Originally Posted by Crankycrank

I agree with cxwrench that you're missing an axle cap. Novatec website doesn't offer much info on axle configuration so contact them and ask or visit your LBS with the wheel. Contact Us – Novatec 2021 (novatecusa.net) A photo of the drive side of the hub/wheel removed from the bike so we can see the axle would be helpful.