What are the symptoms are of running a 1:1 shifter with a 2:1 derailleur? My utter inability to dial in a unidentified (beat up) SRAM shifter with an XT rear mech makes me think the shifter is a 1:1 model (hanger is straight)

symptoms are: it don’t work

Um, yeah, but I wanted to make sure I’m not going insane or there’s some other problem… I cannot get BOTH the full range on the cassette and one-cog-at-a-time shifting, it’s either not the full range and reliable shifting for 4-5 gears, or full range and reliably skipping at least three cogs through the range.

The SRAM shifters with names rather than series numbers are more likely to be Shimano compatible. So X5, X9, X0 won’t work. Rocket, Attack and some Gripshift should.

yeah… but my problem is I do not know exactly what the shifter is… could be an attack or could be an X5. That’s why I’m trying to identify it by identifying the adjustment problems I’m having (it’s on a beat-up bike a I recently bought for cheap).

Solution would be to get a new rear mech or new shifter, but I wanna be sure I’m not doing something dumb with the current gear before plunking down more money.

sram rocket or attack will work with shimano

Temporarily Swap it for a shimano shifter and re-test? or an X7, X9 or x9 mech if there’s one available.

There is always the possibility the shifter is just knackered if it’s beat up enough to be unidentifiable.

Google the original spec of the bike?

yeah, I’m gonna pick up a used SRAM mech to try out… the shifter seems fine and the indexing seems crisp enough with a new cable. I suspect it’s an X5 or some other incompatible shifter. The rear mech is old and could do with replacing anyway methinks

it’s either not the full range and reliable shifting for 4-5 gears, or full range and reliably skipping at least three cogs through the range

If the shifter is incompatible you’ll shift 2 cogs for every click. If it’s compatible you’ll get one for every click. This full range business is misleading you. If the shifts aren’t perfect, you’ve either got to adjust cable tension or accept that something else is wrong

SUre it’s not a new 10sp XT ?
CLean, new cable and outer ?
Cable clamped correctly at mech ?
Outer not oddly routed or too short ?
Hanger definitely not bent, or just “looks straight” ?
Mech and hanger properly fixed to frame ?

Thanks… I wondered if the two cogs per click might be the symptom, and that is fundamentally what’s happening I think. I adjust like crazy to get the first 3-4 cogs working right, but then it’s 2 cogs per click and I’ve already come to the end of the barrel adjuster travel, so I’ve probably simply adjusted to mitigate the incompatibility for half the range.

The other symptom is that clamping the cable as normal on the smallest cog result in the cable getting too tight to get into the largest cog. Letting enough cable out at the clamp to reach the largest cog means it’s sloppy once changed down to the smallest cog. So overall there’s too much cable travel for the derailleur, which also suggests it’s a 1:1 shifter.

Other than that, it’s a brand new cable and outer and the outer is cut fine. Certainly not a 10sp XT mech (it’s far too old for that) and everything else is set up OK.