Compatibility

I have 12 speed MTB and Zwift is sold out of the Zwift Hub 12 speed. If I buy an 11 speed hub, will a 12 speed cassette fit onto it?

Thank you,

Whose gears do you have on your MTB? Is it SRAM?

Yes, it’s SRAM.

SRAM mtb’s use XD freehubs (and no, a SRAM 12sp cassette it wont mount to a Shimano 11-sp freehub) but one exception applies …SRAM sell a low-end NX PG-1230 that uses Shimano freehub.

If you don’t know what you have, the bike specs should tell you (post them up here if you are not sure) but you can also tell by counting the # of teeth on smallest cog - NX has 11 whereas all other SRAM Eagle 12-sp cassettes have 10t.

There was a recent discussion of using a mountain bike with a 1x drivetrain with a 32t chainring with the Hub, and the conclusion was that the high gear is too low. Using a PG-1230 will make the high gear lower since 11t is the smallest cog that can fit on a Hyperglide freehub body. If your bike can support a larger chainring, you could use the PG-1230 with a larger chainring and a longer chain. Exactly how big the chainring needs to be depends on your power, whether you expect to sprint in Zwift, etc.

Better options would be to get a road bike, or a trainer that has an available XD/XDR freehub body such as a Kickr Core.

I found my MTB unusable with the 32 crank/12 cog combo. Even in 32/10 it would spin out on the hub like i would with 32/50 on a real road. I ended up swapping to a gravel bike with a 48 up front. Its much much better but I think having a 50 or 52 would be even better up front.

My bike has a SRAM NX Eagle, 12 speed 11-50T cassette. My concern is if the axle on the 11 speed Zwift Hub is long enough to accommodate a 12 speed cassette.

Yes the SRAM PG-1230 cassette is designed to fit on a Hyperglide 11 speed freehub body.

I had a bike shimano 10 speed on my zwift hub. Now I have a new bike with 12 speeds, do you think a 12 speed cassette can be placed on the same body because now I placed it and it makes a lot of weird sounds when biking and sometimes the speed change without I am asking for it?

The freehub on the Zwift Hub supports Shimano 12 speed road cassettes. If you install one of those, you need to remove the 1.8mm spacer behind the 10 speed cassette.

Thank you for your message! But is it possible to install it with the 1.8mm spacer still on? Because when I removed my 10-speed cassette, I didn’t see any spacer. Do you know why my cassette makes a weird noise when I pedal and why my chain skips, even though the cassette size is the same as the one I use on my bike?

10 speed and 12 speed cassettes are not interchangeable. They have different spacing so you must use the cassette designed for your drivetrain.

I’m not sure why you did not have a spacer under the 10 speed cassette. That is a requirement for 8-10 speed cassettes.

You may also need to adjust the derailleur when you put the bike on the trainer.

If you can’t figure it out, I recommend taking the bike (including your rear wheel) and the trainer to a bike mechanic.