Heat is also bad for rock climbing soft gear but we have ropes sliding on metal all over the place without significant heat buildup, we rarely use pulleys (really only for setting up mechanical advantage for hauling). I'm extremely skeptical that this puts any appreciable amount of heat into any section of winch line. Perhaps worth emailing them though and see if they can give you any hard test results.
1) Climbing loads are MUCH lower than vehicle winching. That's why. Most climbing rigging never need to be rated past 25kN (while not directly comparable to weight, about 5,600 lbs rated) or hold loads over a few hundred pounds. Often you use a 10:1 safety factor to hold a human overhead. We use higher loads and lover (3:1 or 5:1) safety factors for horizontal movement.
2) Why use a system that adds any heat to a heat sensitive line? Zero benefit to these rings. If you tell me that its because they are lighter, go weigh your truck.
For a normal pulley block setup I'd have to agree, these always felt little off to me. Like this setup:
But if you just need to alter the winch line path a little bit, this one doesn't look so bad:
But then again why not just run the line through the bow shackle.
I dunno.
Bow shackles have even less surface area and will focus more heat.
Drat. I just bought two of these. The local shop told me they were better than snatch blocks for synthetic line.
Return them. Serious. The shop is wrong. Rings are not better, just different. All the evidence is against "better". Its just marketing. People will say "they're fine" - sure, probably most of the time, but why start with equipment you are making excuses for.
The ARB 20,000 LB pulley block is a very good one for our sized trucks. A jeep or mini-truck could be ok with a 15,000, but better to have more margin with a 20,000. Master Pull is good. Safe Xtract is great and mostly overkill for us. Don't buy on Amazon.
Will a ring mostly work? Probably. But why use a lesser practice when the best practice is easy to obtain? To save 4 lbs in your 5-7,000 lb truck? If heat does fail a rope it will be under that time when you have the highest load because you are in the sketchiest situation. And we have not even talked about failure to retain the rope under slack condition.
Also, you will be going against at least one rope manufacturer's recommendation. The
following information is from the manufacturer of Amsteel Blue, one of the best and most common ropes. Amsteel is HMPE. Critical temp is 150F. "
High temperatures can be generated when ... running them over stuck or non-rolling sheaves or rollers." That means don't run synthetics over non rolling sheaves. A ring is a sheave. A pully spins on an axle. A ring does not harm winch rope when the ring rotates. Using rotating rings the heat is generated against the soft shackle going through the hole. Still bad and wholly unnecessary. We don't know the actual heat tolerance of "Amazon" and off brand ropes. (use link above or Google "Samson Rope Warning Insert")
