My belt-drive Trek's 8-speed Nexus hub gear is now unpredictably jumping when in 5th gear or higher. The pedals just leap forward by a bit and then the hub re-engages. Sometimes it's every 10 turns of the pedals; other times it's more or fewer turns. I'm guessing there are broken teeth on two gear wheels, and the hub jumps when the broken teeth line up.
I've replaced the cable, and tried adjusting the cable tension, both too tight and too loose compared to the "right" position (yellow marks aligned when in 4th gear), and it still jumps.
Is it totally b0rked? Do I need a new hub? Are they still available and compatible with the roller-brake, belt-drive pinion etc?
Suggestions please!
