Zwift Hub One Chain Slip

Experiencing chain slip on zwift hub one after replacing chain on sram force 12s drivetrain. Found other threads on the forums and followed suggestions of microadjusting derailleur, cleaning drivetrain, and inspecting entire set up. I think I’ve narrowed down the issue to the worn out teeth on the zwift cog that comes with the zwift hub one.

My issue now is how to go about verifying or fixing this issue. In my research it looks like Zwift or Jet Black at one point offered a XDR freehub body compatible with the Zwift hub but now it is impossible to find in stock anywhere, so the option to swap to a XDR freehub and traditional 12s cassette is out of the question.

The next option appears to be to order a replacement 14s single cog, however according to someone that works at Zwift there’s many different 14T SS sprocket widths out there, and if I do do find a close match it won’t quite be the perfect fit with Cog’s mating parts.

Finally that brings me to a final option of either contacting zwift or ordering a zwift cog v2 for $80 from the zwift website. According to some individuals that faced a similar issue, they were provided a free cog v2 replacement once they contacted zwift and provided a serial number and photos of wear from their original zwift cog v1. I have sent an email to zwift support but have not heard back yet.

Has anyone faced this issue? My most pressing thought is if this is bound to happen again in another 6-8 months of normal use once I receive the new cog v2. Does anyone know if this is caused by an issue of using 12s flat top chains on the zwift cog v1 or if the revision of the tooth profile on the cog v2 solves the accelerated wear to the cog? Thanks

Was your chain new or very nearly new when you started using the Cog? Because a worn chain and new Cog is a recipe for rapid Cog wear.

Hi @Kris_DeVito welcome to Zwift forums.
+1 to what Steve said. Chains and cogs will inevitably wear out.

If your new chain skips on the Zwift Cog - chances are the old chain wore out the ZCog. This happens with multispeed cassettes too - a worn chain grows slightly in length at each rivet, and the distance between chain rollers as a result. In turn, each roller chews deeper into the “valley” between the cog teeth. A Zwift Cog v2 has built-in chainline adjuster so you can adjust the cog’s side to side position, rather than adjusting the derailleur’s side to side position. This make it so your derailleur’s position is still dialed in for your rear wheel for outdoor riding.

If you threw out the old chain - it’s a little too late to objectively measure how much that chain grew in length. For future reference - you should buy a chain wear indicator tool. Pedros and Park Tools both make one that’s compatible with SRAM 12 speed chains. These chains have rollers that are slightly larger in diameter than standard, as you may be aware.

Every chain wears out eventually. If you’re in the habit of using this tool, you can replace a chain before it also damages your cassette and chainrings. 12 speed chains are not cheap, but cassettes and chainrings are even more expensive.

Will Zwift sell the Cog without having to buy another shifter as well? I don’t see it in the catalog.

No, that is the 3rd paragraph I wrote on trying to source just the 14s single cog.

You have to buy the cog v2 for $80 with the virtual shifting controller.

Or buy a singlespeed conversion kit for $20.

I check chain wear at least monthly w/ park tool indicator, there was some chain wear but it wasn’t significant or anything out of the ordinary. Just enough to warrant replacing with a new chain. I guess what I’m asking are more of:

  1. Is there accelerated wear due to use of a sram 12s flat top chain with the cog v1 that would put the life expectancy of the cog at around 4K miles

  2. Do we know if the revised tooth profile of the cog v2 has anything to do with compatibility with sram 12s flat top chains and/or improving the product life of the cog v2

The life expectancy of the cog v2 is stated to be somewhere around 25K miles, assuming no accelerated wear due to compatibility issues or usage with significant chain wear

This entire thread is about single speed cog I don’t understand what you mean by single speed conversion kit for $20

Cog, spacers, $20. No reason to buy the Zwift one if you already have Zwift Play and don’t need the click shifter.

same issue as cog v1, tooth profile of any single cog is not intended for use with sram 12s flat top chain and the wear of the cog will be accelerated. sram axs cassettes only come in 1 piece. It would be a temporary solution and I guess I could continue to swap out the cog every time it wore down and I experienced chain slip but thats pretty annoying. Also annoying to try to find the right combination of spacers for the correct chain line.

@Paul_Southworth you are correct. Zwift Cog has always been sold with a Click shifter.

@Kris_DeVito contact my Support colleagues and they’ll work something out for you.

Updating this thread for anyone in the future that stumbles upon it, the zwift tech support sent me the cog v2, I swapped it out for the v1, and it ran perfectly with a sram 12s chain. I will update the thread if I have accelerated/premature wear on the cog v2