Rear derailleur rubbing on spokes
03-28-19, 11:43 AM
#1
Sr Member on Sr bikes
Thread Starter
Rear derailleur rubbing on spokes
Someone see if you can explain this conundrum. It wasn't happening before the recent maintenance I did. I had to replace the rear wheel ballbearings and cone nuts. There was no problem with all of that. But then when I rode the bike, when in the largest gear, the inside of the derailleur cage would slightly rub on the spokes. Shifting was otherwise fine. I adjusted the limit screw...which I really didn't have much play with because too much adjustment and then it wouldn't shift up to the biggest gear. But, it still rubs...ONLY when I'm riding (i.e. climbing a hill). When I put the bike on the work stand...it doesn't rub. In fact, when it's on the stand, if I shift to the biggest gear, and then push on the derailleur...I can't even put enough pressure on it to make it rub. So why is it rubbing when I ride?
Dan
03-28-19, 12:27 PM
#2
Full Member
Is there any play from the axle in the hub body? It could be that they are not tight enough and the play only shows up under load. just a thought I dont really know how that could happen either.
03-28-19, 12:40 PM
#3
Steel is real
Post a pic?
Was there a washer you forgot to place? you may have brought the wheel over a bit to the right
Was there a washer you forgot to place? you may have brought the wheel over a bit to the right
03-28-19, 02:03 PM
#4
Sr Member on Sr bikes
Thread Starter
And I do want to point out that it's only very slightly rubbing when it does. I'm not in any danger of completely destroying the wheel/derailleur (I don't think I am). But I can definately hear it rubbing ever so slightly. On the stand, when I have it on the largest gear...there is about one-eighth inch clearance between the derailleur and the spokes.
Dan
03-28-19, 02:08 PM
#5
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Did you take the cassette off.... is there a spacer on the cassette? How many speeds are you?
03-28-19, 02:11 PM
#6
Steel is real
I'd keep adjusting the RD limit screw then so it clears
park tools has an excellent video on this on youtube
park tools has an excellent video on this on youtube
03-28-19, 02:15 PM
#7
Steel is real
there's also a possibility your RD cage is bent or your RD hanger
03-28-19, 02:40 PM
#8
Sr Member on Sr bikes
Thread Starter
Yes and yes. Seven gears. But simply taking the cassette off shouldn't make a difference. It wasn't doing this prior to my hub maintenance, it's still shifting properly post-maintenance, and I didn't adjust the limit screws during the maintenance (only slight adjustment since just to decrease the rubbing).
Dan
03-28-19, 03:16 PM
#10
Steel is real
03-28-19, 05:22 PM
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Since it only rubs under load, it sounds to me as if the hub is adjusted too loosely. Basically, you should have a little play with the QR lightly engaged, play should disappear when you tighten the QR.
03-28-19, 05:24 PM
#12
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Same problem happened here after overhauling an 8sp campy, a tiny limit adjustment fixed it. It still feels weird though, as if the cable tension was too high.
03-28-19, 07:51 PM
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AHA. SOMEWHERE I CAN BE USEFUL.
Your spokes are too flexy. Sounds idiotic. But I bet it’s true. If you look at your “pulling” drive spoke, it’s probably on the “inside” of the cross with the “pushing” spoke on the drive side. This means that when you yeet, the inside (pulling) spoke tenses up and pushes up against the outer (“pushing”) spoke. This causes the cross of the two spokes to push towards your derailleur cage. When climbing in your easiest gear, this flex is enough to cause rub.
Do you, by any chance, have a specialized bike with round spokes (as opposed to a top end wheelset with aero spokes)?
EDIT: never mind with the specialized comment. Just saw that you have a 7 speed bike. So I assume it’s older. I have no idea why this problem never arised before. I could be way off base here if you really never had this problem before and didn’t change anything about your spoke setup.
Your spokes are too flexy. Sounds idiotic. But I bet it’s true. If you look at your “pulling” drive spoke, it’s probably on the “inside” of the cross with the “pushing” spoke on the drive side. This means that when you yeet, the inside (pulling) spoke tenses up and pushes up against the outer (“pushing”) spoke. This causes the cross of the two spokes to push towards your derailleur cage. When climbing in your easiest gear, this flex is enough to cause rub.
Do you, by any chance, have a specialized bike with round spokes (as opposed to a top end wheelset with aero spokes)?
EDIT: never mind with the specialized comment. Just saw that you have a 7 speed bike. So I assume it’s older. I have no idea why this problem never arised before. I could be way off base here if you really never had this problem before and didn’t change anything about your spoke setup.
03-28-19, 08:16 PM
#14
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But first, as suggested, re-adjust the bearing preload.
The new cones are not exactly the same dimension as the old. Follow the RD procedure completely and in sequence, including indexing.
03-28-19, 09:06 PM
#15
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Thread Starter
AHA. SOMEWHERE I CAN BE USEFUL.
Your spokes are too flexy. Sounds idiotic. But I bet it’s true. If you look at your “pulling” drive spoke, it’s probably on the “inside” of the cross with the “pushing” spoke on the drive side. This means that when you yeet, the inside (pulling) spoke tenses up and pushes up against the outer (“pushing”) spoke. This causes the cross of the two spokes to push towards your derailleur cage. When climbing in your easiest gear, this flex is enough to cause rub.
Do you, by any chance, have a specialized bike with round spokes (as opposed to a top end wheelset with aero spokes)?
EDIT: never mind with the specialized comment. Just saw that you have a 7 speed bike. So I assume it’s older. I have no idea why this problem never arised before. I could be way off base here if you really never had this problem before and didn’t change anything about your spoke setup.
Your spokes are too flexy. Sounds idiotic. But I bet it’s true. If you look at your “pulling” drive spoke, it’s probably on the “inside” of the cross with the “pushing” spoke on the drive side. This means that when you yeet, the inside (pulling) spoke tenses up and pushes up against the outer (“pushing”) spoke. This causes the cross of the two spokes to push towards your derailleur cage. When climbing in your easiest gear, this flex is enough to cause rub.
Do you, by any chance, have a specialized bike with round spokes (as opposed to a top end wheelset with aero spokes)?
EDIT: never mind with the specialized comment. Just saw that you have a 7 speed bike. So I assume it’s older. I have no idea why this problem never arised before. I could be way off base here if you really never had this problem before and didn’t change anything about your spoke setup.
Dan
03-28-19, 11:55 PM
#16
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To rephrase that paragraph: if your spokes are very elastic, when you pedal hard, the spokes on the drive side will flex outwards. This can cause rub. It’ll sound like pinging, and it’ll only happen on climbs or when accelerating hard. I had the exact same symptoms which is why I thought that would be it.
One thing I will say is that, from what I know about cup and cone bearings, if you took off and reinstalled both cones, then it’s possible that the wheel is further to the drive side than it was before. Can you move the left cone outward and the right cone inward, thus moving the wheel away from the derailleur? Just throwing out ideas here...
Also, if you used new bearings, what size bearings did you use?
good luck...
03-29-19, 07:10 AM
#17
Sr Member on Sr bikes
Thread Starter
Yeah ok. Sorry for getting excited. If your wheelset is by Shimano and it’s laced 3 cross, then I suppose spoke flex is unlikely to be the culprit - especially considering that it mysteriously happened after hub service.
To rephrase that paragraph: if your spokes are very elastic, when you pedal hard, the spokes on the drive side will flex outwards. This can cause rub. It’ll sound like pinging, and it’ll only happen on climbs or when accelerating hard. I had the exact same symptoms which is why I thought that would be it.
One thing I will say is that, from what I know about cup and cone bearings, if you took off and reinstalled both cones, then it’s possible that the wheel is further to the drive side than it was before. Can you move the left cone outward and the right cone inward, thus moving the wheel away from the derailleur? Just throwing out ideas here...
Also, if you used new bearings, what size bearings did you use?
good luck...
But...what I'm thinking now is perhaps the replacement cone nuts I used might not have the same thickness as the original cones had. Maybe it's only a couple thousandths on each cone. The hub serial number is no longer produced/supported by Shimano so I had to go with a recommended replacement part. If that's the case, maybe when the QR is tightened it pushes the frame together just those few thousandths more...just enough to make the derailleur just close enough to rub on the spokes.
Dan
03-29-19, 08:05 AM
#18
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It's fun to speculate about all the possible causes but if you want to solve the problem you must take an organized approach. Eliminate the simple and obvious first. Grab the wheel at the top and rock it. Report back
03-29-19, 11:53 AM
#19
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Loose spokes are not likely to me, but check that. It's probably that your derailleur hanger is bent in as @le mans says. Look at your derailleur from behind when your bike is perfectly upright. Is the derailleur cage perfectly vertical? I bet the bottom end is leaning inwards. Get this fixed at a bike shop, because you are in danger of shifting your spokes into your wheel which will cause a nasty accident and costly repairs.
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03-29-19, 12:16 PM
#20
Sr Member on Sr bikes
Thread Starter
No, neither the derailleur hanger, nor the derailleur are bent. There was no rubbing prior to the wheel hub maintenance I did replacing the ball bearings and the cone nuts. Nothing happened to the bike while I was doing the maintenance on the wheel. It remained on the work stand. When I finished and put the wheel back on the bike, and rode it, is when the rubbing started. I'm still thinking that the new cones must be just a fraction thinner than the old ones were. Therefore, when I clamp the QR it brings the chainstay/seatstay/dropouts (on which the derailleur hangs) that much closer to the spokes. So I'm thinking that putting a small spacer (washer) in there on each side will keep it from clamping in so close to the spokes, and hopefully stop rubbing from happening.
Dan
Dan
Last edited by _ForceD_; 03-29-19 at 12:22 PM.
03-29-19, 01:42 PM
#21
Steel is real
Just check the axle spacing, easy way to check is to undo the skewers and see if there are gaps either side of the dropouts
it should slip in nicely, not too tight - not too loose
you may have fitted thinner lock nuts, if so i would just put the old ones back on
it should slip in nicely, not too tight - not too loose
you may have fitted thinner lock nuts, if so i would just put the old ones back on
Last edited by le mans; 03-29-19 at 01:54 PM.
03-29-19, 02:08 PM
#22
Steel is real
That is the foremost area i make sure is correct when building a bike
So when i have RD tuning problems that can be eliminated, i fix and flip a fair few bikes, on a hybrid the RD cage was rubbing on the spokes, so i could look at other areas, took the RD off and found the hanger needed to be aligned, did that and it still rubbed, looked at the RD from behind to discover that was bent too, wanted to use this nice RD but had to choose another one
So when i have RD tuning problems that can be eliminated, i fix and flip a fair few bikes, on a hybrid the RD cage was rubbing on the spokes, so i could look at other areas, took the RD off and found the hanger needed to be aligned, did that and it still rubbed, looked at the RD from behind to discover that was bent too, wanted to use this nice RD but had to choose another one
Last edited by le mans; 03-29-19 at 02:11 PM.
03-29-19, 02:47 PM
#23
Senior Member
Could be any number of things, most have already been mentioned.
Try this>> Check the depth of the old cones to the new ones. Check that the ball bearings are same diameter as the old ones.
--
Try this>> Check the depth of the old cones to the new ones. Check that the ball bearings are same diameter as the old ones.
--
Last edited by drlogik; 03-29-19 at 02:51 PM.
03-29-19, 03:52 PM
#24
Full Member
If you suspect hub width has changed, just measure it. If it is a 7 speed road bike it should be 130 mm outside of the lock nuts to outside, and a 7 speed mountain bike should be 135 mm. If it is narrower than this the new cones must have been narrower. Add appropriate washers to each side. Note that the frame should be the same as the hub unless it has been sprung in or out.
03-29-19, 05:41 PM
#25
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AHA. SOMEWHERE I CAN BE USEFUL.
Your spokes are too flexy. Sounds idiotic. But I bet it’s true. If you look at your “pulling” drive spoke, it’s probably on the “inside” of the cross with the “pushing” spoke on the drive side. This means that when you yeet, the inside (pulling) spoke tenses up and pushes up against the outer (“pushing”) spoke. This causes the cross of the two spokes to push towards your derailleur cage. When climbing in your easiest gear, this flex is enough to cause rub.
Do you, by any chance, have a specialized bike with round spokes (as opposed to a top end wheelset with aero spokes)?
EDIT: never mind with the specialized comment. Just saw that you have a 7 speed bike. So I assume it’s older. I have no idea why this problem never arised before. I could be way off base here if you really never had this problem before and didn’t change anything about your spoke setup.
Your spokes are too flexy. Sounds idiotic. But I bet it’s true. If you look at your “pulling” drive spoke, it’s probably on the “inside” of the cross with the “pushing” spoke on the drive side. This means that when you yeet, the inside (pulling) spoke tenses up and pushes up against the outer (“pushing”) spoke. This causes the cross of the two spokes to push towards your derailleur cage. When climbing in your easiest gear, this flex is enough to cause rub.
Do you, by any chance, have a specialized bike with round spokes (as opposed to a top end wheelset with aero spokes)?
EDIT: never mind with the specialized comment. Just saw that you have a 7 speed bike. So I assume it’s older. I have no idea why this problem never arised before. I could be way off base here if you really never had this problem before and didn’t change anything about your spoke setup.