# chain wear indicator



## sanjayc (Jan 20, 2011)

Hi, 
I was just reading this link for info on chain wear indicator:
http://forums.mtbr.com/tooltime/park-chain-wear-indicator-tools-cc-3-vs-cc-3-2-a-738334.html

After reading the above and few other links, it appears that Shimano tools are more accurate. The TL CN41 is recommended, but is expensive. I have seen a less expensive checker from Shimano called TL CN42. How is the TL CN42?

I was looking at Park tools CC2 or CC3.2 , but after reading the threads, I was thinking of shimano tools. I have a 9 speed alivio system, not sure of the chain.

Thanks in advance.


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## AndrwSwitch (Nov 8, 2007)

I just use a tape measure.
http://sheldonbrown.com/chains.html#wear


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## DennisF (Nov 4, 2011)

The problem with most chain checkers is that they count roller wear, which doesn't matter. The Shimano CN41 is not fooled by roller wear. Looking at the picture of the CN-42, it looks like it is like other checkers and would be fooled by roller wear.

The good news about the CN-42 and the Park checkers and most other checkers is that they are conservative. If it says you are at .7% wear, you can be sure that it is NO WORSE than .7%, and worst case just end up replacing the chain a little earlier.

The ruler works fine. However, I use a Park CC2 because it is convenient and gives an indication of how much the chain is worn, not just go/no go. Not horribly expensive either. I check the chain every month or so and record the reading to see how it is wearing.


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## eb1888 (Jan 27, 2012)

http://pardo.net/bike/pic/fail-004/000.html
The CN42 does NOT measure between rollers. It is placed on the same sides of the rollers like the proposed alternative pictured above.

The alternative has the ``toe'' and the ``heel'' on the same sides of the roller. Again, the ``toe'' is placed precisely at the distance of too much wear. Thus, the ``toe'' only fits over the roller when there is too much wear. By placing both heel and toe on the same sides, no roller wear error is added to the measurement.

The CN42 is a good choice at a lower cost.
The split end pushes the body of the tool against the back of a roller pin assembly and pushes the worn roller against the bushing/pin
When the other end is rotated down it pushes the corresponding back of a roller pin assembly pushing the worn roller against that bushing/pin.


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## Blackhawks01 (Oct 8, 2013)

I use a Park CC-2 as well. Great little tool, easy to use/read.


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## veloyellow (Aug 23, 2009)

I do maintenance in my garage, where I made a simple setup for this (I use power links):

1. use a convenient location (inside of an upper cabinet door for me) to hammer a brad in place - it must fit thru the chain link.
2. hang a new chain on this brad
3. count twelve links down, and mark a line (on the door) where the pin center is
4. also mark a line precisely 1/8" below this one

If you replace chains when they've "stretched" 1%, do so when that pin center reaches the lower line. (I replace when 1/2% is reached. YMMV.)

I'm not sure this helps unless you use powerlinks, or equivalent, and remove the chain for maintenance, as I do.
It helps to place the brad at such a height that the marks fall at eye level.


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## HillbillyTom (Sep 15, 2012)

AndrwSwitch said:


> I just use a tape measure.
> Chain Maintenance


Same here. Trusty ruler has served me well on both bicycles and dirt bikes for years.:thumbsup:


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## sanjayc (Jan 20, 2011)

Hi, I have a 2011 trek mtb with alivio system from shimano. It has 9 cogs in rear. will parktool CC2 work with this model? Its 9 speed chain drive. I


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## kapusta (Jan 17, 2004)

sanjayc said:


> Hi,
> I was just reading this link for info on chain wear indicator:
> http://forums.mtbr.com/tooltime/park-chain-wear-indicator-tools-cc-3-vs-cc-3-2-a-738334.html
> 
> ...


I am at a complete loss as to why people don't just use a 12" steel ruler:skep:

Way cheaper and completely accurate.


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## DennisF (Nov 4, 2011)

sanjayc said:


> Hi, I have a 2011 trek mtb with alivio system from shimano. It has 9 cogs in rear. will parktool CC2 work with this model? Its 9 speed chain drive. I


Yeah, it will work with any chain. The distance between the pins is a half-inch regardless. The difference between chains made for different number of speeds is the width of the chain.


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## sanjayc (Jan 20, 2011)

Thanks all. Thanks Dennis, it makes sense. I picked up the CC-2 and tried it. I have around 400 miles on the bike on paved roads and it showed 1 and between 0.5 and 0.75.

I am wondering if I am pushing the gauge too hard and it also seems a bit stiff while pushing. When I tried to take the gauge from the chain , it had pressed against rollers on both ends. I parked my cycle with sidestand and put the gauge onto the chain.

What might I be doing wrong?


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## DennisF (Nov 4, 2011)

Yeah, it's hard to believe that you would practically wear a chain out in 400 miles on pavement even if you never lubed it. 

Don't push too hard on the CC-2's little black indicator thingy -- just so the pins touch and it is snug is all you need. There is a lot of leverage there, so if you push too hard it seems to me that you could bend the pins. Also, the instructions say to insert the stationary pin between two outer plates and the movable one between two inner plates. I can't imagine why this would matter however.

I guess it is possible that the CC-2 is defective for some reason -- bent pin(s) or the pivot hole not drilled at the right place or something.

I would check it with a ruler and compare. I figured that 1' + 1/16" = .52% wear, and 2/16" would equal 1.04% wear (now I remember why I brought the CC-2). 

If you measured 2' of chain, 

1/16" = .26%
2/16 = .52%
3/16 = .78%
4/16 = 1.04%

You would be wise to check my math  .

If you could find a ruler marked in 32nds that would be good, or you could eyeball it pretty close.

The ruler should measure the same or less than the CC-2 because the ruler is ignoring roller wear (which is good actually). How much less I have no idea. Anyway, it would be interesting to compare. Or ask around and see if anyone else at the trail has a CC-2 to compare, or take it to your LBS -- ours has a CC-2 on the counter for anyone to use. 

For reference, I got a new KMC top-of-the-line chain. It was at 0% wear when new. Now, about 1700 miles later, all dirt, two races in mud with dry lube, it is slightly over .5% as per the CC-2. I am pretty religious about keeping it cleaned and lubed. I will compare the CC-2 and ruler measurements the next time I have it off.


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