Has anyone seen or used one? I’m assuming they just replace the end caps on the hub so swapping wheels between bikes should be relatively straightforward. But on the bike with boost forks will it require some form of spacer for the disc brake to move the caliper in 5mm?

I think they only work on the front hub – end caps space it out to 110, and then another spacer moves the disc across so it fits in the caliper. It can’t be done on the rear hub since the cassette is in a different place.

If you’re looking to swap a wheel between boost and regular forks, you’d need to move the disc every time, you can’t move the caliper across on a boost fork.

you can’t move the caliper across on a boost fork.

Someone was suggesting offset caliper mounts (since most forks are 160 or 180PM you may be using an adaptor anyway) will be available for those wanting to use an old wheel with standard disc spacing. Suppose which option you choose depends on which other wheels/forks you plan on running.

I think they only work on the front hub – end caps space it out to 110, and then another spacer moves the disc across so it fits in the caliper. It can’t be done on the rear hub since the cassette is in a different place.

Disc spacer makes sense as a starting point with longer screws to go through the spacer and into the hub. After writing it i’m not sure an offset caliper mount work given the forces the bracket would have to take?

It wouldn’t be a regular swap, it’s just I fancy being able to run the B+ wheels on my full sus from time to time and there should be plenty of clearance on that given the frame and forks. The wheels will mainly be on the hardtail.