Chain tension problem

[jonozrx]

Hi all

I've noticed recently that my chain has been working itself loose during races. The pinch bolt is always tight, and the problem seems to be getting worse and worse - the chain actually jumped off during an endurance race on the weekend.

Is this a common problem? What could be causing it? I really want to get this fixed, as it's not very confidence inspiring!

Any help will be greatly appreciated

Edit - should probably mention that the bike is an NC30.

[superlite]

Sounds unusual and unlikely to be a fault of the chain adjustment system. What make/model of chain (and sprockets) are you running? I'm assuming you've spent wisely and bought a quality chain?

[jonozrx]

Not sure what brand they are, but they are reasonably new and in good condition. The bike doesn't actually live with me, so I'll check out the brand this weekend.

[Neosophist]

Is your hub assembled properly / worn out?

If the chain / sprockets are not at fault your hub could be slipping

[Mananon]

You didn't grease the assembly while apart did you? A lot of energy going through those parts in a race. Anti seize is ok but not grease.
I've read a thread somewhere where a guy was having the same problem on the road due to this.

[jonozrx]

Is your hub assembled properly / worn out?

If the chain / sprockets are not at fault your hub could be slipping

Pretty sure it's assembled properly, so I'm beginning to think it could be worn out. If I pull it apart would the wear be obvious? What sort of damage etc should I be looking for?

You didn't grease the assembly while apart did you? A lot of energy going through those parts in a race. Anti seize is ok but not grease.
I've read a thread somewhere where a guy was having the same problem on the road due to this.

I've never actually disassembled it before, but seeing as it's only started slipping recently I don't think it would have been greased.

[Cammo]

I used to have this problem on my first nc30. Never did solve it as it was a roadbike, I just lived with the problem.

[Neosophist]

Get the hub out and have a look.

Shouldn't be too hard to see major wear on the outside of it.