Hi guys,
my bike is fitted with the SRAM Apex 1 XPLR 1×12 and I'm having problems adjusting it 100%.
SRAM specifies 13mm for the chain gap, but when I set this, the shifting no longer works.
To be more precise, the 11th gear, i.e. the second smallest sprocket, is causing problems.
If I turn the derailleur barrel adjuster clockwise so that the gears shift nicely from the lowest gear to the highest and the chain arrives on the 11th cog, it always hits the teeth of the 12th cog. The two teeth of the shift gate in particular cause problems. The chain literally pulls itself up on the teeth and then jumps back onto the cog.
If I turn the derailleur barrel more in the direction of the rim, the chain moves further away from the 12th cog.
The bumping and clattering stops and the chain runs smoothly on the cog.
The problem, however, is that the gears no longer shift up properly. From first gear down to tenth gear it's no problem, but then in 11th gear the chain doesn't jump down. If I shift again, it logically skips 11th and jumps straight to 12th gear
I'm slowly running out of ideas as to what the problem could be.
Only reducing the chain gap from 13mm to 7-8mm has brought some relief here, but that can't be the solution if SRAM specifies 13mm then set 7mm. There are also Youtube videos that show that it works with the 13mm.
The rear derailleur has already been replaced and the derailleur hanger is aligned.
Does anyone have any idea what else it could be?
I have also made a Video of my Problem
by chri0tian
9 Comments
Are you talking about an XPLR group with a 10-44 or 11-44 cassette? If yes, 7-8mm is the correct distance between the largest cog and upper pulley.
Is your derailluer hanger straight?
Hanger bent
I wonder if something is wrong with SRAM’s documentation here, because [the b gap for the electronic xplr derailleurs is 7-8mm](https://support.sram.com/hc/en-us/articles/6042144738075-What-is-the-chain-gap-adjustment-for-the-XPLR-rear-derailleur-with-a-10-44T-cassette). 13mm is huge. If it works best like that I say run it. Another thing I’d check is that your chain line is correct.
You may also want to ask the guys at rbikewrench
when i had issues like this and was chasing myself in circles it was a chain worn waaaay out past its lifetime.
also the shifter cable could just be stretched/worn out/housing cruddes up. an LBS could diagnose this and repair it (or at least give you the parts list to repair if you pay them for the diagnosis)
OP figure this out yet? Definitely bring the b-gap down. I use the Force 12sp AXS with a road set up and a gravel set up. I’m constantly changing the gap for each set up, I know for sure it’s less than 13mm. I’ll measure in the morning if you don’t have an answer.
Definitely loosen the cable pinch and slide the housing ends off at each break, including at the lever, if applicable. If any of those housing ends have the wires poking out, trim them flush.
Check limiter screws (better both ways).
Set the lowest possible b-gap on the biggest sprocket.
Use barrel adjuster very carefully.
Parktool has the best ever derailleur setup video.