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#1
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A couple of SRAM chain "chain stretch" questions
Hi all:
I've got a Park Tool CC-3 chain checker. It's one of those "go/no go" type checkers with one side registering .75% chain stretch and the other registering 1.00% stretch. (I know chains don't "stretch" per se but I'll use the phrase for convenience.) I run SRAM PC89R chains that use a "Powerlink" connector as a sort of master link for easily breaking the chain. I remove the chain every 300 - 400 miles for cleaning and re-lubing. The chain in question has about 2,100 miles on it. Anyway, after cleaning and re-lubing the chain I checked its wear with the Park Tool, measuring along the lower part of the chain that is under tension from the rear derailleur. For the first time since I got the CC-3 I checked the chain in several locations, rotating the crank a few degrees after each check. The chain checked out fine - the .75% wear indicator was a "no go" - except when the tool was spanning the Powerlink connector. In this region of the chain the tool indicated .75% wear, though not 1% wear. I'm tentatively concluding the Powerlink is wearing faster than the "regular" links and is the source of the "excess" wear. So: Can anyone else confirm that SRAM Powerlinks do, in fact, wear faster than surrounding regular links? Does it make sense to run a chain that's showing greater than .75% stretch in a small section of its length, or is this chain ready for retirement? TIA. Tom Young |
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#2
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A couple of SRAM chain "chain stretch" questions
TomYoung wrote:
Hi all: I've got a Park Tool CC-3 chain checker. It's one of those "go/no go" type checkers with one side registering .75% chain stretch and the other registering 1.00% stretch. (I know chains don't "stretch" per se but I'll use the phrase for convenience.) I run SRAM PC89R chains that use a "Powerlink" connector as a sort of master link for easily breaking the chain. I remove the chain every 300 - 400 miles for cleaning and re-lubing. The chain in question has about 2,100 miles on it. Anyway, after cleaning and re-lubing the chain I checked its wear with the Park Tool, measuring along the lower part of the chain that is under tension from the rear derailleur. For the first time since I got the CC-3 I checked the chain in several locations, rotating the crank a few degrees after each check. The chain checked out fine - the .75% wear indicator was a "no go" - except when the tool was spanning the Powerlink connector. In this region of the chain the tool indicated .75% wear, though not 1% wear. I'm tentatively concluding the Powerlink is wearing faster than the "regular" links and is the source of the "excess" wear. So: Can anyone else confirm that SRAM Powerlinks do, in fact, wear faster than surrounding regular links? Does it make sense to run a chain that's showing greater than .75% stretch in a small section of its length, or is this chain ready for retirement? TIA. Tom Young IMO, 1/110th of the whole chain is no biggie. -- Phil, Squid-in-Training |
#3
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A couple of SRAM chain "chain stretch" questions
Every 3/32" chain that I've used with a master link (Sram and Wipperman
chains that come with the link, and Sachs or Wipperman links on both Shimano and Campagnolo chains), the link always wears faster than the chain. If you take the link apart and clean it and examine its pins you will see grooves worn in them. The Wipperman links seem to last better than the Sram/Sachs but they cost a lot more, so I tend to use Sachs and replace them two or three times over the life of the chain. Nick "TomYoung" wrote in message oups.com... Hi all: Anyway, after cleaning and re-lubing the chain I checked its wear with the Park Tool, measuring along the lower part of the chain that is under tension from the rear derailleur. For the first time since I got the CC-3 I checked the chain in several locations, rotating the crank a few degrees after each check. The chain checked out fine - the .75% wear indicator was a "no go" - except when the tool was spanning the Powerlink connector. In this region of the chain the tool indicated .75% wear, though not 1% wear. I'm tentatively concluding the Powerlink is wearing faster than the "regular" links and is the source of the "excess" wear. |
#4
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A couple of SRAM chain "chain stretch" questions
TomYoung wrote:
Does it make sense to run a chain that's showing greater than .75% stretch in a small section of its length, or is this chain ready for retirement? I think 0.75% is too much stretch. Recommend replacing chain at 0.50% stretch (1/16" for 12 links). Quick link should be replaced at the same time. Art Harris |
#5
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A couple of SRAM chain "chain stretch" questions
As a follow up to my own post, I went and replaced the original SRAM
Powerlink with a Wipperman link - that's what the LBS had - and the chain now checks as "in tolerance" even with the tool spanning the new link. It looks like the connector link *does* wear faster than a regular link. Tom Young |
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