LV2TNDM

This isn't a bad idea. However, "stronger" may not mean longer life. But given the higher torques ebikes put out, common sense would say an ebike chain SHOULD last longer. Tensile strength would be the "brute strength" metric that would describe "strong." However, it isn't really important on a timing chain because only one rider is applying force to it. If you were to improve tensile strength anywhere, it would be the main chain since it's having to withstand the force of two riders. But this isn't what breaks most chains anyway - it's usually applying full force while shifting, which pops a side plate off and the chain separates.

I think you're trying to improve durability to reduce "stretch" or elongation. There are myriad parameters that go into making a chain. Quality steel, heat treating and plating are probably the three most important. Get the right combination, and you can have a very durable chain. However, which brand is best??? That's the million dollar question to which there is really no objective answer.

It would be nice to have an independent chain testing organization that could put chains through proper testing to determine durability. There are people out there testing chains and lubes, but they all seem to have an axe to grind - either promoting their brand of chain or chain lube. Hard to find true objectivity.

But the problem there is that product models are constantly changing as are those producing the chains. So while one brand and model could be the test winner, two months later the model could go out of production, or the manufacturer switch producers, change specs, pick lower cost materials, or other cost-saving measures you'll never know about. In other words, it's hard to find "the best" that persists as the best.

All that said, I know Co-Motion uses 6,7,8 speed chains for their tandems under the assumption that a wider chain has more beef and metal, and should therefore last longer. But again, it depends on the materials and production processes.

I just picked the KMC all-silver chain as my go-to replacement. It seems to get good reviews, so I bought a bunch. I just replaced the 30-year old Sedisport Silver chain on my road tandem. The timing chain actually has virtually no measurable wear, but the main chain is just about 1/16". Either way, time to replace. Turns out the KMC shifts much better. Better on my road bike as well.

I still cannot believe I got that much time out of my original road tandem chain. I haven't put that many miles on that bike, but certainly not zero! The Sedis Silver was THE durability winner in my book. I wish I bought a case of 'em back in the day! Oh well, we'll see how the KMC's last.

And the timing chain ring swap suggestion is excellent. It's a great way to double the life of one tandem component.

Good luck.