conspiratemus1

The reason I asked about the eccentric was that if you adjust and maintain your bicycle properly you will not need to waste time searching for magical mythical stretch-proof Superchains that won’t fall off despite zero maintenance. All chains and rings wear. Eventually your timing chain will become slack. And then it will fall off. The problem is not the chain. It’s you.

if your tandem is 17 years old and has never had either chain replaced, likely the timing rings and the rear sprockets will be too worn for new chains to mate properly. The new chains will lift and skip on the old sprockets/rings — that’s how they tell you they are worn out. On the front, that means the chain will fall off. Again.