I have used synthetic line in my winch for years. Broke it the first time I plowed, re-tied it and haven't had a problem since.....This year I saw the post using a length of strap to take the weight off the rope. I have 3ft of 1 1/2 inch strap from Farm and Fleet with a plastic buckle at the plow frame end to make a loop. The other end is spooled up on the winch. Roller fairlead that came new with the synthetic rope. Once you get the strap wrapped a few times, the weight is off the rope. I haven't plowed with it yet but in the shop it seems to be holding the weight. Expecting snow again next week so maybe I will have a chance to test it.
Can't figure why your strap tore unless there was something on the roller that caused damage to the strap.
2001 Magnum 325 with a blown engine; rebuilt 2004. Broke timeing chain 2016 rebuilt again and still running. Warn winch and Moose 60" plow
2007 Sportsman 500 EFI, Polaris Winch, 26" Bear Claw HTRs on Moose 427x Wheels. 12x7 front, 12x8 rear, QSC Clutch Kit
My Trail Machine:
2004 Sportsman 600 Twin, 25" RipSaw Tires on stock steel wheels, Moose rear box
Completed Project machine:
2001 Magnum 325 MOSE with a blown engine. Transplanted a 2005 Magnum 330 engine. Committed suicide on the trail Oct 2016. Spun Rod Bearing after oild cooler line failure. Rebuilding Engine.