At some point I got two strap wrenches with rubber straps. No reinforcements, just pure rubber or neoprene or whatever. I’d cinch up on something, apply some torque, and the straps would stretch beyond belief. I’d always wanted to replace the straps and, finally, when I had the shop replace the van’s belts, I asked for a timing(*) belt from their scrap can.
The smaller wrench required slitting the belt lengthwise and discarding two ribs. A pop rivet attaches two small chunks of the belt to form a block; the original belt had a molded-in triangular end:
The larger belt required a plastic filler, cut from something that might once have been a flag holder, riveted into a loop that firmly jams inside the wrench handle:
Nothing fancy, but strap wrenches work much better when the straps don’t stretch!
Found these pix while I was looking for something else…
(*) As Dan points out in the comments, this is a serpentine belt. I got it while the shop replaced the Sienna’s timing belt; that’s my story and I’m sticking with it…
The Smell of Molten Projects in the Morning 
I suspect the torque limiter now will be, “when the wrench handle breaks.”
‘Cause mah four-foot iron-pipe cheater bar ain’t a-gonna bend…
Minor nitpick: that’s a serpentine belt, the kind that drives rotating loads such as A/C compressor, alternator, power steering pump. A timing belt drives the camshaft(s) and is “cogged.”
Good catch!
With a bit of luck, I’ll never need another one…
I like your attachment better than mine — I cast an epoxy plug around a few ribs. But mine are actual timing belts, with crosswise cogs, not lateral. Better mechanical griptivity too. (It was your idea — thanks again! :) )
Epoxy: the universal solvent!
Wish I’d thought of that… [grin]