Tuning tips?
 

I'm trying to tune my mtb's 9 speed rear derailleur, but I'm having some problems.

The chain will get to all of the gears, but it is not tightening or loosening quick enough. When I shift up, for example, from 1, it will not change on the first click. then it will shift up lagging one behind, until it gets to the 3rd gear from the top, at which point it will jump the 2nd last gear and go straight to the last.

As well, sometimes it will shift properly, right up until the last gear, where i will have to mash on the pedals before it changes.

I cleaned and re-lubed the gears, but this yielded no change, nor has changing the front ring.

Can anyone give me any tuning tips? I'm using a Shimano XT from last year, so there should be no problem in regards to the quality of the derailleur.

It sounds like a stretched shifter cable, which is a normal part of use. try simply twisting your barrel adjuster. Some bikes have them by the shift levers, some have barrel adjusters down by the derailleur, and some have both. You will want to effectively shorten the cable, but to do so you must effectively lengthen your cable housing. If your barrel adjuster gets maxed out, then you'll have to put the RD in the smallest cog, set then High gear limit screw so it holds the RD over that cog, then loosen the bolt that holds your cable onto the deraileur, and then pull it tight, and then tighten the bolt, and then back the limit screw off a half turn.

Hope that helps.

good luck

Yea, thats what I've been doing, it just seems to be some precision work to get it to the right tension. I've been using the barrel adjuster down by the derailleur, but that things bullocks. I'll definitely look into a barrel adjuster by my shifters, though, i totally forgot such a thing could exist. I'll check it.

Also, forgot that you can change the derailleur alignment. But where would i find that screw? I don't want to tweak around with the wrong screws

You need to redo the adjustment starting from step #1:
http://www.parktool.com/repair/readhowto.asp?id=64

Other factors may come into play as well - worn chain/cogs/chainrings etc.

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[QUOTE
Also, forgot that you can change the derailleur alignment. But where would i find that screw? I don't want to tweak around with the wrong screws[/QUOTE]

Here's a quick and dirty picture. you may have a hex nut rather than an allen head nut for the cable clamping screw, but it does the same thing. and you can't really see the set screws but they should be located about where the line points in the picture.

Also, check to make sure your deraileur is in allighment, ie, that your hanger is still straight. Do your pulleys track fairly true to the direction of the chain (they should)? And are the pulleys angled inward or outward (they shouldn't be)?

i've found out that a kink in the derailleur cable can cause some shifting woes as well. make sure the cable is straight, that your cable housing ends are cleanly cut and capped.

also lube the cable and housing as the cable may be gummed up and not "relax" when you move the shifter

yep, and what bikemedic said too.

and speaking of housing, make sure you're using the right type. SIS is the way to go with a 9 speed drive train...

Okay, so this is how it is now. I've tweaked around with the limit screws, and the tension screw, and now i have this problem. When i am on the lowest gear (biggest sprocket), and i shift to the second gear, it will not shift. i have to shift twice before it will get on the next sprocket. from there, the gear will generally shift smoothly , until around the last gears, where the ring will jump over a gear to get to where the chain should be. the derailleur seems to be in good shape. Should I keep tweaking the limit screws, or is there something else that will fix this?
And no, it doesn't look like the cable housing is gummed up, but i'll check that once we have the water outside running again (its still half-winter up here)

Are you following the park guide? Your symptoms sound like a limit adjustment issue to me.

I have been, but I'm new to working with these limit screws. The chain gets in the first and last sprocket no problem, it just has a problem getting to the sprocket right after it. That means i probably have to shorten my limits, right?

That's 1/2 of the answer. I always try that first because most of the time that'll do it.

If you're not getting good results using just that half here's the rest:
1. Shifter and number of cogs on the cassette have to match. (Easy to check.)
2. Fresh, clean shift cables and housings. (If in doubt, throw them out.)
3. Derailleur hanger alignment. (On a 9-speed cassette this takes a special tool. Don't skip over it because it's a very common problem.)

ps: Limit screws are almost never the issue.

http://www.youtube.com/watch?v=SkzvfCaIbyQ

honestly a great video about adjusting rear derailleurs. hope it helps!

I had this exact problem with a mountain bike. Seven speed Suntour indexed gears. Changing down was fine, each click moved onto the next biggest sprocket. Changing up, as you say, it lagged one step behind then changed two at once.

In my case it was resolved by renewing the outer cable (housing). The old cable setup must have just had too much friction for the return spring on the mech to pull the cable through. New cable and housing made the controls lighter as well.

Tony S