Bicycle Mechanics - Rear derailleur rubbing on pulleys - adjustment help?

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jimmy0x52
03-20-10, 12:18 PM
I've looked and looked and can't find info on this. I don't think it's a bent derailleur mount as the whole thing doesn't look out of wack - just the bottom pulley. When I have the RD in the highest gear it rubs a TON on the lower pulley's bracket/housing - so much so that it fakes me into thinking i'm in between gears and - if i'm going fast enough - actually jumps it around. Needless to say - super annoying.

Is there any adjustment I can make to fix this - or is it indeed the mount on the frame itself? From the pics - the bottom is the most helpful. Is there an adjustment?

It's a Shimano 600 RD - except the back wheel, hub and cassette is a wally world special (i'm replacing) - and it's an 80's Bianchi frame so I've got the rear wheel cold set into the back as well.

Also - bike was upside down on the ground so don't let the pics confuse you. I tried to get the angle as best I could so you could see what I was talking about.

Lastly - full disclosure - I'm a total bike noob. I got this about 5 days ago off craigslist and am working on making it ride well so I can commute with it. I had a friend help me pick it out and am learning myself. I've been reading a ton on SheldonBrown.com and have got the majority of the rest of the bike in adjustment - but this is confusing me.

http://stuff.jmia.net/bianchi/rd1.jpg

http://stuff.jmia.net/bianchi/rd2.jpg

DOS
03-20-10, 12:40 PM
I think the derailleur cage looks bent, but hard to tell from pics.
jimmy0x52
03-20-10, 12:44 PM
I was hoping it'd be something easy - i was thinking a similar thing after poking at it for a while.

anyone else concur?

reptilezs
03-20-10, 01:20 PM
hanger or derailleur is bent
DOS
03-20-10, 07:25 PM
hanger or derailleur is bent

If its the hangar, you or your shop likely can adjust with the park alignment tool. http://www.parktool.com/repair/readhowto.asp?id=39


If its the cage, I had same problem and could not ever get it right, so I replaced the derailleur.
AndrewP
03-20-10, 07:45 PM
If the derailler isnt bent, it may be that the chainline is bad. This can be fixed by replacing the bottom bracket with one with a longer spindle, so the chainrings line up with the middle of the cassette.
jimmy0x52
03-20-10, 07:46 PM
Well I tried messing with it tonight and found another problem - stem clamp bolt was stripped out and just about threw me over the bars when the clamp loosened and they dropped down.

Gotta love a craigslist bike. at least I got a deal on it.

Once I get a new stem and can ride it, I'll report back on any adjustments.