/ Tuning rear gears

This topic has been archived, and won't accept reply postings.
EeeByGum - on 08 Apr 2013
I have replaced the rear gear cable, cassette and chain am having real problems tuning my gears. I have adjusted the upper and lower blocking screws correctly and adjusted the cable tensioner so that the derailleur is in the correct position, but no matter what I do, I am in a position where once cycling, I have to click twice up and once down to go up a gear, and twice down and once up to go down a gear. It is particularly bad with the high (smaller) gears. Some times I have to click three times before the chain jumps.

Any ideas on how I can get a click-once-gear-changes action going as it was when new about a year ago?
sleavesley on 08 Apr 2013
In reply to EeeByGum: are they shimano STI?
You tube indexing gears and you'll find a demo of how to do it
AlisonSmiles - on 08 Apr 2013
In reply to EeeByGum:

Daft question but did you replace the cassette like for like and adjust the chain length to be the same as the old. I suspect you did, in which case apologies for being patronising, and indeed I have nothing to offer ...
EeeByGum - on 08 Apr 2013
In reply to AlisonSmiles: No patronising at all. Yes I did buy like-for-like, but a good point. Have followed the advice offered by some excellent Youtube videos, but as ever with HowTo videos, they show you how to tune your gears and not how to troubleshoot particular problems encountered on the way.
sleavesley on 08 Apr 2013
In reply to EeeByGum: have you indexed them as follows
http://www.youtube.com/watch?v=SkzvfCaIbyQ

It sounds like an indexing problem.
George Fisher - on 08 Apr 2013
In reply to EeeByGum:

Worth checking the cable runs smoothly in the outer without the mech attached. Sticky cable cause shifting stickiness.

Squirt some wD40 down there followed my some light grease or chain lube.
cousin nick - on 08 Apr 2013
In reply to EeeByGum:
Again, not wishing to patronise, but have you set everything up 'by the book' (e.g. Parktool Blue Book).
I did my MTB 9-speed system a while ago, setting the upper and lower limit screws. Getting the cable tension just right can take a bit of time. Plus, with all new cables and outers/ferrules, it can take a little while to bed in. The book describes setting cable tension by adjusting the cable adjuster so that the chain just starts to rub on the next larger sprocket, then backing off till it stops. Check this on every sprocket. The detail is more than I can remember here, but it was not a quick task and needed re-doing after everything had settled in after a couple rides.
Failing that, as others have said, it may be an indexing problem, or cable friction.
Hope that helps and good luck.
N
EeeByGum - on 08 Apr 2013
In reply to cousin nick:
> (In reply to EeeByGum)
> Again, not wishing to patronise, but have you set everything up 'by the book' (e.g. Parktool Blue Book).

Hey - don't feel you are patronising. That is excellent advice and no, I don't have the book, but yes, it looks like I am going to get it! :-)

I have never really done the more intricate bike maintenance but having recently discovered how simple most of it is with the correct tools, I see no excuse to shy away any more. That said, like you say, it can take quite a bit of tinkering and experience before seemingly easy tasks can be done with accuracy and precision first time.
Horse on 08 Apr 2013
In reply to EeeByGum:

See:

http://www.parktool.com/blog/repair-help/rear-derailler-adjustments-derailleur

I find modern 9 and particularly 10 speed quite sensitive to small adjustments in tension. In fact the 10 speed MTB is a real sod.

One tip for new cables to pre-stretch before tensioning at the barrel adjuster. To do this put the cable in as normal, then cycle it through the gears by pulling on it with you hand (put a glove on) under the down tube. Do it 4 or 5 cycles and you might be surprise how slack it has become.
EeeByGum - on 08 Apr 2013
In reply to Horse: Cheers Horse - that is an excellent link. It is a 9 speed so that perhaps explains my frustration. Will print out and go over it this evening.
Rigid Raider - on 08 Apr 2013
In reply to EeeByGum:

Check that the cable is slipping easily through the plastic guide under the bottom bracket. I use maltodextrin in my drink bottle on long rides and inevitably some gets dripped on the frame, dribbles down and gums up the cables.

You replaced the cable but did you replace the outer where it curves around to the derailleur? This is where rust and crud accumulate and cause bad shifting. Treat the bike to a full set of new cable outers or at the minimum, new rear outer and you'll be astonished at what you have come to accept as standard performance.
Mr Moac on 08 Apr 2013
In reply to EeeByGum: Had a similar prob after I'd dropped mine, turned out to be loose/ damaged hanger screws.
EeeByGum - on 24 Apr 2013
In reply to EeeByGum: Cheers for all the tips folks. Got it sorted now. Turns out I had the wrong sort of chain on too. I had an SRAM chain (whatever that is) that has straight edges which impaired gear shifting on my Shimano gears. Have swapped it out for a chain with rounded edges and changing is much smoother now.

It is all way above my head, but all is well so I can remain blissfully ignorant.
In reply to EeeByGum: Interesting. Just because a chain is made by SRAM though, shouldn't mean it won't work if they say it's Shimano compatible ("Hyperglide" is the system name I think). At least I think SRAM make chains that should be compatible.

I'm having similar probs with the front mech on my CX bike. Annoying, and if you decide its the cables, buy new ones, set them all up, etc. you know you're going to have to fiddle more in a couple of weeks once they've stretched a bit!
Horse on 24 Apr 2013
In reply to TobyA:

You can avoid the worst of that fiddling by stretching the cables during installation. Set everything up so it works. Put the chain on the small ring. Then pull the cable under the down tube to shift to the big ring, do this several times (H&S warning, wear a glove). Now take out the cable slack and fine tune the set up. Any additional future fiddling can be done from the barrel adjuster on shifter itself.
captain paranoia - on 24 Apr 2013
In reply to Horse:

It's odd; I've never suffered derailleur cable stretch on index shifters. Yet...

I did once have the shifters go dry and stop indexing (LX), but a quick squirt of grease restored order.
Timmd on 25 Apr 2013
In reply to EeeByGum:

http://www.google.co.uk/#hl=en&gs_rn=11&gs_ri=psy-ab&cp=11&gs_id=16&xhr=t&q=...

For mountain biking applications I find friction thumbshifters good, if i'm out on a ride and happen to break a rear gear cable, or my rear mech hanger get knocked out of line by a rock, it's much less faff and hassle than having indexed gears.

With practice you can shift standing up too, which some don't think is possible. Not a 'do it like this' post, more of an 'here's something different to indexed for mtbing' post. (:-))
Ricardo - on 26 Apr 2013
In reply to George Fisher: someone told me u shouldn't use wd40 on cables as it removes the coating on them Teflon maybe and makes them worse in long run. Oil is OK tho. No idea if this is true or not
EeeByGum - on 26 Apr 2013
In reply to Timmd:

> For mountain biking applications I find friction thumbshifters good, if i'm out on a ride and happen to break a rear gear cable, or my rear mech hanger get knocked out of line by a rock, it's much less faff and hassle than having indexed gears.

Gosh - I had those back in the 90's! I am on a hybrid commuter so not too fussed about changing my gear shifters.
EeeByGum - on 26 Apr 2013
In reply to TobyA:
> (In reply to EeeByGum) Interesting. Just because a chain is made by SRAM though, shouldn't mean it won't work if they say it's Shimano compatible ("Hyperglide" is the system name I think). At least I think SRAM make chains that should be compatible.

I am not disagreeing with you Toby, just repeating the propaganda given to me at the bike shop. It sounds plausible and the new chain definitely changes more smoothly. Oh - and Hyperglide is the word I was looking for - thanks!
ads.ukclimbing.com
Timmd on 26 Apr 2013
In reply to EeeByGum:
> (In reply to Timmd)
>
> [...]
>
> Gosh - I had those back in the 90's! I am on a hybrid commuter so not too fussed about changing my gear shifters.

Fair enough. I can index gears, and have done with my parents bikes, but halfway through i'll start thinking about other things I could be doing, and how much nicer it'd be not to need to, and can lose patiance with them.

If I took the time to keep my cables well lubed and things like that it'd help, but something about the fiddling with them drives me nuts. It's one of my quirks I suppose.
Orgsm on 26 Apr 2013
In reply to EeeByGum:

Sounds like not enough tension in the cable, or the cable isn't routed correctly into the bolt that clamps it. Try the barrel adjuster first for tension, and if still not right, look at cable outing. Also check the b adjuster screw which faces out awkward a from the hanger. Adjust till jockey wheels as close as possible to cassette teeth, then back off a 1/8 turn or so.

Good luck.
Mostro - on 26 Apr 2013
In reply to EeeByGum:

I had the same problem as Mr Moac. My bike wasn't changing smoothly for a few months and I couldn't suss it out. Eventually I removed the rear mech hangar, put it on the table and voila - it wasn't flat anymore. Must have given it a knock somewhere. The new hangar made an instant and welcome difference to gear changing. They're designed to bend and bend they do ! I always carry a spare in my bag and I'm currently on the fifth in four years. 15 well spent.
Bob_the_Builder - on 26 Apr 2013
In reply to Mostro: The rear derailleur cage often gets bent too. I normally straighten them out (both cage and hanger) with a vice or handy hammer. =] Designed to bend, but also therefore quite easy to bend back. Admittedly you'll never get the hanger quite perfect again. But you can normally get it good enough that everything shifts smoothly.

Another slightly embarrassing one I've had (as someone previously employed as a bike mechanic) is getting so much muck in my guide pulleys that my chain skipped. A simple clean sorted that one out.

This topic has been archived, and won't accept reply postings.