After a bit of (poor) research I managed to convince myself that Shimano M8000 hubs are 11 speed compatible and rebuilt my spare CX bike wheel using one. I’ve just got round to buying an Ultegra 11-32 11spd cassette only to find it doesn’t fit after all. The Shimano CX75 hub is 28 hole only RS505 appears to be 36 hole only.
I don’t want to spend/waste much more on it what are the chances of getting a RS505 and swapping the internals over (I don’t really want to rebuild the wheel again).

Edit: I think the M8010 hubs are 11 speed compatible.

Stupid 😀

Is there a prize for being the first?

Dont shimano do decent tech documents with parts numbers?

That should at least be a decent starting point as to whether it is possible
I suspect it work out cheaper to just get the other hub and swap over – however you might as well rebuild as do that as its probably as easy.

Xt m8000 is an 11 speed group set so those hubs are 11 speed compatible!

Fraid not, I’ve been called stupid many times before. 😉

Xt m8000 is an 11 speed group set so those hubs are 11 speed compatible!

Definitely not 11 speed Ultegra compatible. 🙁

So are you saying the ultegra cassette won’t slide on to the free hub body? Or is is the cassette longer so doesn’t go all the way on?

Xt m8000 is an 11 speed group set so those hubs are 11 speed compatible!

They are NOT compatible. Whilst Shimano Road and MTB 11 speed cassettes have the same sprocket to sprocket spacing, the spline width on the hub is wider on road. MTB 11 speed is the same spline width as MTB 10 speed, and the largest sprocket of the 11 speed is offset towards the spokes.

I don’t want to spend/waste much more on it what are the chances of getting a RS505 and swapping the internals over

It’s not just the guts/freehub that is different – 11 speed road hub shells are narrower than their 10 speed road and 10/11 speed mtg hub colleagues. The spoke flange on the drive side is slightly closer to the centre of the hub to accommodate the wider freewheel body.

If that is true can you not just fit a MTB cassette – might be hard to get the right range – I am sure no one will mock you for your massive bales out gear at the back :ink:

So are you saying the ultegra cassette won’t slide on to the free hub body? Or is is the cassette longer so doesn’t go all the way on?

The freehub body is too short, the 11 tooth sprocket doesn’t engage the splines.