Bicycle Mechanics - new cogset; derailleur going into spokes

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EEEOOO
10-18-06, 06:16 PM
I just switched from a 13-34 tooth freewheel cogset to a 13-22 tooth freewheel cogset and suddenly the guide pulley is rubbing against the disk which protects the chain from going into the spokes and the tension pulley is making some contact with the spokes when I am on the largest sprocket. I've adjusted the B-screw and that doesn't help. The hanger does appear to be very slightly bent, but it seems like even adjusting that wouldn't help. From eyeballing it, it looks like there simply isn't enough room between the largest sprocket and the spokes for the derailleur to get the chain all the way to the 22 tooth sprocket. Right now I have the L-limit set so that I can't hit the lowest gear, but this is kind of a pain.

Why would this suddenly occur with a smaller cogset? Could I need some sort of spacer to move the cogset farther from the spokes?


John E
10-18-06, 07:21 PM
Welcome to the forum! Do you have a screw-on freewheel or a modern freehub? With the former, it is trivial to add a narrow spacer to move your chain farther from the spokes.

EEEOOO
10-19-06, 06:48 PM
Thanks. It's a screw-on freewheel because I kick it old school. I think I'm going to try having the hanger straightened and then see if that helps. Oddly enough I was on the toilet when it occured to me that a smaller sprocket would make a bent hanger more of an issue. What I didn't understand was why the problem would suddenly arise with a smaller cogset, but it makes sense to me now.


Old Hammer Boy
10-19-06, 07:36 PM
You should also resize your chain, in case you haven't...

cs1
10-20-06, 02:43 AM
If the frame is steel, you can bend the hangar. Don't attempt that on aluminum. Take the bike to a shop with a der hanger guage. They can align it in a snap. Be prepared for a little frustation finding a shop though. With the advent of non repairable aluminum frames, most shops don't provide the service anymore. You might have to make a lot of calls or drive a ways to find a shop. I have a guy down the street from me, Clev OH area, that can do it. Good luck.
Tim