I have a new chain on a used bike that has been working perfectly for 500km and the chain has started jumping a cog on every different speed. It definitely feels like a cog and chain slipping, the pedal falls forward and catches on again.
Can it be inside the rear wheel bearings? The chain is the only thing that can be faulty? It's by a good company and fairly new, and I couldn't see a fault on the chain. What can it be?