Hi, I have the Jetblack FreeHub Volt xdr and the 12v Sram force cassette doesn’t work well. On the bike everything works fine, but on the zwifthub it’s a complete mess. Next week I’m going to take the bike and the trainer to the shop to see if we can get it to work the same on the bike and on the ZwiftHub. If someone has managed to make it work well in both, it would be interesting to explain the process. all the best.
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Usually making sure the cassette spacing is the same between road bike and hub, making sure everything is tighten down properly, resolves most skipping and noises. Ideally the same cassette on both too. That’s the easiest way to do it else you can figure out the two index adjustments for the derailleur as you switch between the bike and hub.
Hi @Juan_Martos
Please let me know what bike shop will tell you.
I have exactly the same issue. Zwift sent me xdr hub and I added Sram rival 12 speed cassette, but sound is not normal.
Hi, I was considering on buying the Zwift hub, until i found this forum, I also have an SRAM Rival 12spd equipped bike… so it wont work from what’ve been reading… right?
Ask Zwift if they’re offering an XDR freehub body. If not I would shop for a different trainer
Hi, after going to the bike shop, talking to Zwift customer service (they didn’t give me any solution) and doing some research at home, this is the solution for a Scott Addict with syncross wheels and a sram force 12 AXS groupset: - The 12v cassette that comes with the Zwift Hub does not work well. - if you mount the freeHub Jetblack Volt XDR on Zwift Hub. The problem is not solved, the sram force 12v cassette does not work well. PROBLEM: In both cases, when you mount the bike on the zwift hub, the gap between the cassette and the frame is almost 2 millimeters less than when the wheel is mounted. SOLUTION: I have created a washer made of engine gasket material (in Spanish “carton-piedra”) like the one in the attached image. I put this washer on the axle between the cassette and the frame. With this the zwift hub works perfectly both with the 12v cassette that comes from the factory, as well as with the FreeHub Jetblack Volt XDR and the sram force 12v cassette.
With this new part I can enjoy my ZwiftHub 100% on my Scott addict RC with sram force 12v AXS
The next step that I am carrying out is to create new these two pieces:
1°A new shorter adapter.
2°A new longer core plug so you don’t have to use the washer anymore.
Juan, you’ve made some interesting discoveries. I think there some problems with tolerances when using the Zwift Hub and SRAM AXS groupsets. Please keep us informed if you make any further progress.
Personally, I’ve deal with the differences between my wheel and the Hub using the micro adjustment in the SRAM AXS app to re-index the rear derailleur. If I want to ride outside, I set the app to ‘5’. If I’m using the Hub, it gets set to ‘12’.
In case you want to have a ‘better’ solution, seems they now do have the XDR Freehub body. Can’t post the link but just google ‘ZWIFT HUB XD/XDR FREEHUB BODY’ and it’ll bring you to the Zwift website
I received my first trainer (the Hub) last week and ran my SRAM 12spd on the factory installed SunRace 12spd cassette. I ran my bike thru Watopia for a few days while I waited for my XDR freehub and cassette ($250). While shifting was rough especially around 250> watts, it was pretty quiet. Imagine my surprise when installed the new cassette how incredibly loud and grinding it was! The shifting was great but the chain was too cross-chained -it’s not a matter of micro-adjusting or derailleur hangar alignment. The guy above with Scott Addict has it figured out… on one side the adapter needs to be shorter and the cassette side should fit a spacer and should be longer to fit said spacer. Or manufacture a hub that pushes the cassette out another mm or two. Meanwhile it’s second nature to back-off the power for a split second to make the SunRace cassette work - I don’t even think about it. Not ideal for racing or steep hills but it’s workable and quiet. Anyway, I wouldn’t consider the Hub SRAM compatible. I’m using a rim brake bike (narrow dropouts) so maybe bikes with different size dropouts work better or differently but I see a lot of issues on the 'net with this. Take the $250 you’re gonna have to drop on the cassette and hub and get a different trainer
So I’ve followed this thread with great interest, as I’m trying to work out how to mount my Cervelo Caledonia onto the smart hub for the winter.
I emailed them about compatibility and this was the reply:
I am happy to let you know that your setup will work with the Zwift Hub, however, allow me to share additional information about the Sram flat-top chain. In testing, Zwift Hub with SRAM 12 speed flat top group sets, we found gear shifting and drivetrain noise met our expectations. Though we have tested shifting quality, we have not tested wear and tear. If you are concerned, our recommendation is to upgrade to a JetBlack Volt XDR FreeHub and SRAM XDR cassette.
Regarding your question about the free hub, once you place your order for the Zwif Hub you can contact us back and we will be able to send you the free hub body. Last but not least, if necessary we would be able to refund up to $50 dollars or the equivalent in your local currency after you provide a copy of the receipt of the cassette.
So I might take that and see what happens. But if a simple washer for spacing works, that’s also a good piece of info.
If you have a mechanic you trust to work on your bike, I’d ask that person what they think of using the bike with a Shimano-compatible cassette. I suspect most would advise getting the XDR freehub and a SRAM cassette for best shifting performance and compatibility with your chain, if you can afford it.
maybe they’ve made some manufacturing changes to the XDR freehub to correct the problems. You can have mine for free haha. once you install the everything, and if there are still problems, you’ll easily be able to see the cross-chaining issue clearly. I think it’s very possible a decent mechanic could look at that and help you space out the cassette properly. there’s not a whole lot of room to work with, but maybe. i’m still back to the their original SunRace cassette with my SRAM-12spd. It definitely wears the chain faster going back and forth between the cassettes. shifting is horrible under high power/racing/climbing situations
Reckon a standard 2mm washer from the hardware store would do the trick, as the Scott rider said above?
Also, when you said wears the chain faster, how fast are we talking? Like after 100km there’s noticeable wear? Or over a longer time? I’m probably going to ride about 150km/week through the winter and not much more tbh… I’m also doing a lot of running
I think it’s quite possible that some sort of spacer could fix all scenarios. There are like 4 different dropout sizes between rim & disc brakes so I don’t want to be too hopeful. I should ask my mechanic actually. I’ve only been indoor training for a season and i’ve decided that 2500 miles is probably a good point to swap out the chain due to wear from both cassettes. plenty of people swap out there chains at that point anyway for other reasons although the average recreational rider could easily get 5k out of one. I will say the SunRace cassette that comes with the Hub is much quieter on my SRAM 12spd chain than the most tuned SRAM 12spd i’ve ever heard. it’s just annoying when you lay down a ton of power and a bunch of grinding mid-shift occurs. if you’re not into racing, KOMs or sprints on Zwift, the original cassette it comes with might work just fine
the fix is in! check out the article in Cycling News
Zwift Hub One launches with a universal singlespeed cassette and smartbike…
Zwift solves long standing compatibility problems and makes it easier than ever to ride indoors
Without any price increase you can now use the Zwift Hub smart trainer to shift virtually and new hardware offers a choice of a universal singlespeed freehub that works with almost any bike, no matter your groupset.
Hello, I have a 12 speed 10x30 Sram AXS, I asked for the compability with the cog.
Here’s the reply :
First of all, I must inform you that your bike is not compatible with the standard Zwift configuration. For this reason, your bike is not compatible with Zwift Cog, which is not compatible with the XD/XDR system. To make your configuration compatible, I recommend that you also order an XDR freewheel body. Then install an XDR freewheel body and a cassette with the same ratio.
Conflicting info on this. (I have no experience with the Cog. If using a 12 speed cassette I would go SRAM & XDR)
That’s incredible that even in intern they don’t seem to have the same discourse 
Based on a number of posts like yours I get the impression Zwift support doesn’t really know anything about bikes and how they work. If you have the standard Shimano compatible freehub body on your trainer already (or buy one if you have an XDR body on it) I don’t see why you can’t just run the Zwift Cog, as they said in the link Paul provided it is compatible.