Curled up rear derailleur
Hi there! I’m new to the forum.
So I have a trek road bike which is about 8/9 years old with shimano 105 front and rear derailleurs.
My problem is with the rear. I removed it from the frame recently for cleaning and removed the pulley wheels also.
Now when I try to tune the gears, when the chain is on the small chain ring and on the smaller cogs of the cassette, the derailleur curls upwards and starts jumping (as in the chain doesnt pass smoothly through the 2 pulley wheels).
One important point is that while re-inserting the top pulley wheel, I had to install it without the two metal washers since the screw seemed to not have enough thread. The three parts simply didnt fit. Maybe this is another reason for the instabilityPosted 4 years agocyclicalMember
If you look at another rear mech you will see that there is no overlap on the screws that hold the pulley wheels ie the screws aren’t made on the long side. Once you have put the metal washers in you really have to nip the mech together with your other hand to pull everything together before the screw will catch in the thread. Once the screw has caught it will pull everything together. Don’t over tighten though or else you may have the same problem as you have nowPosted 4 years ago
Wow, thanks very much to all for the replies!
@bencooper – yeah I was pretty much expecting there to be problems when I wasn’t able to put it all back together again.
@brokensoul True! 🙂
@leftyboy I’m pretty sure i didnt mix up the parts – just left out the 2 metal washers that go either side of the jockey wheel…but i’ll have a look to make sure.
@cyclical “Once you have put the metal washers in you really have to nip the mech together with your other hand to pull everything together before the screw will catch in the thread.”
Exactly what I tried to do but I couldn’t get it to bite :-/
@VanMan Awesome links! thanks a million.
In the meantime here are 2 photos to illustrate a bit more the problem I have.
In the first you can see how there is a lot of slack in the chain when I have it on the smallest cog.
And in the second, you can see how the arm of the derailleur is completely curled up.
PS: Let me know if you can’t access the photos. On clicking the “IMG” button it asked me for a url – thats why I used dropbox.Posted 4 years ago
Basically the tension in the chain is what pulls the mech forward – its natural position is just as it is in the photos. As the chain appears to be on both the cassette and the chainring that seems the obvious problem.
Can you take a photo on the big ring for comparison?
The missings parts from the jockeys won’t be helping at all too!Posted 4 years ago
Hi again guys,
@markie, i replaced the gear shifter cable since its been ages since it was changed and i just followed a youtube video to try to tune the gear shifting.
@njee20 yup! you’re right – the chain is brand new, the cassette too. Now that i think of it i didnt check the length against the old chain to make sure there was no excess.
I know what you mean about the chainring, but it shouldn’t be curled up like that when its on the small ring?
@adambikeworks Njee20 is right – its a turbo trainer skewer. I managed to lose the original mavic one so i left it in.
here are the photos you asked for, one with the chain on the big ring and the second with the wheel removed looking at the other side of the mech.
Posted 4 years ago
here they are again, let me know if you still cant access them…Posted 4 years ago
Hi again everyone…
Sure enough I checked the new chain against the old and it was a good 5 or 6 links longer.
So I took them out and it seems to be running as before, smooth and the derailluer doesn’t curl up in any gear ratio.
I tried putting the metal washers back around the jockey wheel but it was imposible. The thread must have worn on the screw or on the mech, either way it just doesnt want to fit.
But there doesn’t seem to be a lot of play so its fine as it is I think.
The mech is a good 8 years old now with a lot of km’s put into it, so the gear shifting isn’t as smooth or as accurate as it should be but i was planning on upgrading to a brand new ultegra anyway. It’s in bad need of it.
Thanks to everyone for the help, really appreciate it!Posted 4 years ago
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