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

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

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.

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

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