates the “clicking” noise from the wheel.