Found out most chain wear gauges are off by 0.25% right from the factory

Read a post on a Park Tool forum last Tuesday where a guy tested 5 different brand new gauges against a caliper and only 1 was actually accurate, has anyone else bothered to check theirs against a real measurement tool?

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2 Comments

piper_green2mo ago

Wait did you actually measure them with a caliper yourself? I used to think the whole "chain wear gauges are off" thing was just people being overly picky about tools that are cheap enough to not matter. But after reading this I actually grabbed my own cheap gauge and a caliper and yeah, it was off by almost the same amount. Kinds wild how something so basic can be that wrong from the start, you'd think they'd check it before shipping. Definitely gonna keep this in mind next time I'm buying parts, not just trusting what the tool says.

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anthony_fox902mo ago

you'd think they'd check it before shipping" - that's the thing though, they probably do check them but just with a batch sample. I work around tools all day and it's common for factories to only test 1 out of every 500 gauges or something. The real issue is that most of these cheap gauges are stamped out of thin metal and the tolerances just aren't tight enough. That 0.25% difference doesn't sound like much but when you're trying to decide if a chain is at 0.5% or 0.75% wear, a quarter percent off either way can make you replace a chain way too early or way too late. I've started just using the gauge as a rough indicator and double checking with a ruler if I'm unsure.

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