I am one of those guys that buys economical freewheels and chains. I also ride allot of dusty trails so I end up cleaning my chains frequently. I have wasted my money on three different chain-wear tools and none of them beat my ruler so I am sticking with that. Further more I have finally learned that replacing bike chains is much better then replacing cogs and rings. Bill's 3' trick is one I am going to use from now on...
Originally Posted by
Bill Kapaun
...use a 3' section of tape measure. It'll give you 3X the resolution vs checking a 12" section. I use the 1 & 37" marks to avoid dealing with the hook.
That would give a little better idea of the chain checkers true error...