# Chain Wear measured, 7900 vs 7801 vs 6600



## unobtainium (Feb 28, 2005)

Recently I bought a ProGold Chain Gauge to measure chain wear, one of two such tools recommended by Leonard Zinn. This is a “L” shaped tool that is marked at 50, 75, and 100% points of chain wear. Depending on how worn the chain is, you can extrapolate the wear between these marked points. A brand new 7900 Chain will show a wear measurement of less than 50% while a new 7801or 6600 will show between 50 and 75%. The last new 7801 I installed reads 75% worn! A $15 SCRAM chain (forgot the model #) I bought for my “grocery getter” measured out at less than 50% 
After 400 miles the 7900 wear went from less than 50% to 75%.
After 300 miles the last 7801 went from about 60% to 90%
So even though the 7801 chain is cheaper, I believe the 7900 maybe a better buy.
Does anyone else have some quantitative and relative measurements on chain wear on a progressive basis?
And these measurement are based upon my meticulous cleaning n and lubing of my chains.


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## Wheelman55 (Jul 10, 2009)

You might be cleaning and lubing too much. Degreasing is tough on a chain. All you really need to do is to drip on lube, let it soak in for a while and wipe off. Some of those chain gauges will tell you that your chain is worn even when it's new. Chains are consumeables...replace them every 1500 miles or so and you'll rarely have a drive train issue.


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## unobtainium (Feb 28, 2005)

*Starting Point matters*

You're missing the point. Brand new with factory lub, never cleaned, the 7801 and 6600 chains have larger if not slopier tolerances than the 7900 or a $15 SCRAM chain. My chain whip tool has tighter tolerance like the 7900 or SCRAM! If the chain starts off with larger "stretch" then it stands to reason that it probably will not last as long as one that has better tolerances. My measurements over time bear this out.


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## Argentius (Aug 26, 2004)

1) It's SRAM, not SCRAM

2) Those chain tools are okay, but, they are not really measuring what you think they are measuring.

Shimano chains overall perform fairly well. There is a reason that race teams, even some with other sponsors, choose to buy and use Dura-Ace chains.

I've found Campagnolo ones last even longer, but, there is a significant cost premium.


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## natedg200202 (Sep 2, 2008)

I have that chain gauge. One mistake you might be making: when you insert the measuring end into the chain, make sure you just let it fall down with gravity alone. Don't stretch the chain by pushing on the cranks to tension the chain. Don't push the gauge down in any way. 

I noticed that when I let this gauge fall into the chain with gravity alone, I would get less than 50% for my chain, but if I tensioned the chain, it would go to above 75%. 

If you are using it properly on a new chain and are getting more than 75% wear, I would think you dropped the gauge and it is bent, or the chain is defective.


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## unobtainium (Feb 28, 2005)

I did not drop the tool and AGAIN it reads a lot less wear on a new 7900,SRAM, or my chain whip than a new 7801 or 6600 chain. Again, does anyone have some quantative and relative wear measurements as I have? Numbers speak louder than opinions.


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## natedg200202 (Sep 2, 2008)

Sorry for offering my opinion. Good luck on your chain wear study!


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## rustybucket (Mar 2, 2009)

I use a 12 inch rule with a chain wear tool, I have found that some chain wear tools will say that the chain is worn, but when I measure it with a ruler it is not worn.


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