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I can't seem to get my rear mech to shift properly. If I click up through all the gears (2x9) then a couple of clicks don't do anything, so I can't get into the biggest two sprockets.
This all started (I think) after the rear mech decided to try to eat a stick.
- XT 9 speed shadow rear mech (new, replaced the old one after the incident with the stick)
- SLX 9 speed shifter.
- Replaced cables and inners.
- Taken the bike to the LBS to straighten the (steel) frame with their frame gauge thingummy. Made no difference.
- Tried twiddling the barrel adjuster. I can use this to choose any 7 consecutive gears I want....
- I can select all the gears if I push the shifter by hand - it's not the limit screws.
- New chain and cassette (the old ones were toast anyway)
The inner cable is attached onto the little groove on the rear mech, I assume that's the right place.
Is it possible to actually bend the entire frame out of shape? What else am I missing?
It's a 26" frame; I don't get this problem at all on my single speed 29er 🙁
Thanks.
I'd be still looking at the hanger, though the shifter is also a slim possibility. The fact that the problem started after damage would suggest that either the frame/hanger is not right or you've not installed all the new stuff properly. Start from scratch (again?) with a set-up.
cable tension
Is the dropout straight?
Failing that start again with setting them up.
I use the park tools method with success.
Sounds like the shifter was in 7th - 8th gear when tension was setup!
State the bleedin' obvious mode.
Check the cassette is on correctly. Chain off. Wheel in the dropouts correctly and centred in the frame. With the cable detached from the mech check the limit screws by hand. Push the mech by hand to the highest cassette sprocket. Make sure the shifter is in the "lowest gear", so the cable is released. Check the outers are seated in the ferrules and the shifter and rear mech. Again check the routing of the inner cable on the mech. Pull with a pair pliers and tighten the cable clamp bolt.
It should index on to the next sprocket OK. If not add enough tension with the barrel adjust so it does. Then release the shifter so it drops "down" to the smallest sprocket. You may need to fine adjust so it goes up and down one sprocket at a time OK.
If it won't shift up and down the whole cassette after that then the mech hanger is bent. Which in short was what I was going to say in the first place. A tiny amount out at the hanger seems to exaggerate problems at the larger sprockets on the cassette.
One more thing.
If it's a new mech, check the B Screw adjustment / alignment of the jockey wheel to the largest cassette sprocket.
5-6mm gap between the teeth without the chain on.
Is the mech bent?
I don't think the mech is bent. I think the hanger is the problem. One last chance at the lbs. Then a new frame or just mtfu on the steep hills!
I had this problem and lived with it until I took the bike to the lbs. I'd put the cable on the wrong side of the screw on the mech. Worth checking
opposite problem here. Can't get down to smallest cog (well I can but you can tell its thinking about jumping every few revelutions). Cable isn't attached, and limit screw wound right out)
I'm going to say its a bent rear mech. Easy to straighten?
Fixed!
Took it to the LBS.
Wrong kind of lever arm on the rear mech 😯
It was a mech I'd bought from this very shop many months ago, and it had never indexed properly - but I'd assumed either the frame was bent (as above) or I had just fitted it wrong!
After a lot of investigation including help from the Shimano rep, the problem was discovered! They've replaced the mech and it's all now fine!
Now I just need some dry dusty sweet flowing singletrack....
Was it a 10 speed mech in a 9 speed box? Or assembled from the wrong parts?
I think it was actually assembled from the wrong parts!