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Should bike shops be trusted to measure chain wear?

3400 Views 44 Replies 25 Participants Last post by prj71, Nov 9, 2021

TylerVernon

Discussion Starter · Nov 7, 2021

I was hanging out at the LBS the other day, and the mechanic was working on a nice xc bike with XX1 Eagle. He grabbed the chain checker and let out a sigh of admiration, "Wow, these Eagle chains just last forever".

Agreeing, I say "Yeah, I never wear out chains. I have 18 months on an XTR chain that shows barely any wear. I measure with either a ruler or by hanging the chain next to a new chain."

He challenged me on that statement. I asked him How much you want to bet? I have my bike in the back of my truck, I can bring it in right now.

He bets five dollars. Fine. I bring in the bike and he uses one of those analog tools like a Park CC3.2 that fits in between the rollers. "Your chain is a little over 0.7, so you'll need to replace it soon", he says.

"Are you SURE?" I ask. He checks again and re-affirms his reading.

"Because that's a brand new HG901 chain. I totally psyched you out. That chain has like two rides on it. I put on a new chain recently because I wanted a shiny one".

He looks at me like he wants to torture me slowly and checks again. "Err, looks like about 0.5, I guess....." "oh not so sure now, I see."

Doing a pin to pin check with a 12" ruler, the chain measures zero wear to my eye.

Yeah, it was a dirty move, but I've been watching lbs over-estimate chain wear for years and I wanted to make a point.

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Sparticus

· #2 · Nov 7, 2021

Yeah that was a dirty trick. Shame on you.

I know some awesome bike shop mechanics — they’re out there for sure and I respect them. Not just for their mechanical talents but also for being willing to choose a generally under-rewarding, underpaying career that requires them to work all through the summer when everyone else is taking vacation and riding their bikes. (Most bike mechanics got into their jobs because they love cycling.)

That said, I never know which employee at the shop is going to work on my bike, so I don’t leave my bike at the shop unless there’s simply no other way to get the job done. IME for every awesome bike shop mechanic, there are a few whose hands I don’t want my bike falling into.

In other words I do all my own wrenching unless I simply can’t.

As for chain length checking — I can do that.

=sParty

Reactions: 4

J.B. Weld

· #3 · Nov 7, 2021

TylerVernon said:
Yeah, it was a dirty move, but I've been watching lbs over-estimate chain wear for years and I wanted to make a point.

Working at a lbs I mostly see the opposite, people bringing in bikes with totally thrashed chains and then needing to replace every drivetrain component.

Agree that not every bike shop employee (or any shop employee) is completely fluent in their craft but generally it's better to replace a little too often than the other way around.

Reactions: 5

006_007

· #4 · Nov 7, 2021

TylerVernon said:
I was hanging out at the LBS the other day, and the mechanic was working on a nice xc bike with XX1 Eagle. He grabbed the chain checker and let out a sigh of admiration, "Wow, these Eagle chains just last forever".

Agreeing, I say "Yeah, I never wear out chains. I have 18 months on an XTR chain that shows barely any wear. I measure with either a ruler or by hanging the chain next to a new chain."

He challenged me on that statement. I asked him How much you want to bet? I have my bike in the back of my truck, I can bring it in right now.

He bets five dollars. Fine. I bring in the bike and he uses one of those analog tools like a Park CC3.2 that fits in between the rollers. "Your chain is a little over 0.7, so you'll need to replace it soon", he says.

"Are you SURE?" I ask. He checks again and re-affirms his reading.

"Because that's a brand new HG901 chain. I totally psyched you out. That chain has like two rides on it. I put on a new chain recently because I wanted a shiny one".

He looks at me like he wants to torture me slowly and checks again. "Err, looks like about 0.5, I guess....." "oh not so sure now, I see."

Doing a pin to pin check with a 12" ruler, the chain measures zero wear to my eye.

Yeah, it was a dirty move, but I've been watching lbs over-estimate chain wear for years and I wanted to make a point.

But....did he pay up the fiver?

Reactions: 5

TylerVernon

Discussion Starter · #5 · Nov 7, 2021

The shame he felt was worth way more than a fiver.

Reactions: 1

rideit

· #6 · Nov 7, 2021

I have four chain-checking tools (and a ruler), and they all measure differently (except for the ruler). But it is easy to be a mm off even when using the ruler!
At my shop 20 years ago, I had a finish nail on the wall, with exactly 12” denoted below it. Measured the same way every time.
But you had to take the chain off.

Reactions: 3

Shark

· #7 · Nov 7, 2021

I use the ruler method, never fails!

Sent from my SM-G991U using Tapatalk

Reactions: 4

ctxcrossx

· #8 · Nov 7, 2021

rideit said:
I have four chain-checking tools (and a ruler), and they all measure differently (except for the ruler). But it is easy to be a mm off even when using the ruler!
At my shop 20 years ago, I had a finish nail on the wall, with exactly 12” denoted below it. Measured the same way every time.
But you had to take the chain off.

I also use the ruler method. I ended up buying a cheap 6 ft aluminum ruler. Bolted half of a quick link that is aligned to zero and I use that. I get much more precision using 4 ft as opposed to 1 to measure, and it's no more work since the chain is off either way. Having the quick link at the top also means I just throw it on and it's at the same location each time for consistency.

Edit:. Offset 1-in just for simplicity.

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Reactions: 5

kevin_sbay

· #9 · Nov 7, 2021

TylerVernon said:
He bets five dollars. Fine. I bring in the bike and he uses one of those analog tools like a Park CC3.2 that fits in between the rollers. "Your chain is a little over 0.7, so you'll need to replace it soon", he says.

"Are you SURE?" I ask. He checks again and re-affirms his reading.

Did u see him use the tool and insert it into the chain links? How did the tool fit in to show 0.7 wear, if your chain was new?

rockman

· #10 · Nov 7, 2021 (Edited)

The older style tools don't work as well for 11 sp and 12 speed chains. A lot of shop mechanics don't know that. The chain may not show stretch but the rollers are worn out. And that wears out the cassette and chainring. There's some info in here: Finding the best bicycle chain: What over 3,000 hours of testing revealed - CyclingTips

This tool works pretty well: https://www.parktool.com/product/chain-checker-cc-4

J.B. Weld

· #11 · Nov 7, 2021

For diagnosing repairs in a shop situation chain measuring tools work fine imo. You do have to know which one to use and how to use it.

J.B. Weld

· #12 · Nov 7, 2021

rockman said:
The older style tools don't work for 11 sp and 12 speed chains. A lot of shop mechanics don't know that. The chain may not show stretch but the rollers are worn out. And that wears out the cassette and chainring. There's some info in here: Finding the best bicycle chain: What over 3,000 hours of testing revealed - CyclingTips

This tool works pretty well: https://www.parktool.com/product/chain-checker-cc-4

That's a fact, a sram 12 speed chain with over a thousand miles on it can measure like brand new when using roller to roller measuring tools.

Cary

· #13 · Nov 7, 2021

Any tool is only as good as the person operating it.

Reactions: 1

Sparticus

· #14 · Nov 7, 2021

ctxcrossx said:
I also use the ruler method. I ended up buying a cheap 6 ft aluminum ruler. Bolted half of a quick link that is aligned to zero and I use that. I get much more precision using 4 ft as opposed to 1 to measure, and it's no more work since the chain is off either way. Having the quick link at the top also means I just throw it on and it's at the same location each time for consistency.

Edit:. Offset 1-in just for simplicity.

Very nice — I like your idea.
Here’s the chain checker I’ve used for a hundred years:

Wood Font Rectangle Knife Measuring instrument

There’s a ‘roller hook’ on the back that nestles over a roller (lines a pin up with the hole near the left end) and then I look through the 4 holes on the right to see which hole another pin lines up with near the other end of the checker. These 4 holes on the right are progressively farther apart and labeled, “new, good, fair, replace.”
I always replace my chains whenever they reach “fair.”
=sParty

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kevin_sbay

· #15 · Nov 7, 2021

Learning a lot in this thread. Thanks everyone!
I've just been using the Park cc3.2 tool, though incorrectly I just found out. From Park: "For 9 and 10-speed chains, replace chain just as the gauge fits the 0.75% side fits flat into the chain. For 11 and 12-speed chain, replace as the 0.5% side fits."

eb1888

· #16 · Nov 7, 2021

A ruler works if you keep the chain under tension as you measure.
I use the Shimano TL-CN42. Amazon link.

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 in the article above.

The alternative has the `toe'' and the heel'' on the same sides of each of two rollers. 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 of the two rollers, no roller wear error is added to the measurement. So it doesn't matter how worn the rollers are. They don't affect the wear of the other drive components.

The CN42 is a good choice at a lower cost. It measures wear above 5 inches between the back of two rollers under tension.
The split end pushes the rear split body of the tool against the back of a roller. Pushing this worn roller against the bushing/pin assembly.
When the front end is rotated down it pushes the corresponding back of a worn roller 5 inches plus the wear amount forward against that bushing/pin assembly. If the chain is worn enough to need replacement the front edge will drop in. Worn rollers have no affect on the measurement like they do with other tools.

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slimat99

· #17 · Nov 7, 2021

Not to take the shops side because I know some of those guys don't know their ass from their elbows, but XTR chains come with a little bit of stretch brand new compared to XT. This is partly how shimano achieves better efficiency. It's also proven that sram 12 speed eagle chains last longer than any chain on the market. They also have poor efficiency because of that. You can look up the data to back this up if you want. Some guy spent 10k on equipment to do third party testing. PB did a article on it a while back. Sram got defensive over the efficiency stuff, but they should have been proud of how durable their 12 speed chains are. No statement from shimano about the slightly stretched xtr chains that I remember.

Reactions: 1

ctxcrossx

· #18 · Nov 7, 2021

Sparticus said:
Very nice — I like your idea.
Here’s the chain checker I’ve used for a hundred years:
View attachment 1955879
There’s a ‘roller hook’ on the back that nestles over a roller (lines a pin up with the hole near the left end) and then I look through the 4 holes on the right to see which hole another pin lines up with near the other end of the checker. These 4 holes on the right are progressively farther apart and labeled, “new, good, fair, replace.”
I always replace my chains whenever they reach “fair.”
=sParty

Thank you! I love your chain wear tool. I've been around bike tools for quite some time but I've never seen that one before. Who makes it?

OneTrustMan

· #19 · Nov 7, 2021

slimat99 said:
proven that sram 12 speed eagle chains last longer than any chain on the market. They also have poor efficiency because of that.

I think I'm not alone on this when I chose longer lasting chains over a tiny bit more efficiency.

But to be clear, it's Srams x01 and XX1 chains ( 11 and 12 speed) that last this long. The lower end GX and NX chains come not even close.

Reactions: 3

Sparticus

· #20 · Nov 7, 2021

ctxcrossx said:
Thank you! I love your chain wear tool. I've been around bike tools for quite some time but I've never seen that one before. Who makes it?

I’ve had my chain wear indicator for decades. The sticker on it says “MFG BY SPEEDTECH, MT. VIEW, CA.” I googled that and today it appears to be a muscle car company.

=sParty

P.S. This thing is so old that the three grooves on the top are labeled, “3/32 narrow,” 3/32 standard” and “1/8 standard” for measuring the width of bike chains in use at that time.

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