Bicycle Mechanics - High (low?) limit screw too short?

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pstock
08-29-11, 09:22 AM
I am having a bit of trouble getting this Chorus RD tuned.
it is just touching the spokes on the largest rear sprocket and I would like to back it off a bit.
But the limit screw, fully screwed in, doesn't engage with the stop bit.
what am I doing wrong?
I can't believe that I need a longer limit screw.

suggestions?

Peter


JiveTurkey
08-29-11, 10:22 AM
If you're trying to limit how far the derailleur can travel toward the spokes, then you adjust the Low (L) limit screw, since you're trying to position it under the low (largest) gear. So, make sure you're adjusting the correct screw. Is the other screw touching the derailleur body when in the largest gear?

Al1943
08-29-11, 11:52 AM
Also confirm that the chain is on the smallest chainring and largest cassette cog when adjusting the low limit screw.


pstock
08-29-11, 01:01 PM
thanks

But that is the Low LImit screw shown in the photo. screwed in all the way, it still doesn't catch the flang bit there.

Now, I notice that these High and Low Limit screws actually have springs on them, between the screw head and the derailleur body. when the screw is in as far as it can go, this spring is compressed and takes up enough space that the screw doesn't reach the flange.
if I remove that spring, I can get enough travel on the screw to hit the flange and keep the derailleur out of the spokes.

should I have to remove the Low Limit Screw spring?216603

JiveTurkey
08-29-11, 01:11 PM
Not personally familiar with Campy RDs so can't comment on that.

Look at the RD cage from behind. Does it look straight up and down, parallel to the frame/wheel? If it's bent in, that could explain why the L screw isn't doing anything. The RD hanger (or less likely the derailleur itself) may be bent in.

Al1943
08-29-11, 02:39 PM
It's hard to tell what is going on from the picture. If the bike is upside down turn it right side up and take a few more pictures, especially one from the rear. I was also wondering if the derailleur or derailleur hanger could be bent.

ultraman6970
08-29-11, 05:24 PM
Looks like u have more turns in the screw, IMO. Always what u can do is to put a spacer between the wheel and the cassette to move it out a few mm. Is that a 9 speed setup?

vredstein
08-29-11, 07:58 PM
I am having a bit of trouble getting this Chorus RD tuned.
it is just touching the spokes on the largest rear sprocket and I would like to back it off a bit.
But the limit screw, fully screwed in, doesn't engage with the stop bit.
what am I doing wrong?
I can't believe that I need a longer limit screw.

suggestions?

Peter

Install a longer screw.

rm -rf
08-29-11, 08:09 PM
How many cogs do you have? Are you on the largest cog (of 5?) in the photo?

Yes, that is the correct limit screw, and it's already extended far more than is typical. If your cog set is only 5 speed, is it narrower than what the derailleur was designed for?

More pics, please. A view from the back of the bike, and a side view, etc.

paulkal
08-30-11, 01:34 AM
That is an older Chorus RD. In the early 90s, they came with an extra longer screw in the box for 7 speed freewheels. So it is possible that ypu need a longer screw.

pstock
09-01-11, 03:42 PM
and it currently has an 8 speed wheel

vredstein
09-01-11, 04:05 PM
and it currently has an 8 speed wheel
From those pics, your derailleur hanger looks bent inward.

Al1943
09-01-11, 04:48 PM
From those pics, your derailleur hanger looks bent inward.

+1
The derailleur hanger appears to be bent inward and possibly twisted a bit.

ultraman6970
09-01-11, 05:07 PM
+1 if you cant notice would be good to get bifocals man.

pstock
09-01-11, 07:46 PM
+1 if you cant notice would be good to get bifocals man.

sorry, i've got a crap camera. I'll endeavor to get a better one.