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Chain wear...an observation.

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Chain wear...an observation.

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Old 12-03-17, 04:56 PM
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gearbasher
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Chain wear...an observation.

Don't worry, this isn't another chain wear/measuring/lube thread. That horse has been beaten more times than the NY Giants. This is an observation. But I have to mention measuring. Sorry.

Since my eyesight isn't the greatest anymore, I use a Park chain wear indicator. I've tried others and find the Park is the most accurate. This is not a plug for Park tools. I find them hit or miss. I also use either KMC or Sram chains w/ quick links.

My observation is: When the chain is getting close to the Park tool's .5 go/no-go threshold and I'm measuring the chain with the indicator straddling the quick link, the chain indicator will drop in (showing it's at the .5 point of wear). Anywhere else and the chain checks out fine. So, I guess either the quick links are wearing faster than the other links or they aren't manufactured to the greatest tolerance.

Just an observation on a boring Sunday evening. Thank you for your time.
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Old 12-03-17, 05:47 PM
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two more wear points... the inside of the keyholes!
regular chain wear is just the pins/rollers... the quick link adds two more wear points to the total.
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Old 12-03-17, 05:52 PM
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Which is why we don't use a chain wear tool straddling the connecting link and make at least two checks at two different locations. Andy
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Old 12-04-17, 09:54 AM
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Hadn't noticed that. If that can be confirmed, sounds like it'd be a good idea to buy an extra quick link with every chain and replace the QL when it starts to wear - cheaper than a whole new chain, anyway.

@maddog34 , I think there's actually one less wear point on the QL. Side links have one wear point per pin, each (4 wear points per link). QL can only wear on the hole side, since the QL sideplate is attached to the pin: 2 wear points per link.
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Old 12-04-17, 12:17 PM
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Originally Posted by pdlamb View Post
maddog34, I think there's actually one less wear point on the QL. Side links have one wear point per pin, each (4 wear points per link). QL can only wear on the hole side, since the QL sideplate is attached to the pin: 2 wear points per link.
inner links wear on the inside of the rollers... outer links wear on the surface of the pins... both experience wear on the inner or outer plate surfaces, but that wear does not effect "length of chain"... the keyholes wear at the engage points.
two extra wear points introduced by the quick link.
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Old 12-04-17, 01:05 PM
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Originally Posted by maddog34 View Post
inner links wear on the inside of the rollers... outer links wear on the surface of the pins... both experience wear on the inner or outer plate surfaces, but that wear does not effect "length of chain"... the keyholes wear at the engage points.
two extra wear points introduced by the quick link.
At the risk of opening up a can of worms...

I'm not sure that's true of quick-links. The pins, once locked into the side-plates, do not rotate with respect to the plates, so there should be no wear there. The pins, passing through the inner plates and rollers, will wear the same as the pins in any other chain link.

For the three-piece type of link, the side plates on the quick-link (one fixed and one removable) are under tension. The "locking" part with the keyholes simply holds the removable plate in place.

Also, the wear that accounts for lengthening of the chain occurs between the pins' surfaces facing the center of the link just inboard of the outer plates, and the surface of the holes (or bushings) in the inner plates toward the ends of the plates. Roller wear doesn't contribute to chain elongation except when a chain checker is used that does not push the rollers in the same direction (discussed elsewhere at length).

I hope I have this right!
Steve
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Old 12-04-17, 10:36 PM
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Originally Posted by pdlamb View Post
Hadn't noticed that. If that can be confirmed, sounds like it'd be a good idea to buy an extra quick link with every chain and replace the QL when it starts to wear - cheaper than a whole new chain, anyway.
I actually tend to measure across the quick link because I expect an accelerated wear around there. Once the quick link loosens, the adjacent link experiences an increased load and an avalanche develops. Changing QL early should be indeed the solution
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Old 12-05-17, 01:04 PM
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Originally Posted by sweeks View Post
At the risk of opening up a can of worms...

I'm not sure that's true of quick-links. The pins, once locked into the side-plates, do not rotate with respect to the plates, so there should be no wear there. The pins, passing through the inner plates and rollers, will wear the same as the pins in any other chain link.

For the three-piece type of link, the side plates on the quick-link (one fixed and one removable) are under tension. The "locking" part with the keyholes simply holds the removable plate in place.

Also, the wear that accounts for lengthening of the chain occurs between the pins' surfaces facing the center of the link just inboard of the outer plates, and the surface of the holes (or bushings) in the inner plates toward the ends of the plates. Roller wear doesn't contribute to chain elongation except when a chain checker is used that does not push the rollers in the same direction (discussed elsewhere at length).

I hope I have this right!
Steve
the contact surface in the keyhole is REALLY THIN material... impact wear instead of friction wear.

i'll leave the other worms in the can....

Last edited by maddog34; 12-05-17 at 01:18 PM.
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Old 12-05-17, 01:36 PM
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Originally Posted by maddog34 View Post
the contact surface in the keyhole is REALLY THIN material... impact wear instead of friction wear.
Hmmm... I had not considered that possibility. Thanks!
Steve
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Old 12-05-17, 02:33 PM
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Originally Posted by sweeks View Post
Hmmm... I had not considered that possibility. Thanks!
Steve
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