XTR Shifting help

I've got an Amp b-4 that I've really never gotten to shift well. Originally
I was sporting a sram 8 speed 9.0 rear derailleur and shifters with a
Truvativ Stylo Crankset and BB, and XTR cassette. It was shifting OK, but
should have been better. When I broke the derailleur, I put on an XTR rear
derailleur and a set of M910 XTR shifter/brake levers. I was using a sram
PC68 chain with each setup. The shifting actually got worse (braking was
great), so I put on a Shimano IG90 chain,(per Truvativ instruction) and then
it was worse yet.
I believe my chainline is correct, but I could be wrong. I've spent hours
trying to adjust it, and I will not give up until I get it right. I might
add that I've been building and repairing my own bikes for some time, and
pride myself on the fact that none of them have ever been in a bike shop
for repairs. I'm too stubborn to take it in, and to be honest, I am at odds
with my LBS.
If there's something I'm forgetting, or something I am not aware of
regarding compatibility, perhaps that could be addressed here.
I can get it to shift up and down the cassette rather well; it just skips a
gear each way. It seems to me that the shifter and derailleur aren't in
sync. Just to make sure I put a Sram "plasma" shifter on temporarily, and
it really didn't shift any better. It looks to me as if I either have a
chainline problem, or compatibility issue. The derailleur is aligned pretty
well, so that isn't the problem. Frankly, this has me stumped. Any advice
or suggestions would be greatly appreciated. TIA, Greg

wrote:

I've got an Amp b-4 that I've really never gotten to shift well. Originally
I was sporting a sram 8 speed 9.0 rear derailleur and shifters with a
Truvativ Stylo Crankset and BB, and XTR cassette. It was shifting OK, but
should have been better. When I broke the derailleur, I put on an XTR rear
derailleur and a set of M910 XTR shifter/brake levers. I was using a sram
PC68 chain with each setup. The shifting actually got worse (braking was
great), so I put on a Shimano IG90 chain,(per Truvativ instruction) and then
it was worse yet.
I believe my chainline is correct, but I could be wrong. I've spent hours
trying to adjust it, and I will not give up until I get it right. I might
add that I've been building and repairing my own bikes for some time, and
pride myself on the fact that none of them have ever been in a bike shop
for repairs. I'm too stubborn to take it in, and to be honest, I am at odds
with my LBS.
If there's something I'm forgetting, or something I am not aware of
regarding compatibility, perhaps that could be addressed here.
I can get it to shift up and down the cassette rather well; it just skips a
gear each way. It seems to me that the shifter and derailleur aren't in
sync. Just to make sure I put a Sram "plasma" shifter on temporarily, and
it really didn't shift any better. It looks to me as if I either have a
chainline problem, or compatibility issue. The derailleur is aligned pretty
well, so that isn't the problem. Frankly, this has me stumped. Any advice
or suggestions would be greatly appreciated. TIA, Greg

Several things come to mind...

1. You have the cable attached to the wrong side of the clamping bolt on
the DR. It makes a difference.

2. The DR is not parallel to the wheel; i.e., the DR hanger is bent.
Your LBS will have a tool to check and bend it back in needed. You can
usually see it if it's bad enough for it to shift the way that you're
describing -- the DR tension arm should be parallel to the plane of the
wheel -- just stand back from the bike and look at it.

3. The shifting cable is not moving freely. This is a common problem
with 9 speeds and why I personally have to use teflon coated cable.
Plain steel just won't work reliably on my bike. Try replacing the
cable and housings.

David

Dave:
Thanks so much for your advice. I did indeed have the cable on the wrong
side of the derailleur clamping bolt. I switched it around, and voila!,
great shifting again. I feel a bit silly for not noticing in the first
place as the angle was bad. Anyway, thank you........ Greg