I went to the Gates site, to see if there was any news about their CenterTrack belt. There wasn't. Of interest, however, was the news that Gates has released a free iPhone app by which to gauge the tension of a Gates belt.
Carbon Drive Bicycle Calculator
Originally Posted by iTunes App Store
See also, from Gates:
Tune Up Your Belt: Sonic Tension Tester iPhone App Now Available from iTunes
So, I excitedly downloaded the App, and then sought to enter the specs for the Gates drive on my tandem.
Hey, there was an option neither for the 69 or 74 teeth in a Gates tandem sprocket, nor for the 250 tooth tandem belt.
I guess Gates is telling us how they feel about tandems.