Zwift hub and alignment of cassette/micro adjustment

Hello Everyone,

I apologize in advance for what may seem like a beginner’s question.

I recently purchased the Zwift Hub, which comes with the pre-installed 12-speed cassette. I’m encountering an issue when mounting my road bike onto the Hub.

Despite attempting to make micro-adjustments to the rear derailleur, I’ve been unable to achieve smooth shifting or a quiet drive chain. This issue persists whether I adjust to the extreme “minus” or “plus” ends of the micro-adjustment scale and is particularly problematic when shifting to the extreme gears—i.e., the very large or very small cogs. I have Ultegra Di2, for reference.

For context, my road bike originally features a Shimano Ultegra 11-32 rear cassette, while the Zwift Hub is equipped with their standard 12-speed cassette.

My question is: What steps can I take to improve shifting performance on the Zwift Hub? While I’m willing to make slight micro-adjustments when switching between the rear wheel and the Hub, it doesn’t seem reasonable for the Hub to produce so much noise and offer such imprecise shifting.

Thank you for your assistance.

You might try putting the cassette from your rear wheel on the trainer to see if it works better. If it does, buy a Shimano cassette for the trainer (eg, 105). If it doesn’t, I’d take it to a bike shop for help with the adjustment.

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This worked for me.
Same Ultegra/Sunrace (Zwift) 12 speed alignment issues.
Putting the Ultegra cassette on the Hub made a big difference (still needed some Di2 adjustment).
The offset of the Sunrace cassette is well out from a Shimano cassette, as you can tell if you look at how much of the drive side adapter is sticking out from the supplied Hub cassette, against the end of your wheel hub.