Hi Everybody!
So I have a bike which I use to ride with Zwift cog 1 during the winter months. Last week went on and serviced the bike: I changed my bottom bracket my chain and my brake pads.
I returned home with the bike riding it and I did not experience any issues. Everything was smooth.
Then at home I took the cog from zwift and cleaned it so it’s spotless for the new chain.
When I put everything together I have an issue where the chain starts jumping over the cog when I put power on it. At low power(under 100 watt) there are no issues.
Did someone experience this? I’d be greatful for any suggestions.
If you used a chain that was worn past its wear limit of 0.5% with the Cog then that would have caused rapid wear to the Cog (and likely to your chainrings to a certain extent as well).
So now combining a new chain with a worn Cog would cause the symptoms that you describe.
Take it apart and check to see if thezwift cog is on tight. If it came loose and it’s cocking to the side under load if it could cause the chain to jump
I fixed the issue. Just replaced the ring with the teeth with a spare one from cog 1.5 which a friend of mine had as spare and worked ok. Probably the old ring was worn out together with the old chain. I guess I was lucky my friend had a spare. Thanks everyone for taking the time to respond!
I’m a bit surprised Zwift still hasn’t as yet put replacement cogs on their shopping site. You’d think by now heavy users would be about ready to need a new one. Of course you can source your own cog, but you’d still think Zwift would have this as a specific replacement part.
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I would contact support and ask them for a replacement. See what they say. Worst case the answer is no and a little time wasted.
Will do that and report back, but I’m not holding my breath. 
Thanks!