Rear derailleur issue

S_workman

Hi all,

Firstly as it is my first post, hello .

I have recently just purchased a Giant XTC 3 (2003 I think) second hand (although I wished I hadn't as I have nearly replaced everything).

I have replaced the following:

Rear Cassette (9 Speed Shimano).
Chain (SRAM).
Rear Dérailleur (Shimano SLX).
Gear Cables (Shimano).
Chainset is next as I am getting a little slip on the middle chainring.

The Issue I'm having is adjustment of rear dérailleur which I am setting up as follows:

Top Adjustment.
low Adjustment.
Body angle Adjustment.
Secure cable (hand taught).
Barrel Adjustment.

Problem is that I need lots of barrel adjustment (tightening) to get it into low gear and then when try to change back to top gear get no where near it. There is no happy medium.

Could the shifters be worn (too little movement in each shift), or is this impossible?

Thanks for your help.


Scott.

nicklouse

the order is wrong and some parts are not needed.

read the how to on Parktools link below.

Chunkers1980

Did you replace the shifter too. Is it 9 spd?

S_workman

nicklouse: I was following the shimano instructions.I Will follow the park instructions, however the problem seems to be the range (can only get a range of 7 gears) of the derailleur not the limit adjustment.


Chunkers1980: I didn't replace the shifters and they are defo 9 speed sifters, can they wear out?

Thanks guys.

nicklouse

Ok reread what you have written.
top = H screw
low = low screw
Body angle = B screw.

so the problem is when the tension is set to pull the mech up to the BIG cog it will not drop back down to the small cog.

symptoms of poor cable routing resulting in too much friction in the cables. Or mucky/rusted cables.

Chunkers1980

Get 7?? That does not make sense.

With no cables attached does the mech move if you push it with your hand to the extremes top and bottom? If it does then it's a shifter issue.

Have you threaded the cable into the shifter correctly? It should be fully open when you do and you should be able to see right through.

pvandebe

One thing that's VERY important : Did you set min and max reaches with your chain and gear cable DEtached ?

S_workman

H and L Screws are def set correctly when the dérailleur is moved by hand as far as it will go it is in perfect allignment with the big cog. When at rest it is in perfect alignment with little cog.


Chunkers1980: I will check the shifters again, I did have both sides off the shifter when I routed the cable if thats what you mean. I think you might be right with worn sifters do you know if it is common?

Chunkers1980

I never said it might be worn - they don't tend to do that - they just completely fail IME.

Both sides off? You just unscrew the plastic cap on the back and tread in the cable. Are you sure you've not taken the shifter apart and not put it back together properly?

S_workman

I did realise that after I did them, however they are just covers and do not affect the innards. I have got another 9 speed shifter and will try that.

Thanks.

S_workman

ok defo not the shifter, doing the exact same with the other sifter.

ideas?

nicklouse

nicklouse wrote:

Ok reread what you have written.
top = H screw
low = low screw
Body angle = B screw.

so the problem is when the tension is set to pull the mech up to the BIG cog it will not drop back down to the small cog.

symptoms of poor cable routing resulting in too much friction in the cables. Or mucky/rusted cables.

S_workman

nicklouse: cables are brand new and outers are routed in the same way and the same length as old cables. I have even tried a cable length of 1 foot straight into the back of the dérailleur exact same issue.

Chunkers1980

don't you have a shadow rear mech? It's more the top on them.

What's the problemagain?

S_workman

Ok all top and bottom adjustments done, so by hand i can move the dérailleur to the big cog and its perfectly in line and at rest it is perfectly in line with small cog.

with cable attached (hand taught), if I turn the shifter to first gear it will only go to gear 3 (third from big cog). if i use the barrel adjuster at the handle bars (there is no adjuster on the dérailleur) to get it into first gear on return to gear 9 on the shifter it will stop at gear 7 and not go any further because the cable is to tight.

Also it requires 2 shifts to change 1 gear in the mid range its almost like the shifter is not providing enough movement per shift.

S_workman

also yes it is a shadow.

Chunkers1980

You don't touch the barrel adjuster - with the shifter at full release the cable needs to be fully tensioned with the chain in 11t cog so that the mech moves as soon as you apply pressure to the lever blade.

supersonic

What is the exact model of rear mech and shifter?

S_workman

Thanks all

It turns out my derailleur is only compatable with Dyna-Sys 10-speed only. Guy in the shop said it would be fine with a 9 speed. Thanks supersonic for making me question it.

nicklouse

maybe the shop guy should read this
http://www.bikeradar.com/forum/viewtopic.php?t=12733834