HerrKaLeun

I always was a "metal ruler" guy to check chain wear because most traditional chain-checkers don't account for roller wear.

Besides Shimano and Pedro's now Park also has a proper chain checker. it always seemed hard to measure with the ruler exactly in a dark garage etc. Maybe a ruler in theory is more accurate, but it is quite hard to hold it to the same part of the pin at each end.

I finally broke down and bought this chain checker and I'm glad I did. it works really well and quickly.

GeneO 

Well they have been selling a useless tool for many years - that took them a while. I thunk I will still use my metal ruler.

Is it accurate?

HerrKaLeun

No kidding. I had a CC-2 and it showed 0.25% on a brand new chain. Worst $27 I ever spent.

Well, it is really hard to see for me if the ruler has 0.5%. I tension the chain with the crank with one hand and hold the ruler to the middle of a pin. but every time I move my eyes from one to the other pin it seems to move a bit. lol. On both my bikes the ruler looked the same to me at an estimated 0.25%. But on one bike the CC-4-dropped in, but not on the other. so my measurement isn't necessarily consistent. Also note that the chain may elongate differently over it's length. So you want to take multiple measurements. That really gets old with a ruler.

Maybe the CC-4 is still a bit overcautious, but at least not like the other tools. And the 0.5% rule is not a scientific rule. If you have cheap cassettes, it may be beneficial to keep the chains longer. if the cassette is extremely expensive compared to the chain, you may want to replace sooner. My plan is to jsut measure monthly and replace the chain when the tool falls in and be happy with that.

GeneO 

I hear you about ruler taking some time. Might give it a try, Put it on my wish list. I mean it is $15, probably the cheapest tool I have purchased and have a lot LOL.

HerrKaLeun

My excuse is that now chain checking is more fun and I do it more often. That way I don't miss changing a chain in time. It only takes saving one cassette or chainring not being wasted to pay for the tool. Also a good tool to evaluate used bikes and knocking off the price 😀

DiabloScott

This is exactly what it says in the instructions:

There is zero chance that relying on proper use of this tool will result in over-stretched chains and cassette/chainring damage. The worst case is you throw away a chain that still had some life in it.And even if your objective is to get maximum chain life, you can still use it as a first check and then switch to the ruler when you pass the mark.

I have rulers too, but the CC-2 is so damn easy to use it's my go-to device. The real advantage is you can use it where the light isn't so good or in tight spaces where you can't see, and then take it off to read it in better conditions.

smashndash

I, too, refused to buy a chain checker that didn’t account for roller wear/size. Too many stories of those things failing new chains. I bought a 6” ruler and 12” ruler instead.

Without taking the chain off, I had great difficulty using the 12” ruler. I assume you’re supposed to measure the chain under tension, so I tried to measure the upper drive portion of the chain. I couldn’t really fit the 12” ruler in there. So I tried the 6”. If my math isn’t wrong, 0.5% of 6” is 0.03 inches. 1/4 of 1/8”. How am I supposed to eyeball that? And how do I know I haven’t just positioned my ruler wrong? Heck, even with the chain off, 1/16” seems mighty hard to eyeball. Maybe I’m not doing it right. And if I’m being honest, I’ve compared rulers before and definitely seen ones that were off by that amount across 12”.

Anyway, I bought the CC4. Glad a skeptic like me is having a good experience. I’ve yet to use it

GeneO 

I did pick one of these up and it appears to work well on my unstretched chain. Only minor complaint is you have to put a finger around the chain to properly tension it and this gets grease on ya.

It is an improvement over the CC-3.2.

Thanks for the heads-up.

noglider 

My imprecise way of checking a chain is to put it on a big chainring and pull to see how much of a gap there is between chain and teeth.

DaveSSS 

Actually, it's the new model that doesn't account for roller wear. In theory, it checks the change in length, just like a ruler. The change in length is a true measure of the change in pitch, but that is due entirely to wear between the pins and inner plates and has nothing to do with the rollers. The old models exaggerated the elongation, by adding the roller wear and elongation. Campy chains don't increase in length nearly as much as most other brands. If the new park tool or a ruler is used to measure the length only, you may find .25% elongation after 6000 miles, but that does not mean that the chain is not worn out. The rollers and side clearance between plates will show extreme wear after this much use and the cassette it was used with will most likely have sprockets that skip with a new chain. Campy recommends a length check between the rollers, that is mostly roller wear and only a small amount of elongation. Both should be measured separately, if you really want to know what part of the chain in the most worn.

smashndash

I believe campy specifically uses softer, quicker wearing rollers (probably to save your cogs) so that may be an issue specific to them. I’ve also heard that, when it comes to meshing issues and excessive cog wear, roller wear is not as much of a problem as elongation. I’m sure roller wear isn’t harmless but I doubt it has the same consequences as elongation. If that is the case, then it doesn’t make sense to lump roller and pin/link wear into the same measurement. As you’ve said, the measurements ought to be separate

GeneO 

It is the change in length/pitch that wears out gears. Who cares about anything else?

DaveSSS 

ABsolutely wrong. That's why I deliberately used a Campy chain for 6000 miles - to test Jobst Brandt's contention that only elongation would cause sprocket damage. My chain had no more than .25% elongation, but two of the most-used sprockets skipped with a new chain. Campy rollers don't wear faster than others. Their inner plates and pins wear far less than any other brand. I used a cheap kmc 11.93 chain for only 1000 miles and had .25% elongation.
The smartest thing to do is alternate the use of several chains, so the sprockets don't wear-in to match small rollers or an elongated chain.

GeneO 

Since I am absolutely wrong, I would like to hear an explanation from you of how roller wear causes cog wear.

It is fairly straightforward to me. The chain wears before the cogs, The pitch of the cog teeth and the elongated chain don't match so there is friction and the cog teeth will wear to match the pitch of the chain. This happens where the chain is under tension - as it goes onto the sprocket and as it comes off.

HerrKaLeun

My ruler is metric and imperial. For shorter chainstay bikes I use the metric measurement of 10 links. 25.4 cm is new, 25.5 mm is 0.5% elongated. I always measure on the bike, after all this is just to test... the chain comes off when it gets replaced.

Yeah, I also questioned the ruler accuracy. but new chains were exactly 12" with my ruler when stretched.

And yes, it is really hard to read and keep the ruler at the same part of the pin on both sides while stretching the chain.

You can tension with the crank when the rear wheel is on the ground.

GeneO 

Not how the CC-4 tool works. Three point system (2 anchor, 1 measure) and you need to use finger tension on the chain between the two anchor points.

HerrKaLeun

Thanks. I didn't realize that. Looked back at the Parks page and you are right. Well, I wear gloves for most work anyway.

Good I kept that chain I replaced. Maybe it is still good. But the new chain shifts better......

davidad

I have had the Rohloff checker for over 20 years. I found out that a ruler was a better tool for the purpose because I had been discarding chains with plenty of life in them. I have the Pedros now and it is reliable. Looks like Parks plagiarizer it. https://pedros.com/products/tools/ca...ecker-plus-ii/

GeneO 

Pedro's looks like it has instructions right on the tool

Shimagnolo

About damned time Park got around to it!
I bought the Shimano tool years before the Pedro's tool was released.
I got it on sale, but it still cost way more than it should have.

DaveSSS 

To make an accurate length measurement with a ruler, use a precision 12 inch machinist's rule. Place one end on the edge of a pin. When new, the pin at the other end will be completely covered by the ruler. When that pin is half exposed, you have slightly more than 0.5% elongation. Check the chain when it's off the bike for cleaning, laid out on a table top and stretched snugly. If you never take the chain off for cleaning, don't expect the best chain life. Also don't use this method with a Campy chain. You'll ever get it to show 0.5%.

jadocs

Exactly this...I was going to say you don't try to measure from the center of a pin, you start at the edge it's more precise.

DaveSSS I do have one question though, why is it preferable to take the chain off the bike to measure vs. measuring on the bike with the derailleur applying tension?

Concur with your comment about "if you never take the chain off for cleaning...not to expect the best chain life".

DaveSSS 

I would measure the chain off the bike, just because you can lay a ruler on the chain much more easily, without having to hold it in place.

Since I mainly use Campy chains, the ruler is worthless, so I either use calipers as suggested by Campy, or a plug gage that I made from a 6mm hex wrench to drop between the rollers. The Campy method figures out to .75% elongation, but the vast majority of what you're measuring is roller wear and it's mostly wear on the holes in the rollers, not the OD of the rollers.

By alternating the use of several chains, the wear measurement is far less critical, since you'll never get new-chain skip, Each chain can be used longer, but too much longer might shorten the life of chain rings. I'd still expect the chain rings to last the life of two cassettes.

Racing Dan

I Eventually moved in the other direction, including the roller wear. Reason being, a chain that is still not significantly elongated may have severely worn rollers. Including roller wear you can however get away with much more wear than usually recommended. Up to 1% no problem, compared to the new chain, id say.

GeneO 

I like this guys approach to demonstrate effects of roller vs. elongation wear. That must have been some worn chain. LOL.

https://bike.bikegremlin.com/3370/ro...th-chainrings/

But yeah, I get it. Roller wear could effectively reduce the pitch of the chain as it disengages, but I am not sure whether this actually is what happens,.I think the forces on neighboring rollers as the come off the chain are in the same direction, so roller wear doesn't come into play.

EDITED to clarify.