Is anyone aware of a list of freehub interfaces (freehub to hub body) anywhere? I assume that Shimano Hyperglide would have been the most common MTB one for a long time, though I can’t find an interface drawing for it, but in road world there seems to be several, and then when I check back to MTB land there actually seems to be a fair few there too. I’d like to make a thing that has broad compatibility with bike freehubs but it looks like there’s no such thing as a standard.

the freehub to hub interface is most likely entirely unique to every brand and model of hub, ie a dt swiss ratchet freehub is never going to work on/in a a 3 pawl hub

Maybe something on the Sheldon Brown site.
Far as im aware theres microshift, Shimano uniglide,Shimano HyperGlidee, campag, sram XD and possibly a couple of older discontinued ones.

There is almost no intercompatability between freehubs and different makes of hub – apart from OEM hubs made by the likes of JoyTec/Formula, Novatec etc that are sold under different brands, almost every freehub/hub interface is proprietary to the manufacturer.

Do you actually mean freehub interfaces (i.e. FH body to the hub shell) OP or Cassette interfaces (i.e. Cassette to FH body)? I’m assuming you meant cassette interfaces.

Not exhaustive but here’s a basic list of most of the Cassette/FH body interfaces you are likely to encounter on Road and MTB bikes.

Do you actually mean freehub interfaces (i.e. FH body to the hub shell) OP or Cassette interfaces (i.e. Cassette to FH body)? I’m assuming you meant cassette interfaces.

No, I mean the interface to the hub, not the cassette. The cassette interface is surprisingly limited in variation, I noted.

I think the replies so far have pretty much matched my googling, they’re all bloody different. I thought HG might be the best “general” interface to replicate:

but then I notice:

I still think I’ll take the HG route.

There are a million freehub interfaces for HG freehubs.

HG is just the interface for the cassette to the freehub body.

Every hub has a proprietary way that the freehub engages the hub. Could be either pawls or ratchets.

I don’t know what you’re designing but it might be best to pick a few popular hub interfaces and get it to work with those. E.g

Dt swiss ratchet
Hope Pro4 pawls
Novatec pawls
Shimano

I’m not sure if Novatec hubs use all the same internals or not but they make a huge number of hubs both in their brand and for other brands who white label the hubs.

I think there is some variability in Shimano hubs too