Pulley sheeve size

Mesquite

Mesquite

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Jan 22, 2022
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I have been looking at pulleys lately, since I'm in the market for some. I noticed 1.1 and 1.5 inch sheeves are fairly close priced. What I'm wondering is does the bigger size of 1.5 warrant the extra money and is it worth it? Or should I get an even bigger size two? Or 2.6? I probably won't be doing too heavy of work.
I have my eye on some rock Exoticas and a pinto rig

What pulley do you have?
What pulley is your favorite?
What pulleys do you hate?
 
OmniBlocks are nice for most rigging you’d do with 1/2” rope. I got a 1.5” and a 2.6 Material Handler which is rated in pounds force the orange 2.6” is rated in kilo newtons which is also a measurement of force rather than weight… pretty sure they’re the same only one is red and one is orange.

The name OmniBlock is kinda misleading in the arb world. I’d never expose these things to the dynamic forces I’d put on a real arborist block or rigging ring. Consider them a little beefier than your average rescue pulley, static loads only. There’s not much sense shock loading swivels anyways. Worth mentioning I think.
 
True favorite is an old school used gimmee , heavy duty 2 Ton w Swivel. Probably heavier than most people want to climb with but I don't care ... do the bulk of my lowering and even GRCS hoisting with it , runs on a Bearing
 
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  • #7
Im planning on using the pinto for climbing and also wanting to get a pulley with the pivoting side plates too, like a hitch tending pulley. the other bigger pulleys are for rigging. I currently dont need anything to big. very little negative rigging. Fortunately most tree i have worked have not be to close to houses and very few targets that couldnt be moved. But i have been practicing with all my cuts, for when that time comes and when those skills are needed. When there could be the possibility of damages i take small pieces.

You can look at it this way i have very few tools in this trade and as the more money i make the more tools im going to buy. Im doing my homework on pulleys because those are going to be my next purchase. Im thinking two pulleys for climbing and two pulleys for riggings. Im going to and have been using shackles like rigging rings. But i would like a couple of pulleys as well to be able to get more creative with my rigging like redirect into other parts of the tree or to other trees completely. So i can get more compression out of the anchor point and stuff like that

Pinto rig pulleys are probably strong enough for my needs but i like the built in swivels of the rock exoticas. And the main question of the thread is, how much does sheave size affect how they work in the real world?

I understand what you are saying jonny, and as it looks the red and orange ones are the same except a $30 price difference and the metric or imperial weight scale like you said.

I also plan on getting a impact block. I dont think i need it right away cuz i dont do alot of wild and crazy shock loads. Most of my pieces either run or are tied tightly off and dont fall far if any.
 
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  • #8
Atlissimus could you please provide a link to the type of pulley you are talking about? There are so many different pulleys google brings up when i search that.

Thank you for the input
 
People seem really happy with the Pinto for climbing purposes, in a false crotch/ friction saver setup or hitch tender. I got a Pinto and Pinto Rig for 5/8” rope and when I saw they were marked with 50Kn, I assumed they were meant for rigging, so never tried climbing on one.
Truth be told, aside from tending hitches, you’ll probably never see me climbing on pulleys. That zero friction at the tie in point doesn’t disappear, it just moves somewhere else in the system, like at the hitch.
A couple DMM or ISC rings on a friction saver are good enough for me if I want a false crotch for climbing.
With SRT it’s almost always a natural crotch anyways.
 
I like those small fixed sheaves climbing , have one below the HH , on longer spike free ascents another one above me hanging off the ascender
 
I've been getting good mileage from my cmi pulleys. Not sure they're the best choice to climb with due to weight, but they're fairly inexpensive, and good for redirects, or mechanical advantage systems, eg pulling.

Pro Traxion

www.wesspur.com www.wesspur.com
 
I have several CMI pulleys too, I’m very happy with everything I got from them. Not fancy, they don’t make stuff as pretty as DMM, but the prices reflect that, and it’s reliable bomber American made gear.
Their blocks are virtually indestructible.
 
Mesquite said:
And the main question of the thread is, how much does sheave size affect how they work in the real world?
Click to expand...
Basically, the bigger the sheave, the gentler on the rope and the easier to turn (lever arm vs friction).

For climbing, the load is very low, so the rope can take a small radius sheave without problem. Even just a biner can do it in a friction saver. Downside, the sharp turn induces a lot of movements between the fibers and this means internal wear.
For rigging, the load can be way more serious. The sheave should have a minimal diameter to limite the loss of the rope's rating and the wear. The rope just straight has its nominal rating strength, but when you bend it, it looses a certain percentage of its strength (unequal tensionning in the fibers bundles). The fibers move more, the friction and the heat both rize. That goes from barely noticeable for a very wide radius, to an unacceptable loss for a tight turn. It's an industry practice strictly followed and regulated for all the cable machineries, (crane, elevator, winch ...). I recall maybe 8x rope's diameter cuts down the rope's strength by 10% (don't take it for granted). Most of the arborist rigging blocks are about 5x the rope's diameter and that brings a 15% loss. I have to find the chart again to be sure of the numbers.

So, be gentle to your ropes and give them a big hug sheave.:)
 
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  • #17
Thank you for all the inside scoop.

Do you think a having a couple of pulleys with a swivel is necessary or at least helpful? Or does the line that the pulleys attached to allow the pulley to orientate accordingly to how it's needed to in the rigging system?
 
No swivels in my rigging.
Get at least one arborist block, the one with the attachment point that needs a sling installed directly. I have bent pulleys at the attachment point where the sling is clipped in with a biner.
 
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  • #24
Wow that cmi block! I can't afford to not buy it at that price point. Is the 2 tons thewll? Even thought its bigger than what I will need alot of the time, I can still use it for smaller stuff or redirects.

I'm still torn between getting a pinto rig with spacer or a rock exotica omni block.

How would a omni block double sheave work with only one rope? For rigging? I like the idea of getting two omni double sheaves for a mechanical advantage system and then if I need a pulley for a more complex rigging system I'm good.

But in the other hand i could just use riggin rings for everything.
 
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