Zwift cog skipping after chain replacement

Bugs and Support
1

I’ve been using an older bike with my trainer with a zwift cog without issues for a year now (almost daily) but because I want to use this bike outside this winter I deceided to replace the chain and cassette. While my bike was away I used my new bike (only 1000km) on the same cog without a problem.

Now my old bike is back and I wanted to test it again in Zwift but now my new chain keeps skipping on the cog when applying more pressure (about 2.5 w/kg). I checked (and cleaned) the cog and the teeth look fine to me. But I just can’t get it to stop skipping. So I don’t understand what I’m doing wrong here.

2

It’s possible the Cog is worn out. Chains vary and you may not get the same results from two chains. I would contact support and see if they want to send you a new one. They’re often pretty generous about that and it costs nothing to ask.

3

Is it a correct chain?

4

Either the Cog has worn out which would take years or its the wrong size chain. Not sure what you are supposed to have but the likes of a WattBike uses a single speed chain which is about as strong as it gets because of its profile.