So about two weeks ago the pins supporting my rear mudguard jumped out of the clasps, got caught in the cassette or spokes and ended up destroying the rear derailleur and bent the integrated hanger quite badly. LBS did some corrective action as can be seen in the 2nd pic, but left the hanger (probably) parallel to the body but not in the same position as it was originally…
My new rear derailleur is MTB style, and while I think the limit screws might be enough to shift the entire cassette still (?), the notched part of the hanger for the road style RD B-screw seems to be at an odd angle to the plane of the RD mounting screw… The part of the RD that is supposed to be set against the notch is only ~2,5 mm wide, and because of the angles it’s only overlapping just shy of 1mm (0,8-0,9 mm) measured with a caliper.
Do I need to try to straighten the whole hanger and notch area to have the parts meet more? I can’t rotate the RD forward by hand past the notch, but haven’t tried with too much force. There’s a layer of paint there, and I’m not sure how much metal to metal overlap there might be if the paint was scratched away…
uwootmVIII on
If you’re really into saving that frame, I would ask a frame builder to put it in his jig while straightening the hanger. The whole dropout looks kinda crooked.
CheapFuckingBastard on
If it shifts gears as it did before, then it’s straight enough. If your LBS was good, they’d have made the hanger parallel to the plane of your wheel.
If not, you can do a better job by acquiring a derailleur hanger tool – they can be had from Park or Aliexpress.
FarAwaySailor on
It’s only an 8spd is not as sensitive to hanger misalignment as 9/10/11/12s but as a general rule of thumb: if it looks bent, or you even *think* it might look bent, it probably is going to affect shifting.
The alignment tool doesn’t lie, and if they didn’t use one then they just guessed at straight.
Source: I’m a bike mechanic. I straighten hangers regularly.
TonyXuRichMF on
You need a “hanger alignment gauge.” The tool only works properly if the wheel is true, so you might also need a truing stand and spoke wrench.
csmdds on
No. Go to your LBS and ask them to check it with the derailleur hanger alignment tool. It needs to be close to perfectly parallel to your wheel and gear cluster.
That’s steel and should be pretty quick and easy. Not an expensive repair.
Paul_walker-treehugr on
Don’t suppose there’s a mount to convert to an opposite side drive on the bike? Could there be a possibility of a derailer mount
7 Comments
So about two weeks ago the pins supporting my rear mudguard jumped out of the clasps, got caught in the cassette or spokes and ended up destroying the rear derailleur and bent the integrated hanger quite badly. LBS did some corrective action as can be seen in the 2nd pic, but left the hanger (probably) parallel to the body but not in the same position as it was originally…
My new rear derailleur is MTB style, and while I think the limit screws might be enough to shift the entire cassette still (?), the notched part of the hanger for the road style RD B-screw seems to be at an odd angle to the plane of the RD mounting screw… The part of the RD that is supposed to be set against the notch is only ~2,5 mm wide, and because of the angles it’s only overlapping just shy of 1mm (0,8-0,9 mm) measured with a caliper.
Do I need to try to straighten the whole hanger and notch area to have the parts meet more? I can’t rotate the RD forward by hand past the notch, but haven’t tried with too much force. There’s a layer of paint there, and I’m not sure how much metal to metal overlap there might be if the paint was scratched away…
If you’re really into saving that frame, I would ask a frame builder to put it in his jig while straightening the hanger. The whole dropout looks kinda crooked.
If it shifts gears as it did before, then it’s straight enough. If your LBS was good, they’d have made the hanger parallel to the plane of your wheel.
If not, you can do a better job by acquiring a derailleur hanger tool – they can be had from Park or Aliexpress.
It’s only an 8spd is not as sensitive to hanger misalignment as 9/10/11/12s but as a general rule of thumb: if it looks bent, or you even *think* it might look bent, it probably is going to affect shifting.
The alignment tool doesn’t lie, and if they didn’t use one then they just guessed at straight.
Source: I’m a bike mechanic. I straighten hangers regularly.
You need a “hanger alignment gauge.” The tool only works properly if the wheel is true, so you might also need a truing stand and spoke wrench.
No. Go to your LBS and ask them to check it with the derailleur hanger alignment tool. It needs to be close to perfectly parallel to your wheel and gear cluster.
That’s steel and should be pretty quick and easy. Not an expensive repair.
Don’t suppose there’s a mount to convert to an opposite side drive on the bike? Could there be a possibility of a derailer mount