Bicycle Mechanics - shifting troubles with 9-speed cassettes?

I've recently built up two bikes with 9 speed cassettes. (Previously I only had 7.) One is a Surly LHT with a Cyclotouriste cassette from Harris Cyclery. The other is a hardtail Rockhopper with an 11-34 cassette - I think it's a Deore. Both have Shimano rear derailleurs. One is an XT and the other a Deore.

I know how to use the barrel adjuster for fine-tuning. The 9 speeds seem much more persnickety than my old 7s. I have to get the adjustment exactly right for the shifting to be smooth over all 9 gears.

Both bikes have a similar problem, which leads me to think that maybe there's another adjustment I don't know about. On both of them, the problematic gear is the 8th largest - the one outside of the lowest. When I use that gear there seems to be some "chain slippage" - where the pedals briefly lose load and spin freely. When I try to adjust for this using the barrel adjuster, it doesn't really work, and eventually throws everything else off.

Both of the rear derailleurs were installed directly out of the box. I know there are a couple other adjustment screws (besides the two limit adjusters.) Is there some other tuneup I need to do to get all 9 gears working smoothly?

Thanks in advance!

1. What are you using for shifters? You need 9-speed shifters and, since you're using Shimano derailleurs, you need Shimano or Shimano compatable shifters.

2. Have you had the derailleur hanger alignment checked? The more rear cogs you have, the more finicky your derailleur will be regarding hanger alignment.

I agree with Retro Grouch. Have the hanger alignment checked.

How old are the cables and cable housings?

The shifters on the Surly are Shimano Bar-ends. The ones on the mountain bike are Deore combination shifters/brake levers.

The cables and housings are all brand new.

How do you check your derailleur hanger alignment? If it's misaligned, how do you fix it? Do you have to bend something, or is there some sort of adjustment screw.

Maybe this is obvious, but are you using 9-speed chains on both bikes? Are they relatively new?

How do you check your derailleur hanger alignment? If it's misaligned, how do you fix it? Do you have to bend something, or is there some sort of adjustment screw.

Bike shops have a tool that gauges derailleur hanger alignment and also, if necessary, bends it back into line.

What chain connector are you using, BigBlue?

Check the cable to derailleur connection. If the cable is on the wrong side of the screw it can cause shifting problems.

Al

While you are looking at everything, I'd check the chain length: and easy test is no longer than needed for big-big :)

What chain connector are you using, BigBlue?

The chain on the touring bike is SRAM. I used the connecting link that came with it. The chain on the Rockhopper is Shimano. I pressed the pin in with my chain tool.

While you are looking at everything, I'd check the chain length: and easy test is no longer than needed for big-big :)

I used the method described on the Park website. I put the chain on big-big (bypassing the derailleur) and added a link or two of length until I got to the next outside-inside link connection. I think the method described on Sheldon's site is pretty much the same.