On my newly converted bike with TSDZ02 motor, I had a bit of a problem today. Every time I was going fast freewheeling down steep hills and went over a bump, I got an extreme rubbing noise, like when you get a twig under the mudguard, but every time I stopped to check it out, it disappeared just before I stopped. It was very frustrating. It sounded like it was coming from the front mudguard., though I couldn't see any way it could happen, and I couldn't reproduce it by bouncing the front wheel.
Finally, I stuck my head right down when it was doing it, and I could hear it was coming from further back, then I saw the bottom run of the chain loose and rubbing on the back tyre.
The cause was the freehub, not running free. It was sort of free, but if you span it fast and jiggled it, it would make a sort of resonating noise and stop quickly, like a dry bearing. In that situation, which got triggered by any bump when freewheeling fast, the cassette was being turned by the wheel, which wound the chain back and pulled the derailleur forwards. The derailleur has a clutch. I think that might have something to do with it as well. This was also making the chain jump off completely in about 50% of cases.
I was a about 10 miles from home, so I had to adapt my pedalling. As long as the pedals were turning. It wouldn't do it, so I had to keep pedalling when going down very steep hills, which was a bit weird. It's not as easy as it sounds. Try riding your bike 10 miles without free-wheeling.
I opened it up to check inside, but everything seemed OK. The bearings were good, so I put a bit of oil on the pawls and reassembled it, after which it ran smooth as silk.
There have been a couple of threads recently about chains jumping off, so I'm wondering if a stiff freehub or freewheel could be a factor. It's very easy to get dirt, grass a twig or anything like that behind the gears, which would also cause it.
Finally, I stuck my head right down when it was doing it, and I could hear it was coming from further back, then I saw the bottom run of the chain loose and rubbing on the back tyre.
The cause was the freehub, not running free. It was sort of free, but if you span it fast and jiggled it, it would make a sort of resonating noise and stop quickly, like a dry bearing. In that situation, which got triggered by any bump when freewheeling fast, the cassette was being turned by the wheel, which wound the chain back and pulled the derailleur forwards. The derailleur has a clutch. I think that might have something to do with it as well. This was also making the chain jump off completely in about 50% of cases.
I was a about 10 miles from home, so I had to adapt my pedalling. As long as the pedals were turning. It wouldn't do it, so I had to keep pedalling when going down very steep hills, which was a bit weird. It's not as easy as it sounds. Try riding your bike 10 miles without free-wheeling.
I opened it up to check inside, but everything seemed OK. The bearings were good, so I put a bit of oil on the pawls and reassembled it, after which it ran smooth as silk.
There have been a couple of threads recently about chains jumping off, so I'm wondering if a stiff freehub or freewheel could be a factor. It's very easy to get dirt, grass a twig or anything like that behind the gears, which would also cause it.
