[Closed] Help adjusting rear mech for a simpleton please

Watch this from about 4:20

I found this a handy video:

Shift the chain on to the smallest cog drop the wheel out and disconnect the gear cable, push the mech towards the wheel, does it line up with the largest cog, if not turn a limit screw a 1/4 turn, if it moves the mech then great you've found the L screw, if not then you've found the H screw, set the limit screws with the cable disconnected, reconnect cable and adjust tension to get the indexing right. oops my bad just re-read that dont drop the wheel out 🙂 it is easier if the chain is off.

Cheers !! Some progress - I now know that the bottom screw adjusts the big sprocket limit and the top one the small sprocket.

Armed with that I can now shift to the smallest cog and the chain doesn't drop in the spokes anymore.

BUT, now when I shift one gear from the smallest sprocket up it shifts two gear - and conversely, when in the biggest cog I need to shift twice for the mech to go down one gear... How do I fix that ? Is that because of cable tension ? Too much ? Not enough ?

Cable tension...or bent mech hanger..if it shifts fast small to big then cables probably to tight...it only needs small adjustments.

Too much ?

This

Thanks again - I have now been tinkering with cable tension for 45 mn but I can't get it right as depending on the tension it makes the other problem start again (the limits, which I thought I had sorted) - is that normal in itself ?

Really pissed off now as it's sunday and I shouldn't spend hours doing that - cycling is my passion but this really makes me want to do more track days instead (my other passion) as things are so much simpler there despite the massively more complex machines involved.

Any advice would help but it sounds like a shop visit - I don't trust my local shop despite it having a good rep as they normally have poor attention to fine tuning. Or maybe my expectation of my entire range of 10 gears working on a recent full Shimano XT/SLX stuff all working is too high ?

Thanks again - I have now been tinkering with cable tension for 45 mn but I can't get it right as depending on the tension it makes the other problem start again (the limits, which I though I had sorted) - is that normal in itself ?

Worthing, West Sussex

but I can't get it right as depending on the tension it makes the other problem start again (the limits, which I thought I had sorted) - is that normal in itself ?

No, limit screws are completely independent of cable tension.

Not my part of the world, so can't help with recommendation..it's important that the limit screws are set with the cable disconnected.

OK, let's start again, with the bike in a stand if possible:

Shift the shifter into the smallest sprocket.
Disconnect the cable at the mech.
Wind the shifter barrel adjuster all the way in, then two turns out.
Wind the mech H limit screw out until the upper jockey wheel is slightly outboard of the smallest sprocket, then whilst turning the cranks forward, wind it in until centred on the smallest sprocket and the chain runs smoothly.
Re-connect the cable at the mech, and whilst turning the cranks forward, shift into the second smallest sprocket.
If it doesn't shift cleanly and correctly, increase the cable tension (wind out the barrel adjuster) until it does.
Go up and down the block, but only as far as the second largest sprocket, checking the shifting is ok.
Finally, set the L limit screw by shifting to the largest sprocket and keeping the shifter pushed all the way in - the limit screw should allow the top jockey wheel to go just inboard of the largest sprocket when the shifter is all the way in, but not enough to derail the chain - this means that when the shifter is released, the mech is not sitting against the limit screw (unlike at the other end).

Cable tension at the barrel adjuster should be increased if the shifting is sluggish from smaller to larger, and vice-versa. Only adjust a quarter of a turn at a time.
On the smallest sprocket, the cable has virtually no tension so the mech position is determined by the H limit screw. At the largest sprocket, the cable is at full tension and holds the mech in position - the L limit screw is there to prevent over-shifting into the spokes.

That's the method I follow every time, and it takes a grand total of about five minutes to set up perfectly (assuming nothing is bent, cables are running free, etc)!

Thank you so much !!!!

I don't have a stand so it may take a little more time but will give it a go !!

Works just as well with the bike sat upside-down.. 🙂

I have always set the limit screws wirh cable attached. If it didnt limit properly because the cable was attached, it would be useless when you did attach it.

Well it didn't go well - if the process is 5mn, it took me 15mn to reattach the cable alone - it simply won't come back to the original place as if it had become shorter - I have checked it all the way and all is in place - but it's now all frayed at the end. I did try and align without the cable and it was running smooth but you can't tell if spot on as turning either way doesn't make a huge difference so plenty of room for error - anyway followed the steps and despite apparently being in line the sifting is even worse than when I got it worse than this morning - basically compared to now it was fine yesterday.

If that's a job that shouldn't be done without a stand, could someone please tell me.

Majorly ruined my sunday PM. Booking a track day - I love cycling but hate the faff!!!!

Yep...when you've done hundreds of them you can leave the cable connected, because you can feel when the mech is on the limit screw, when you're new to doing them its best to disconnect the cable to make sure its the limit screw and not the cable tension that limits the movement.

I tried the bike upside down and ruined my RS lock thingy plus the saddle but no big deal - it was shifting OK at one point then rode the bike and zero correlation to the way it was shifting under normal load so that didn't help sadly

don't forget to make sure cables and outers are clean and moving smoothly before starting, also use a little light lube.it is a real PITA if the cables are sticking before you start.
sometimes you can spend ages trying to sinc the gears, whilst a short ride round the garden can show that they are working ok in use

Cheers - I did clean and lubricate the cables just now but wish I hadn't as detaching the cable made a bad situation worse anyway. I was probably nearly there but nowhere near now. This all seems very medieval all this stuff tbh. Hasn't anyone invented something a bit better yet ? I am probably too old for SS!

How old is the cable? Are the end caps plastic? If the answers are old and yes, save yourself a lot of grief and get new. There's a great guide to setup on the park tools website. Unless you've clouted it, a sticky cable is likely your problem.

Caps are plastic, but as opposed to what ?
The cable is 2 years old but low mileage.
Happy to change it but no idea how to change it at the shifter end : is it hard ? On current form that probably means a new shifter...

Caps can be plastic or alloy, plastic ones can wear and bend and impede cable movement.

I'd say that regardless of mileage after 2 years it's no bad thing to replace your cable inner (which you say is now frayed anyway) and the outer to ensure that all is running smoothly.

Changing the cable is easy enough, just make sure you have clicked into the smallest cog and remove the little plastic screw from the shifter, it's located on the body between the levers. Then just push the old cable through.

What cable/ferules do you suggest ?

Problem with new cable is it will stretch and the adjustment problem/snow ball effect will start again. Isn't there an alternative solution like electronic or something?

Problem with new cable is it will stretch

Cables don't stretch.

Isn't there an alternative solution like electronic or something?

Yup. I suggest that you buy Shimano Di2

(although taking the bike to the shop to setup your gears would be several hundred pounds cheaper)

Cheers!!

Good to hear that cables don't stretch - I'll probably get the bike to a shop this week although I inherently don't trust them as they focus on symptoms rather than root cause.

What is the other adjustment to the mech ? Some sort of angle I think ?

I am wondering if this is not also due to my bizarre choice of rear mech which is compatible with 11-36 according to Madison (surely they know) but in fact is not compatible as my chain has loads of slack at one end and is super tense at the other - I wonder if that's related and/or is fixable with the other mech adjustment or with a Goat thing from the US?

It might be simple if I go straight to 11-speed and sell the hardly worn out parts.

DI2 seems to be the way to go to get rid of the seemingly archaic way gear are still being changed - should be a £50 premium in 2/3 years so might wait until then to upgrade if I can get the fing bike to work !!

Thanks all - what a faff.

metal end caps, proper cable cutters for the outer and inner ( need not be expensive ). file the outer ends flat if you're feeling diligent. cables don't stretch but stuff does 'seat'. just get yourself a decent book or something, it's really not that hard if you get the tools and take your time.

Cheers Del !! Will get myself a stand too !

Thanks for all the help everyone - changed the cable and outer for XT with the rubber boots. I couldn't see anything wrong with the old cable/outer.

By god, they must have been totally FUBAR though.

Took 2 minutes to adjust the mech and the shifting is so sharp/immediate/positive, like an entirely new tranny, which it is really...bar the cable.

I now realise that shift quality only progressively/gradually worsens over 2 years so you don't really feel it getting worse and only realise it has gone shyte when you change the cable.

£6.49 well spent as the kit comes with x2 of everything and I only have one mech!

Sorry for the grumpiness too.

I've had two contrasting experiences with setting up rear mechs: on my road bike I had problems with trying to change the cable. In the end I gave up and took it to the local bike mechanic. I hadn't got the rear wheel correctly sat in the dropouts! Doh!

Conversely fitting a mech to the fat bike was the easiest thing going, just followed the instructions: adjust limit screws, sort indexing, adjust B screw, tidy up.

Like many things, they seem complicated until you actually get in there and try it. Once you've done one or two then you get the hang (sic) of things and it's not so bad.

well done lad. 8)

Glad to hear you got it sorted without having to buy Di2!

Yeah that was a bit OTT !!!! I really can't see the point of that at that money vs £6.49 yearly... and a bit of patience!!!

Hah, you got it sorted. I was waiting for the "so i took my x9 shifter apart to fit the new cable and bits flew everywhere" 😉

It did cross my mind !!