How about taking the chain off the chainring (so it becomes slack), forming a u-shape with the chain, and then trying to insert each end of the chain checker tool (one end at a time) into one of the chain links?
That should allow you to be sure that it's too thick
How about taking the chain off the chainring (so it becomes slack), forming a u-shape with the chain, and then trying to insert each end of the chain checker tool (one end at a time) into one of the chain links?
That should allow you to be sure that it's too thick