Ask MBA: How to Run a Non-Boost Wheel on a Boost Fork

Q: I just bought a new fork for my older bike, but my front wheel has non-boost spacing. Is there a way to adapt my non-boost wheel to the fork without having to buy a whole new wheel?
Calvin Brewer
White River Junction, Vermont

A: One of our wrecking crew members has dealt with the same issue recently, so you aren’t alone. Luckily, there is an easy and cost-effective solution that lets your non-Boost front wheel work with a Boost-spaced fork without having to shell out for a new wheel.

The main issue is that the non-Boost hub won’t be wide enough for the fork’s dropouts, and the rotor and caliper won’t align properly. To solve this problem without having to buy a new wheel, you can use a simple spacer kit. These kits consist of two hub spacers, a rotor spacer, and longer rotor bolts to accommodate the increased spacing between the wheel and rotor. They’re available from brands like MRP, Spank Industries, and Problem Solvers, typically costing less than $50 and are simple to use.

Hub spacers will increase your hub’s width to 110mm to let it fit properly in the fork’s wider dropouts, while the rotor spacer will shift the rotor outward by 5mm to correctly align with the caliper. Fitting the axle spacers every time you mount the wheel can be a hassle, but it’s better than buying a new hub or wheel.

For front wheels, if you’re using hub spacers that use two 5mm spacers to accommodate the increased width, you won’t need to re-dish your wheel since it will still be centered within the fork. However, for kits that use a single 10mm spacer on the non-drive side of the hub, like Wolf Tooth’s Boostinator, re-dishing the wheel is necessary since the wheel is offset in the fork and is no longer centered. Additionally, if you ever use a Boost or Super Boost adapter kit on a rear wheel, you will also need to re-dish the rim since these kits use a brake-rotor spacer and a single non-drive-side spacer to keep the cassette in the same position.