Originally Posted by
banerjek
The only issue with using a chain checker over measuring is that they don't take roller wear into account so reading may be exaggerated.
That's not quite right. The tools will often report .25% wear when a chain is new, but it's due to smaller diameter rollers and/or larger roller clearances. A Shimano or KMC chain may measure .210-.215 inch between the rollers, when new, while a Campy chain only measures .200 inch. The chain checking tool is made to report no elongation with a chain that measures like Campy. Any initial wear is totally false and should be subtracted from future readings.