Bicycle Mechanics - SRAM Chain Skip & Slip,

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View Full Version : SRAM Chain Skip & Slip,


roccobike
07-02-05, 06:52 PM
I have an old, but excellent condition Nishiki Ariel I purchased used. I had the bike checked out at the local bike shop who stated the chain and cassette were badly in need of a cleaning, but still in good condition. For reference in this discussion, the rear unit is a 7-speed Shimano Deore, all original and working fine. The bike is of 1989 vintage.
I needed a chain for another bike, so I decided to buy a new chain for the Nishiki. The bike shop sold me a SRAM PC-68 (for 8-speeds, but this should not be a problem). They recommended the SRAM and I like the SRAM with the powerlink. It is THEE cool chain to use in this area.
I removed and cleaned the cassette, re-installed it and installed the SRAM chain after matching the length to the old chain and lubricating it with Finish-Line Teflon Plus. I noticed an immediate improvement in shifting, but that was the last good news I had. As soon as I shifted to the top end gears and applied some power, the chain (or cassette) started skipping (or slipping). This is only a momentary skip or slip, like a one link skip, but it is a major concern. The higher the gear, the worse the problem. This only occurs when using the top three gears. I feared the worst, I might have damanged the cassette.
I cleaned the old chain, lubed it with teflon-plus, and installed it. The skipping stopped, completely stopped.
OK, does anyone have any idea what's happening? Do I need to adjust the deraileur with the new chain? Is the SRAM not compatible with the old Shimano cassettes? I did not remove the thin layer of packing grease from the new SRAM chain, is that a possible problem? Has any one else experienced this. Thanks for taking time to read this and respond.
Roccobike


neil0502
07-02-05, 10:03 PM
Odds are pretty good that the cassette /is/ worn out, primarily in the gears where you're experiencing skipping.

As the chain wears excessively, the cassette wears /with it/. IOW: it won't skip with that chain, but /will/ skip with a new one.

These links (no pun intended) may help:

http://www.execulink.com/~dtierney/wmc/SRAM/chains2.htm#Chain%20wear

http://www.sheldonbrown.com/chains.html

Meanwhile . . . you need a new cassette. Look /closely/ at the teeth on the cogs where you're experiencing the slipping. I bet you'll see the wear....

Doctor Morbius
07-03-05, 10:11 PM
I see Neil has posted the Sheldon Brown link that applies to your situation. However, it would probably be a good idea to read over the other articles as well just so as an FYI.


Here are the definitive words on chain maintenance and when to replace a chain. This should really be a sticky due to so many chain questions.

Sheldon Brown:
http://sheldonbrown.com/chains.html

Lennard Zinn - Everything you ever wanted to know about dirty chains:
http://www.velonews.com/tech/report/articles/5610.0.html
Very good article! Suggests replacing at 1/16" stretch.

Lennard Zinn - Chain wear:
http://www.velonews.com/tech/report/articles/5457.0.html
Suggests replacing at 1,500 miles and before 1/8" stretch.

Park Tool - CC-3 Chain Checker:
http://www.parktool.com/tools/CC_3.shtml
The CC-3 is a "Go, No-Go" gauge designed to accurately indicate when a chain reaches 0.75% and 1% wear.

CC-3 here for $10:
http://www.nashbar.com/profile.cfm?category=99&subcategory=1234&brand=&sku=11164&storetype=&estoreid=&pagename=