MTB Wheel Adaptors

What is an MTB wheel adapter used for

Axle end caps can be replaced on the hub to change the spacing or axle type, without touching the spokes or buying a new wheel. When changing frame or fork, this is by far the most affordable solution — provided you know its limitations.

What an adapter allows you to do

• Converting from 9x100 mm quick release to 15x100 or 15x110 mm Boost at the front.
• Converting from 20x110 to 15x110 mm on a front hub designed for both.
• Converting from 12x142 to 12x148 mm Boost at the rear — with an important caveat, see below.
• Changing freehub body on some hubs, where the end cap is part of the assembly.

The limitation of rear Boost

A 12x142 to 12x148 adapter widens the hub properly, but the rim remains centred on the old spacing. The wheel spins and fits, but it is no longer centred in the frame and the chainline shifts. On some hubs, complete kits correct the offset; on others, the wheel must be re-dished, meaning adjusting the spoke tension. Check this before ordering.

Check the exact hub reference

These parts are strictly proprietary, and the product ranges look very similar. A DT Swiss 350/370 does not accept the end caps of a 240, nor those of a Ratchet EXP. For Mavic, ID360 and QRM Auto are distinct. Check the hub brand, model and generation before choosing.

To find out more: How to choose your MTB hubs

See also: MTB hubs · MTB front wheel axles · MTB Freehub Body