New CMI Pulley

[Crimsonking]

I’m not trying to spam, but I’m pretty excited about the new developments that are hitting all at once. Kris at CMI is a great guy and has worked with arborists to get their ideas to market. The latest is the purple hunk of aluminum posted to social yesterday. It is a 3Strand design, but I don’t have the insurance for rated gear, so we decided to make it a CMI product.

Now, waaaaaaaay back in the day, I ordered some of that thick skin @islandarb was selling on treebay. I still have some left from that order, so I want to hear y’all’s thoughts on the pulley!

 

[Jehinten]

First impressions, it looks robust, but the sheeve diameter looks a little small. Does the sheeve size affect its efficiency? What is the max rope diameter?

I imagine CMI is a great company to work with. I just contacted them this morning regarding my ropejack that I admitted to damaging by overloading it. They just said to ship it in for them to go over every part to ensure it's all good to use. Great customer service.

Congratulations again on your new ventures, and best of luck in your sales.

 

[Rope_goat]

I’m not trying to spam, but I’m pretty excited about the new developments that are hitting all at once. Kris at CMI is a great guy and has worked with arborists to get their ideas to market. The latest is the purple hunk of aluminum posted to social yesterday. It is a 3Strand design, but I don’t have the insurance for rated gear, so we decided to make it a CMI product.

Now, waaaaaaaay back in the day, I ordered some of that thick skin @islandarb was selling on treebay. I still have some left from that order, so I want to hear y’all’s thoughts on the pulley!

Dude, this looks amazing. I can’t wait for it to come out. It seems pretty intuitive. Do you guys have a name for it?????

 

[Crimsonking]

Ct

First impressions, it looks robust, but the sheeve diameter looks a little small. Does the sheeve size affect its efficiency? What is the max rope diameter?

I imagine CMI is a great company to work with. I just contacted them this morning regarding my ropejack that I admitted to damaging by overloading it. They just said to ship it in for them to go over every part to ensure it's all good to use. Great customer service.

Congratulations again on your new ventures, and best of luck in your sales.

The sheave was a grasp with reality- many of us have brainy discussions about bend radius, but then we have to get honest about how a ring to ring friction saver actually lines up- with one ring higher than the other. That means most of us climb mrs with the bend radius of a single ring. We won’t look at the fimblclimb. This isn’t throwing shade at those products, either. I just figured if I did better than that, it would be super good enough. Working with Petzl as a technical partner when I was training full-time opened my eyes to a good, nuanced view. I like Petzl’s take on reality vs ideals. Their manuals aren’t just filled with checks and x’s. They have icons that communicate hazard without restricting those scenarios. Petzl also released a friction saver with a pulley that has a similarly sized sheave as the new CMI pulley.

So yes, the diameter flies in the face of all the rules we learned, but I doubt it causes any more strength loss than a knot (Petzl’s logic behind their splices’ ratings, btw).

I hope my tone isn’t coming out defensive or strong, that’s not my intent. I understand the design is perhaps a bit rebellious, but not without purpose or careful consideration.

As for efficiency loss, I’m sure there is some compared to other pulleys on the market, but there’s give and take with any product, so I’m okay with that. Its competitors aren’t recommended for cinching to a tree, and they aren’t rated for two-person loads when anchored to the body of the pulley. When I use it in mrs, it’s worlds smoother than rings, and I can’t say I feel a big difference between it and other pulleys I’ve used, though I’m sure there is some.

I recommend normal climbing diameters- up to 13mm. And thanks for asking this- we’ll have it on the final product. An oversight, for sure.

I know someone is going to rig with it. That’s their risk, and not a recommendation at all. We might explore something for that when we see the market response to the first iteration.

We do have a name, but I am letting CMI take the lead with releasing it. Its nickname before finally settling on a real name was PPT- the pulley plate thing. Feel free to use that until CMI makes an official announcement.

 

[Stelzer]

Good luck with this. I was just saying today on another forum I admire this site and arb forums as a whole for their continuing innovation. I'm just a licensed GC who does primarily painting in the summer and xmas lights in the winter and rarely do any exciting new products come to market. This site in particular seems to foster innovation which benefits everyone. It's an impressive but rare dynamic. Kudos.

 

[Jehinten]

Ct

The sheave was a grasp with reality- many of us have brainy discussions about bend radius, but then we have to get honest about how a ring to ring friction saver actually lines up- with one ring higher than the other. That means most of us climb mrs with the bend radius of a single ring. We won’t look at the fimblclimb. This isn’t throwing shade at those products, either. I just figured if I did better than that, it would be super good enough. Working with Petzl as a technical partner when I was training full-time opened my eyes to a good, nuanced view. I like Petzl’s take on reality vs ideals. Their manuals aren’t just filled with checks and x’s. They have icons that communicate hazard without restricting those scenarios. Petzl also released a friction saver with a pulley that has a similarly sized sheave as the new CMI pulley.

So yes, the diameter flies in the face of all the rules we learned, but I doubt it causes any more strength loss than a knot (Petzl’s logic behind their splices’ ratings, btw).

I hope my tone isn’t coming out defensive or strong, that’s not my intent. I understand the design is perhaps a bit rebellious, but not without purpose or careful consideration.

As for efficiency loss, I’m sure there is some compared to other pulleys on the market, but there’s give and take with any product, so I’m okay with that. Its competitors aren’t recommended for cinching to a tree, and they aren’t rated for two-person loads when anchored to the body of the pulley. When I use it in mrs, it’s worlds smoother than rings, and I can’t say I feel a big difference between it and other pulleys I’ve used, though I’m sure there is some.

I recommend normal climbing diameters- up to 13mm. And thanks for asking this- we’ll have it on the final product. An oversight, for sure.

I know someone is going to rig with it. That’s their risk, and not a recommendation at all. We might explore something for that when we see the market response to the first iteration.

We do have a name, but I am letting CMI take the lead with releasing it. Its nickname before finally settling on a real name was PPT- the pulley plate thing. Feel free to use that until CMI makes an official announcement.

Thanks for that reply and not defensive at all. I haven't seen it on socials so this is the only look at that I've had. The robust design screamed rigging to me, hence the question in rope diameter and consideration of efficiency for higher loads. I personally only doubled rope climb on cranes and so a climbing pulley didn't cross my mind.


Another question, is the bottom becket considered a rated attachment, should someone want to incorporate a mechanical advantage system. It looks to have plenty of room for a carabiner attachment.

 

[treebing]

I love the look. What applications do you like to use it for? Like pulley saver? A ring and ring?

 

[Crimsonking]

Thanks for that reply and not defensive at all. I haven't seen it on socials so this is the only look at that I've had. The robust design screamed rigging to me, hence the question in rope diameter and consideration of efficiency for higher loads. I personally only doubled rope climb on cranes and so a climbing pulley didn't cross my mind.


Another question, is the bottom becket considered a rated attachment, should someone want to incorporate a mechanical advantage system. It looks to have plenty of room for a carabiner attachment.

Yes, it's rated. Since the pinto, releasing a non-rated becket feels taboo.

Most people who have put their hands on it have asked about rigging. I do want to doctor the design a bit for that in time. Larger sheave and a couple other adjustments.

 

[Crimsonking]

I love the look. What applications do you like to use it for? Like pulley saver? A ring and ring?

Thanks! My original intent was canopy anchor- flint locker with a roller. That said, I want all my tools to be multipurpose, so it can also be used in a pulley saver. In fact, I love the way the pulley changes the feel of my RRP in mrs vs rings. Just because I had it on hand, I've also used it as a connector between lines. Unnecessary, but why not.

 

[Brocky]

I like the lack of a bolt and nut, or spun rivets sticking out on the sides.

 

[Jonny]

 

[Crimsonking]

I like the lack of a bolt and nut, or spun rivets sticking out on the sides.

It was tricky. I love working with Cmi because Kris is willing to push their limits to make things happen. He doesn’t like saying no to a challenge, even if it’s beyond what the company has done in the past.

 

[Brocky]

Another plus for me is it’s not Notch green!

 

[evo]

Looks interesting.
My initial thoughts are that it’s only going to be good for a friction saver.
Personally I like a little friction smooth bark or rings. There could be a bunch of other uses but the sheeve gives me reservations. And not so much the sheeve but what my imagination says of the axle.

What are your thoughts on one big ass fixed axle with a thin stainless ‘tube’ with just enough flair to prevent rope fibers getting snagged? Essentially more of a roller than a pulley. Obviously it won’t be efficient but neither is the DMM pulley carabiner.

For hauling applications the becket could have a 3 hole rigging paw milled in. And or how about a milled tab 90 degrees to the pulley with a single carabiner hole? For hauling rigs it actually really helps to have the pulleys 90 degrees from each other aiding in mitigating rope rub eking out just a little more efficiency.

 

[evo]

Looks interesting.
My initial thoughts are that it’s only going to be good for a friction saver.
Personally I like a little friction smooth bark or rings. There could be a bunch of other uses but the sheeve gives me reservations. And not so much the sheeve but what my imagination says of the axle.

What are your thoughts on one big ass fixed axle with a thin stainless ‘tube’ with just enough flair to prevent rope fibers getting snagged? Essentially more of a roller than a pulley. Obviously it won’t be efficient but neither is the DMM pulley carabiner.

For hauling applications the becket could have a 3 hole rigging paw milled in. And or how about a milled tab 90 degrees to the pulley with a single carabiner hole? For hauling rigs it actually really helps to have the pulleys 90 degrees from each other aiding in mitigating rope rub eking out just a little more efficiency.

Actually everything I just said but make the side plates a smidge longer, have the axle center to the side plates. This would make the pulley reversible, a bigger benefit if one attachment is 90 to the other end. A similar design could have the 3 hole plate on one end.

 

[treebing]

Thanks! My original intent was canopy anchor- flint locker with a roller. That said, I want all my tools to be multipurpose, so it can also be used in a pulley saver. In fact, I love the way the pulley changes the feel of my RRP in mrs vs rings. Just because I had it on hand, I've also used it as a connector between lines. Unnecessary, but why not.

Can't wait to get one.

 

[Crimsonking]

Looks interesting.
My initial thoughts are that it’s only going to be good for a friction saver.
Personally I like a little friction smooth bark or rings. There could be a bunch of other uses but the sheeve gives me reservations. And not so much the sheeve but what my imagination says of the axle.

What are your thoughts on one big ass fixed axle with a thin stainless ‘tube’ with just enough flair to prevent rope fibers getting snagged? Essentially more of a roller than a pulley. Obviously it won’t be efficient but neither is the DMM pulley carabiner.

For hauling applications the becket could have a 3 hole rigging paw milled in. And or how about a milled tab 90 degrees to the pulley with a single carabiner hole? For hauling rigs it actually really helps to have the pulleys 90 degrees from each other aiding in mitigating rope rub eking out just a little more efficiency.

Thanks for your input, and to everyone else, too!

I’ve kicked around the idea of a rotated tab instead of the becket. We’ll see what happens.

The axle has an 8,000 lb mbs, and even if it failed (ummm, what they doing?) the line is captured inside the body with an mbs of 10.5k lbs. Unless someone rigs a top with a 5/8 line (please, no) the rope should break first. We have the option to upgrade the axle to get a higher mbs, but I didn’t see the point. If we do a rigging version, we have options for beefing up the numbers with small changes.

 

[evo]

Thanks for your input, and to everyone else, too!

I’ve kicked around the idea of a rotated tab instead of the becket. We’ll see what happens.

The axle has an 8,000 lb mbs, and even if it failed (ummm, what they doing?) the line is captured inside the body with an mbs of 10.5k lbs. Unless someone rigs a top with a 5/8 line (please, no) the rope should break first. We have the option to upgrade the axle to get a higher mbs, but I didn’t see the point. If we do a rigging version, we have options for beefing up the numbers with small changes.

I wonder how much strength the stiff leg above the hole adds. My biggest gripe with the rated becket of the pinto is its functionality, any hardware in there conflicts with the rope. The the thought of converting the becket to a more standard eye 90 degrees and slightly moving the axle more central would allow it to be flipped, giving the user options to avoid hardware conflict (and even bolt on a rope wrench!)

 

[Bart_]

Someone had fun on their mill and did some filing; ) Fun making those tiny really radiused groove pulleys too. : ) The pulley size carves out some middle ground - ring and ring worst (not measured), biner next worst, biner with tiny pulley not far behind, yours here, pinto pulley next, real pulley eg 4" pretty reasonable. Tree bark is near ring and ring and biner. You strike a balance between keeping normal DRT descent enabling friction and removing some DRT ascent piss-you-offing friction. I think that's a good functional niche.

 

[Crimsonking]

How are you able to articulate my head so well? Not even sure the thoughts themselves were that well formed.