Data point on Gates belt life, perhaps.
We started having groaning noise when under load, pretty clearly the belt, mainly under me (captain), when going uphill. Noise was annoying, and vibration bad enough that seemed like a fair bit of energy going to make noise! Not alignment, and nothing loose. Sent a note to Gates, they said I should check BB/eccentric/cranks. I think probably 3000 miles on the belt, did not look worn, no visible wear on rings. We are just under 300 pounds and reasonably fit.
I replaced the belt, without touching anything else, and groaning noise is gone. Asked the guy from Gates if he wanted to see the belt, no response.