on the cross bike which i’m commuting on, Sram Rival 1×11

at some point, in every one of my last 6 rides, my bike decides it doesn’t want to use the smallest cog, and aligns itself perfectly to the 2nd smallest, therefore giving me a 1×10 setup, all still working spot on apart from the now redundant 11T cog… I get home, loosen the derailleur cable reset the gears again, check in the stand, go for a little test ride round the estate, and we’re back to using all 11 cogs… rinse and repeat…

i may have been guilty of being rather foul mouthed towards my bike this morning 😳 8)

what is happening!?!?!

Maybe you’re not quite allowing enough tolerance to drop into the smallest.
Try being a tiny bit more generous with the limit screw?

ok, worth a shout… will give it a bash…

gungy cables with a bit of dirt could do this also – maybe replace inner and outer if limit screws don’t sort

With it being 1×11, could it be that the chainline needs moved out a wee bit?

I think the b screw could do with a tweak. I’d try that first if it were my bike.

fairly new cables maybe 200 miles old (if that)… and moving the chain line.. erm, without wishing to sound thick, how does one do that? 😳

SRAM mechs have an odd shape, the chain length needs to be adjusted such that the mech wont foul itself in second smallest cog, preventing it getting onto the smallest. Look at the mech in the smallest cog. You will (probably) see that the round cable routing ‘wheel’ that takes the cable from the outer round to the bolt is touching the mech cage between the two jockey wheels, or perhaps touches it when shifting. You will also see that the mech cage is shaped such that as you adjust the b tension screw, the cable guide will have a little cut out area it can sit in to ensure its not hitting the mech when you go from 10 > 11. You might need to adjust just the b screw, or you may find that the chain is the wrong length altogether. SRAM mechs tend to want to run long chains, with the jockey wheels pretty much horizontally in line with each other in 11.

This is all based on my experience with other SRAM 11 groups, but I bet Rival is the same.

Sorry I was thinking threaded BB and moving a spacer,but it’s probably a pushfit?

yes pressfit BB, I’ll look at the mech etc a bit more closely…. and that mintsauce is somewhat reminiscent of my commute 😆