SRAM Rival 11-speed - Indexing Issues

arlowood

Took delivery of a Planet X London Road a couple of months back as a first foray into the world of SRAM gear systems. Have many years experience of Campag initially (Mirage triple on my Mercian steely for 14 years) and latterly Shimano over the past 7-8 years (105/Ultegra/ Dura Ace in various combo's on retail bikes and those I've built myself)

Initially got used to the double tap system pretty quickly and gear changes were fine in both directions. However recently I've experienced one or two issues and I'm struggling to sort them out.

Firstly I've noted that when shifting to a lower gear (ie operating the double click to move from smaller to larger sprocket) the chain will sometimes skip and move down two sprockets rather than one. Also, sometimes it appears to move down one sprocket very briefly then drops back into the higher gear.

Both of those problems suggest different causes - the first being maybe too much tension in the cable while the second suggests maybe not enough tension.

I've had a bit of a play with the barrel adjuster but I'm not sure if I'm just tinkering at the edges and should really go back and do a re-indexing from first principles. To that end I was wondering if the approach adopted for my fall-back Shimano set up would work.

That is -
1 Move chain to 11-tooth sprocket.
2 Detach cable from anchor bolt.
3 Ensure shifter is shifted as far as possible to the highest gear (smallest sprocket).
4 Wind barrel adjuster in fully.
5 Pull cable through with as much tension as you can manually then secure with cable anchor.
6 Operate shifter as if you were changing from the 11 to the 12 sprocket (doble tap/click).
7 Wind barrel adjuster out (anticlockwise) until the chain moves up to the 12 sprocket and apply and extra quarter turn to the barrel adjuster.
8 Check indexing across the block and tweak as necessary.

Can anyone confirm if this process will work OK with SRAM before I try it?

me-109

4. Wind the adjuster fully in, then back out a turn or two to give you adjustment in both directions.
5. I find with my SRAM setups that I don't need that much tension in the cable when clamping.

StillGoing

The SRAM double click on the rear is designed so that the bigger the push you give the lever, the more gears it will change down. It only needs a slight push to change down one sprocket.

arlowood

For any others out there with indexing issues on SRAM I can confirm that my problems have been solved.

In the event I didn't go back to the first principle procedure I outlined above but instead I used a technique gleaned from a contributor to another forum some while ago. Here is the process as described

"Shift into one of the middle cogs. Doesn't matter which one. Doesn't matter if it's a little noisy at this time.

While pedaling the bike, turn the cable adjuster counterclockwise slowly to cause the derailleur to shift on it's own to one cog larger. In other words, you're not doing anything with the shifter, just tightening the cable. Stop adjusting as soon as it shifts.

NOTE: if you can't turn the cable adjuster enough to make this happen, you'll need to loosen and re-attach the cable to the rear derailleur to take out some slack. Make sure you do this with the cable adjuster turned almost all the way in (maybe just 2-3 turns out from fully in) so that you have plenty of room to tighten/lengthen it later.

Then, moving the barrel adjuster 1/4 turn at a time the other way - clockwise - turn the adjuster clockwise until it shifts down to the "correct" cog, and keep turning it clockwise until it just shifts onto one cog smaller. Again, stop right when it shifts to that smaller cog. Count the 1/4 turns while you are doing this. From the "larger" to the "smaller" cogs it will probably come to something like 15-18 quarter turns, but that number doesn't really matter as long as you count. It's easy to count, because that barrel adjuster at the rear derailleur has detents every 1/4 turn.

Then, turn the adjuster back the other way - counter clockwise - counting your 1/4 turns and stop at 1/2 the number you counted when you went from "one cog too big" to "one cog too small". This will cause the derailleur to move back to the "correct" cog, but it will be exactly in the middle of the correct cog, not a little one side or the other. This should give you perfect shifting."

Performed as described and now everything is running perfectly with smooth shifts both ways and no noisey running in any gear.