The bloody Rear mech just wont index.
Tried new cables (inner and outer)
tried New hanger
tried 2 different mechs
Whatever I try I get a horrible grinding on the smallest cog (despite limits screw being adjusted) and whilst it shifts up and down brilliantly in the biggest 4 cogs, around the middle it starts either not change up or down dependent on how i adjust the cable tension. No matter how much I try I can't appear to get the balance with the cable tension to ensure it goes up and down the whole cassette smoothly
Please help me before I have a temper tantrum and smash something.
Should mention I normally find rear mechs easy to fix, but this one is causing me a real headache.
It's probably the B screw. Nobody understand the B screw. I always just infinite monkey it- adjust it enough times with your eyes closed and sooner or later it'll be right
You haven't mentioned how old the rest of the drive train is. Why did you start adjusting it in the first place? Is the chain length correct? Having said all that.....This is almost certainly your b tension screw. Probably needs screwing in a few turns.
Or you're starting off with your cable tension to tight from the off! Undo the cable from the mech with it in top gear. Wind the barrel adjuster on the shifter all the way in....then unwind it by a full turn. Reattach the cable to the mech...do not pull it taught, it only needs to be pulled very gently so there is no dang lining slack. Now try your gears.....if there's a little reluctance to move from 10th to 9th on the cassette, wind quarter of a turn on the shifter adjuster at a time until it downshifts fine.....in my experience unless your b screw has punched its way through the mech and this can happen even through an aluminium mech it's more often than not too much cable tension applied on initial connection.
the drive train is old, but still got plenty of life in it. I would have thought worn parts would lead to skipping rather than indexing issues?
Will try the b screw. Plus reattach the cable
Plus reattach the cable
You're not going to get good shifting without it 😉
Indexing on only half the cassette I'd normally put down to a bent hanger, but you've changed that. Is the joint between the hanger and the frame clean or is there something stopping it from sitting square? Is the frame itself square?
northwinds approach of closing eyes and randomly twirling the bscrew appears to have given me a full range of gears. Its not exactly chrisp shifting, but at least it works.
Still a grinding from the small cog however...
grrrr
While we are at it why does my XT front mech hit the chain in the middle ring when in small cog or the granny ring? It doesn't hit both but one or the other.
Grinding on the smallest cog means something is set up wrong somewhere, and it all starts from getting the smallest one set up right before moving on to big and then indexing so you need to get that set up right. Is it from the mech being too close (B screw) or limit screw, or chainline from small ring if you are using 3 chainrings?
Is the mech new? If the top jockey wheel has wear or play in it the indexing will go to pot, also if there is general slop in the mech from age it isn't going to be great. Worn parts generally aren't great to work with, if you take it to a bike shop they'd probably suggest buying new parts. Also are you using the same speed cassette, chain and shifter (I've done this wrong before!)
zippykona - Member
While we are at it why does my XT front mech hit the chain in the middle ring when in small cog or the granny ring? It doesn't hit both but one or the other.
POSTED 37 MINUTES AGO # REPORT-POST
Eh? 😕
What are the shifters, mech and cassette?