Zwift Hub Grinding

But this is the way, I am afraid.

Is this true if I get the same cassette on my bike and trainer? I was hoping by doing that I could avoid tweaking the index everytime.

It does not have to be ta same cessette as long as the spacers are the same. You may need a wider or narrower spacer so that the indexing stay the same

I don’t think this is correct.

The spacers are for different speed cassettes to fit the hub.

you may need to index the gears due to the alignment of the cassette on the hub of the trainer compared to the hub of your wheel. Also, when you tighten the quick release skewer if you have this tighter or looser than it previously was this can slightly affect the position of the rear mech hanger so can mean you need to tweak the indexing slightly.

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I actually tried this. The spacer that’s on my wheel is 1.5mm and the one that was on the trainer is 1mm. I swapped the spacer but the grinding still occurred.

My bike has a thru-axle but I think this would still apply?

@Chris_Holton

You are 100% correct. The reason for my comment is I have one wheel where I need a different spacer than my other wheels to get my indexing perfect.

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If all wheel/freehub/cassette alignments between different setups/bikes where the same, there would be no gear adjustment necessary at all…

I am having the exact same problem. The zwift cassette almost seems to wide. Maxing out all adjustments I still could not get a correct alignment.

After trying 2 different bikes adjusting limit screws, indexing. The zwift hub excessively grinds. The grinding and vibrations make the ride unbearable. I am seeing multible threads and comments with this problem. Obviously this is a new product with problems. This problem needs to be addressed by zwift quickly. If you have the same problem please comment so zwift can see. I have already started contacting zwift.

Are you shure that the cassette on the zwift hub is the right one for your bikes gearing?
I mean something like wrongfully trying to combine a 10 speed cassette with a 11 speed gearing or similar…

I wonder how many folk are using a now-worn chain with their new Zwift cassette? I’d suggest that it’s worth trying a new chain, or switching cassettes from your bike in order to eliminate that issue (as well as learning how to adjust the indexing quickly).

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Both bikes 11-28t cassette. 11 speed cassette on the zwift hub. I wish it was a simple like that.

Bike is brand new

I ordered my hub without a cassette and ordered the same cassette that i run on my bike to ensure that there wouldn’t be any issue with chain length. I did play with tension on the quick release skewer to get the indexing pretty close and a 1/4 turn on the barrel nut adjuster for the rear derailleur and ran through the gears a few times and everything is quiet and shifts as it should. It appears the spacer provided is 1 mm while the spacer on many 10 speed bikes are 1.8 mm.

Hi folks! I experienced this problem too - new Zwift hub (8 speed) turned up, attached my bike, lots of grinding noises, not very pleasant.

Ended up taking my bike for a gear service which included replacing the chain and cassette and it’s fixed the problem completely :+1:

My chain wasn’t super old and worn, but (like others have said in this thread) the chain and cassette tend to wear down together so the problem isn’t as pronounced until you move onto a brand new cassette.

Hope this helps anyone experiencing this problem!

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Same issue here. Took my bike in to repair shop and it was running sweet on the road back on the trainer, same grinding only smallest rear cogs, or if very low cadence on the high ones. Contacted Zwift support. After many videos they agreed to replace the hub. Same issue.

Yes, I have transferred cassette from Roadwheel, same issue. Yes, I have indexed front and rear derailleurs to death, and whilst I’ve minimised the issue, it’s definitely still there.

Usable, but not what I’d expect.

Apparently this issue is not limited to Zwift, I’ve seen the same reports with respect to Kickr Core too.

FWIW, I find using ERG mode in the middle cogs offers a very smooth ride

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I got a used Zwift Hub for Christmas and my first two rides feel grindy as well. My chain is relatively new, with 0.5 wear on the Park Tool wear indicator, and the cassette on the hub is nearly a 1:1 to what’s on my bike. Unit seems in good condition overall but I don’t doubt it could use some maintenance of some sort. I see nothing online about maintaining the internals of the machine, even when searching “JetBlack Volt maintenance/repair.”

I posted in another thread. I had similar experience of rumbling/grinding in certain gears that vibrated through the bike and could be felt in the pedals.
I noticed the 9 speed cassette I was using had rivets on the largest cog that prevented the spacer sitting flush and meaning it was out by about 1mm

I used a dremel and ground down the rivets and there has been a noticeable improvement to smoothness.

You can also order spacers designed for cassettes with rivets.

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