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This may be a totally stupid face palm question but still.
My question relates to the pins or points indicators that show the measurement, they are curved?!
So which at which point would be the correct time to change the chain?
On the top photo the pin fits into the chain, does this mean it needs replacing or is it not until the chain sits flush with the tool?
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For the Park one, and I sort of assume that the X-tools one works exactly the same; if it drops in cleanly into the position in the second picture it has stretched at least .75%. It should drop in, you shouldn't have to wiggle/push it in.
Thanks Aidy, it was a bit of a numpty question really.
I did kinda guess that but I know the park tools one has a straight edge so there are no two ways with that 1, it drops in or it doesn't. The x-tools one can fall in but not sit flush with the chain ie the first photo.
Hmm - I obviously didn't read the question properly. Sorry!
Top picture - chain wear within limits, crack on.
Bottom picture - chain worn 0.75 mm and you ave a choice. Carry on riding until the 1 mm indicator slots in and change both cassette and chain or change the chain now and the chain and cassette the next time the 0.75 mm indicator slots home.
This is just the theory put out by the wear indicator / chain manufacturers. If the chain is not slipping and all is good with gear changing, why not carry on riding but have a spare cassette and chain at home on standby.
I must just point out that those chain wear indicators measure roller wear too, which is pretty irrelevant (do a web search for why). Shimano know this, which is why their top of the range £40 odd chain wear checker does not measure roller wear at all.
Use a rule (or a ruler if HM is not busy).
At 12 1/16” (0.5%) replace chain, sprockets should be OK. As recommended by Jobst Brandt, Sheldon Brown, and me.