Winch Mount Testing and Breaking Rope

I decided that my home made winch mount IMG_3804needed to be tested so I could trust it somewhat. I see from some of the conversations I am not the only one with doubts. The mount performed perfectly, although he synthetic winch rope broke.

The tests were all done on the first layer of the drum to give maximum tension. This also places additional load on the mount due to the increased height adding leverage.

Test 1 – Drag Car on Dirt (Wheels Locked)- Passed

Test 2 – Drag Car on Dirt Up Hill (Wheels Locked) – Passed

Test 3 – Drag Car on Bitumen (Wheels Locked) – Passed

Test 4 – Drag 2 Cars Uphill on Dirt (Wheels Locked) – Rope Failed

I believe the rope failed due to 3 factors

  1. The Technora fibre is wearing noticeably more than the Amsteel Blue. I have read that the high temp materials are less abrasion resistant.
  2. The fairlead internal radius is too sharp compared to the external radius. The radius should be 4x the diameter of the rope.
  3. The fairlead sits approx 3/4 up the height of the winch, giving a fair bend to the rope as it goes over the fairlead and down the bottom of the drum. Rope rated at 13,700lb loses strength when bent. The tighter the radius, the greater the strength loss. The numbers are hard, as it depends on the diameter or the rope, and it’s construction. 12 Strand is a good construction for bending.

I am surprised a 9500lb winch can break a 13,700lb rope.

At no point did the mount appear to bend excessively, or sustain any visible damage. There was NO permanent twist.

The fairlead mount also suffered no damage, and the rope was spliced back together easily.

I was surprised at the amount of spring in the rope, you can see it coiled up under the tree where it ended up.

 IMG_3798 IMG_3799 IMG_3800 IMG_3802 IMG_3803 P8030027 P8030026

One thought on “Winch Mount Testing and Breaking Rope”

  1. A little disappointing result huh? A suggestion that if works would align things better. I’m guessing the alloy channel is bolted to the underside of the chassis rails. Turn the channel with winch upside down and bolt it to the top side of the chassis rails. That should align the rope spooling through the fairlead better. (I was going to suggest just turning the winch over, but that would surely twist the channel). Good work, and well documented. Cheers.

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