chuckb

I'm having an issue with the rear derailleur setup on SRAM Red (the original red, not the 2012 version). The problem is that the derailleur cage is always slightly misaligned with some of the rear cogs no matter how I change the barrel adjuster.

The cage should always be exactly in the same plane of each cog as I shift up and down the rear cluster. What actually happens is that I can tighten/loosen the barrel adjust to make this precisely true at the top of the cluster (large cogs) or the bottom of the cluster (small cogs), but NO setting of the barrel adjust keeps the movement of the cage completely in the plane of every gear on the cluster. So, I compromise and shift up/down the cluster many times and turn barrel adjust until it's a little off at the top and a little off at the bottom. That comes out "okay", but just barely.

So, I need to do something else, but what? I'm still learning this, but it seems like the size of each shift (ie, the displacement of the cage each time) is just not right so the cage gradually gets out of phase with the spacing of the gears on the rear cluster.

Suggestions for a novice?

dsbrantjr

Is the cable properly attached to the anchor bolt? According to the 2010 model manual it needs to pass above the bolt and washer tab (page 8, Fig.6) If you run it below it may change the length of the lever arm and thus the amount of derailleur movement per unit of cable pull/shifter click. This is the "alternate cable routing" sometimes mentioned. I am assuming that you have the correct shifter for this derailleur.

Here's a link to the document: https://cdn.sram.com/cdn/farfuture/SB...nual-rev-a.pdf

rdtompki

I'm assuming the shifters are compatible with the RD? The newer RD, road and MTB, are Exact Actuation, and have a difference actuation ratio than the prior generation (I believe). It also sounds like your procedure for adjusting the RD might need some tweaking. I'd look over Park Tools or Sheldon.

JTGraphics

Start from the beginning remove the cable from the RD,
Shift lever all the way down so it would be on the small cog.
Now adjust low limit screws align the jockey wheel with the small cog
Push RD with your thumb all the way to the large cog set the hi limit screw so jockey wheel line up with and stops so its lined up also.
You can also set B screw at this point also.
Let it go make sure any barrel adjusters are screwed in bot on RD and if you have one on frame down tube.
Reattach the cable make sure its routed correctly.
Remove excess slack from cable with barrel adjuster.
Click lever up one cog, if it does not move up while turning crank turn a barrel adjuster CCW till it does.
Shift lever one more time to next gear it should move if its slow going up turn barrel adjuster CCW.
At this point it should go thru all gears Fine tune with barrel adjuster to remove and noise in RD it should be very close no more that 4-5 turns onE way or the other.


Now at this point if you still have serious issues something else is wrong, bent hanger, worn inner and or outer cable housings or cable routing is not correct it make a difference how the cable is routed in RD at the clamp make sure its right but Sram its kind go hard to gut it wrong.

Also not sure on what you have but 10 speed must be matched with 10 speed as well as 9 with 9 is it you can not mix them up.

berner

There could be a mis-match in the derailler as suggested. I had a similar problem with a new bike that got very frustrating to solve. Near wits end, I finally found that the bushing on which the derailler hung had too much play and would not stay in proper alignment. This was discovered after some months of frustration. The solution for a bad bushing was a new derailler. Good luck.