The main visible difference between an old chain and a brand spank one is the links get sloppy and the chain can shift more laterally. A new chain is pretty stiff laterally when held on its side, an old one isn't. As said above this is what causes stretch. You don't really need a ruler or anything to check this.
The main visible difference between an old chain and a brand spank one is the links get sloppy and the chain can shift more laterally. A new chain is pretty stiff laterally when held on its side, an old one isn't. As said above this is what causes stretch. You don't really need a ruler or anything to check this.