[Closed] Is it just me that can't set up a rear mech?

I always take all the slack out of the cable, nip it up and fine tune from there

Bent mech hanger?

Outer cable not long enough?

Rorschach +1.

Nah, It's actually a new hanger weirdly too...

I doubt it's the outer, I usually measure off the current outer, it has happened before though, I'll check.

I thought a new mech, cassette and chain + cables would sort it, keep an ear out if your around South Wales in the morning for when the chain slips on some Strava effort and I sling my knackers into the stem...

Thin oil not grease. Bent hanger. No slack in the inner cable. Make sure the outer cable runs are smooth curves.

Don't assume a hanger's straight just because it's new, if you're in the Cardiff area of S.Wales, pop into Sunset and i'll put an alignment tool on to check for you, it may well be something else, but it's worth checking.

I've never felt the need to grease/oil an inner cable.

Thought the slidy teflon liner was a no lube job
The oil/grease just attracts dirt/dust/muck

You did buy a compatable mech

Chain too long. wheel not on straight

I use sp41 so never add any more lube. Grease in SP41 is silicone based so mixing it with something else will gum it up.

Check derailliuer is the correct cage length.
Fit
Set B stop and high and low end stops manually by eye
Wind in shifter adjuster to full in and then wind it out a turn
Set cable with no slack
Put chain in middle ring of on a triple.
Try indexing one a time up and down.
Then two at a time etc. Adjust end stops if needed and tensions.

blahdee, blahdee....adjust it to the lowest gear, then drop two, then get yourself right behind the mech/cassette so you can see the angle/chainline as it meets the cassette from the mech, should be dead straight, wind the adjuster a quarter turn at a time till it looks perfect.

standing behing will also allow you to see a bent mech/hangar etc more easily.

Weirdly know one has yet described the way Shimano say that you should do it

middle ring

chain on 2nd sprocket

adjust barrel adjuster so chain rubs 3rd sprocket

back of adjuster so it just doesn't third sprocket (it runs quietly)

job done

sorry to thick to link to a pdf

google

shimano rear mech adjustment

top result is shimano guide

ps if its a shadow mech check the pivot just below where it attches to the drop out is done up propelry...

Thanks all!

Fair point on the greasing of inner, It's the commute fwiw, I only ever use the cheapo outer's on it, I'd been doing the grease thing for 15years or so (since being a kid) but can see the point re dirt attraction.

Just shortened chain, no difference, I can assure you the wheels in straight.

It's got to be an alignment issue, a year or so ago I missed set the low stop on a rear mech and managed to push the mech into the wheel on a very steep climb, ripped the whole mech / hanger to bits. It's a road bike with a replaceable hanger so I thought it'd be sorted, maybe not...Coatsey, I'm up in Pontypridd, I'll try to pop down sometime.

It's moving up and down OK, It'll just skip a gear down mid-block, I'll wind the cable out a touch, then it'll skip a gear mid block on the way up, I'm just chasing it around getting no where at the mo.

I think that the drop out the hanger bolts to is bent....

I struggled with mine for ages, took it into the lbs, turned out the plastic gromits that fit in where the cable is exposed where cheap rubbish and they needed replacing, after that all was good!

i can't do rear mechs - friction seems to be my nemesis.

just-enough-tension so that upshifts work = too-much-tension for downshifts to work.