I’ve been running the cog drive setup since 2006 or 2007 and would be replacing the belt about every year or so. In my case it would tear the teeth off the belt.
I noticed the 1760 belt was very “tight” on the pulleys and, in my opinion, it was running hot causing the breakdown of the rubber and a cog belt doesn’t have to run tight.
So, I bought an 1800 length belt and been running it for many years without issue. In fact I can’t remember the last time I replaced the cog belt… I know it’s been longer than 6 years.
This is the belt I use, get them at NAPA. Expensive? Yeah. But they last. Only reason I broke one is one of my idlers came off while driving, and the belt got hooked on something. Idlers turn in the direction that favors loosening, so from that point on, Blue LokTite all the way. I have one of Brett's manual tensioners, and don't run it any tighter than the stock tensioner did.