Bicycle Mechanics - Derailleur Hanger -- really aligned?
Bikeforums.net is a forum about nothing but bikes. Our community can help you find information about hard-to-find and localized information like bicycle tours, specialties like where in your area to have your recumbent bike serviced, or what are the best bicycle tires and seats for the activities you use your bike for.
09-16-11, 07:47 PM
I've had index shifting problems ever since I've had this bike. I got a Park DAG-2 a while back, adjusted everything seemingly perfect, and shifting got better but still not reliable enough to use indexing (friction works fine).
The symptom I have is seemingly perfect indexing 90% of the time, then sudden "pop" noises of the chain not being properly aligned with the cogs.....then a long time with nothing, then it happens again, etc. I've tried several different chains and cassettes -- same problem.
I looked at the hanger upside down and can clearly see that the derailleur and hanger don't appear to be parallel.
Is this normal? I double checked and the 4 cardinal directions lined up with the tire valve are within 2 mm of each other (perfect - according to the tool).
Should I trust my instinct and make the hanger look more parallel even though the tool says otherwise?
09-16-11, 08:18 PM
The question might be if the bolt on the RD is straight? or is the RD straight? With an old RD, I noticed some play in the bolt that would allow it to pivot a few degrees. So even if the RD hanger is perfect, the RD may not be. And many have a spring plate that the B-screw is attached to that is the facing plate that actually rests on the RD hanger. That plate may result in the whole RD being ever slightly out of plane. I recently bent a vintage frame RD hanger out by 3 degrees out at the bottom, and then gave it about 5 degrees of yaw to port if standing behind and looking forward along the frame. Perfect indexing with an old Shimano RD6207 (600 EX SiS first generation) and BR3300 left/right 7 spd and SunRace 7 spd.
Old Hammer Boy
09-16-11, 11:23 PM
I would also check the R/D cable, especially under the bottom bracket where things can get pretty gunky. It may be time to replace the complete cable assembly, both sleeve and inner cable. If that doesn't do it, it most certainly will be the R/D. Good luck and let us know what you find...
TurbineBlade, I've had a similar issue, I think, with two different bikes in the past. On a roadie the cable housing cap had split (plastic) at the RD. This was the first time I'd used shifter specific housing and I moved the metal cap I'd installed on the chainstay to the RD and a spare plastic cap to the chainstay. On the mountain bike the jockey and tension wheels required removal and a clean/relube inside and out, my fault as they were filthy.
Take the rear derailleur off, then put a spare hub in the dropout and tighten the skewer nice and super tight. Then use a digital caliper to measure whether the hanger is parallel at it's whole length with the hub flange.
09-18-11, 07:43 AM
Wow, that looks way off. I'm surprised your DAG-2 told you it was parallel with the wheel. You might want to check again. BTW, how true is your wheel (though it would have to be way off to make a diff)?
Powered by vBulletin® Version 4.1.12 Copyright © 2013 vBulletin Solutions, Inc. All rights reserved.