KMC chain
 

My Specialized Rockhopper basic has a KMC narrow chain marked with a "Z". The rear derailleur is a Shimano, as is the front. Neither is marked SIS. I think they are the Acera line. The shifting is quite sloppy. Even on the middle of the 7 cogs it is quite hard to do a front shift. According to my chain gauge I will need to replace the chain soon. Would a Sram chain be appropriate (I like the idea of the power link)? Will a new chain help the adjustment on the shifting?

A SRAM chain will be fine, my friend has a SRAM chain and the PowerLink is coolio. Make sure it is a 7/8 speed not a 9 speed.
Also, if the shifting is sloppy you may need the shifters adjusted, so you may want to have your LBS guys(or gals) take a look at it.

As regards to the "sloppyness" and difficulty of shifting, if you have very many miles on your bike, the derailleur pivots may be be worn causing the problems. To test for bad pivots, move your cages form side to side with your fingers. If there is movement more than a millimeter or two on the front and 2 to 3 mm on the rear you may need to replace you derailleurs, (compare to new ones). Shimano derailleurs, especailly the inexpensive models, are notorious for wearing out and getting sloppy at an early age. Check your pulley wheels as well, by comparing to new ones if they're much different they should be replaced. If is also possible you may have bent your rear derailleur hanger, (very, easily done). Your rear cage and pulley wheels should be parallel to, ( the planes of) your cogs.

Ride With Less Effort
Pat

Jean, I had to replace the stock chain on my Giant after the original fell apart after 500 miles, and found a mid-range SRAM chain made rear shifting better , but it didn't have much effect on front shifting. I upgraded the front derailleur to the basic Shimano Deore multi-fit model (about £16 UK) which noticeably improved front shifting, the real difference though, was upgrading the SRAM Gripshift 3 shifter for the SRAM Rocket (equivalant of SRAM 9 ESP but for Shimano Mech's), it wasn't a cheap upgrade (£25) but it really made a difference (when I finally got the front derailleur set up right :) ). If you're one of these strange people who can't see theadvantages of Gripshift over the Shimano Shifters (and there's a worrying amount of the about ;) ) I'd try upgrading the shifter to a better Shimano shifter.

One other thought what are the cables like? They might want lubing or replacing.

Richard

This Rockhopper is practically new, something like 400 to 500 miles. The cables are fine. I bought this bike to be my winter wet bike so it is ridden in less than desireable conditions, but I'm pretty diligent about cleaning my bikes' chains. Daily in the winter. Neither cage seems particularly loose, and everything looks lined up. However, the chain is almost to 1% on my Park chain tool, which seems like an awful lot in this amount of riding.

Maybe you've already thought of this but couldn't it just be the normal 'break in' wear and tear of the cable housings? This is normal after a month or so. A few turns of the adjusting barrel at the front shifter and rear shifter and/or derailleur would fix this.

Jean, if Specialized use the same poor quality of chain , Giant used on my bike, 500 miles is about right. fortunately the bike shop upgraded it to an SRAM free of charge after it started breaking on a regular basis.

I'd take the bike into the shop and see if they'll replace the chain and check derailleur set up at the same time.

Richard

Hopefully, I have the answer to my problem. As last night was the bearing, brake, & drivetrain night of my bike repair class, I took above bike with me. Yes, the chain was just short of 1%, so it now has a Sachs. The cables were fine, and the adjustment seemed OK. It turned out to be a very subtle rotational misalignment of the front derailleur. The classes (Park Tool School) are great. There were only 6 signed up. My benchmate had to repack his front wheel bearings, someone else needed a new bottom bracket, and several cables and brake shoes got replaced. There were 2 mechanics helping everyone through their basic adjustments and repairing the problems they discovered. They also offered to help if things didn't seem right in the next week. The manual is also very good. I give it a 4/5 star rating, and I will certainly make a stop at that shop the next time I shop for bikes or supplies, even if it is 30 miles from me.

Glad you're problem's sorted. Sound's like a good class, I wish there was something similar in my neck of the woods.

Richard