Originally Posted by
Stucky
Actually, it's the wear in the rollers which causes "stretch"- so measuring the chain with a ruler or a chain-checker, is pretty much an easy way to assess the condition of the rollers. No stretch: The rollers are good.
Exactly if the pins do not line up then the rollers have wore and that equals a longer chain. Chain checkers just are inaccurate and will show wear on new chains, this has been shown many times.