pulling force of a B2920

[tractchores]

As I read about losing strength when tying a knot I was wondering - how do you guys attach ropes to the tree to be pulled. With Chain or a tow strap I just loop around and clamp back onto the chain or strap. Can this be done with an eye and a D clip or something similar, or do you use straps on the end to avoid the rope having sheer applied to it?

 

[Gary Fowler]

I did drawbar pull tests a while ago using a hyd cylinder with a pressure gauge. Test was done on damp grass. My 4x4 pickup with all season tires weighs close to 5000# and pulled 3500# when the wheels spun. My 2wd tractor with R1's weighs 6000# with loader and pulled 5250# when it spun. I had the 3ph at 18" off the ground to transfer weight to the rear. The truck tires just spun on the grass, the tractor kicked the sod out the back.

I set up my video camera looking at the gauge to capture the max reading.

I don't think that relates to actual pulling force. Producing 5000 # of hydraulic pressure on a gauge is not indicative of pulling force. It has to be factored in to show size of ram that you are pulling against. Inversely a 2200 PSI hydraulic pressure on a ram with 4 square inches of surface area should produce 8800 pounds of lift force.

 

[arrow]

As I read about losing strength when tying a knot I was wondering - how do you guys attach ropes to the tree to be pulled. With Chain or a tow strap I just loop around and clamp back onto the chain or strap. Can this be done with an eye and a D clip or something similar, or do you use straps on the end to avoid the rope having sheer applied to it?

We just threaded it back through as you do now. Key word here is "guiding." A 200 lb man can pull over a tree to direct a fall if the rope is 2/3rds up the tree so forces should be nominal to do this. Anything else is completely dangerous. When a tree had to be pulled opposite its natural fall line, we attached the skidder cable to it. Otherwise we climbed and topped it if a ground structure was involved.

 

[s219]

As I read about losing strength when tying a knot I was wondering - how do you guys attach ropes to the tree to be pulled. With Chain or a tow strap I just loop around and clamp back onto the chain or strap. Can this be done with an eye and a D clip or something similar, or do you use straps on the end to avoid the rope having sheer applied to it?

I use a tow strap or a tree sling. There are some tree slings that are a loop which can be used in several ways with varying strength ratings. This is the one I have: Endless Loop Polyester Round Slings for Tree Work

I'd never use a rope directly on the tree if you can help it.

 

[arrow]

I]

I'd never use a rope directly on the tree if you can help it.

Why not? We did it for 30 years professionally w/o a mishap. Again, what needs to be reiterated here is that one should not rely on a rope, chain, strap or any other conveyance to force a tree fall. It is a guidance procedure only. The only time we used slings is when we were up in a tree delimbing it to prevent branch fall. If one thinks to be on a tractor with a line of any material attached to a tree to create a forced directional fall and stem placement is critical (such as: I don't want to hit the house), please re-think that.

 

[s219]

I don't use my good long rope directly on the tree, except in specific cases, because you will wear the end of your rope little by little, and eventually shorten its useful length. That might seem trivial, but I count on having all 150 feet of my *only* bull rope and don't want to be cutting off 4 feet here or 6 feet there because tree bark frayed up the jacket or something else happened. On the other hand, chains, slings, chokers, and tow straps take a lot of abuse and won't compromise the rope if they experience wear and tear.

Sure, rope probably costs less per foot than the slings and tow straps, but if you have to cut enough off the end of your only long bull rope, suddenly it's not as useful anymore, and the remaining length has less utility value.

I'd have no problem making a disposable sling or choker from rope and using that on trees, knowing I can replace that at any time. I just think it's good practice to not use your long lengths of good rope directly on the tree.

 

[arrow]

I don't use my good long rope directly on the tree, except in specific cases, because you will wear the end of your rope little by little, and eventually shorten its useful length. That might seem trivial, but I count on having all 150 feet of my *only* bull rope and don't want to be cutting off 4 feet here or 6 feet there because tree bark frayed up the jacket or something else happened. On the other hand, chains, slings, chokers, and tow straps take a lot of abuse and won't compromise the rope if they experience wear and tear.

Sure, rope probably costs less per foot than the slings and tow straps, but if you have to cut enough off the end of your only long bull rope, suddenly it's not as useful anymore, and the remaining length has less utility value.

I'd have no problem making a disposable sling or choker from rope and using that on trees, knowing I can replace that at any time. I just think it's good practice to not use your long lengths of good rope directly on the tree.

There are little whip end covers for that (or there used to be) We dipped the ends of our ropes in that canned plastic crap. Prior to that stuff ropes were actually "whipped" with nylon thread. Our ropes lasted for years under heavy usage. They had good abrasion resistance as they were rock climbing ropes. I suppose outlook is everything. To me, the rope was just another expendable being paid for with jobs. To the homeowner, things fall under sort of a more sacred ownership that manifests itself by the initial expenditure which can be hefty for specialized stuff.

 

[s219]

Actually, I picked up the habit from doing tree work as a part time job when I was a teen -- the boss was a real stickler for taking care of ropes since lives could depend on them -- he had many stories of people getting hurt/killed by broke ropes, etc (picture a grizzled old Navy man turned lumberjack). But it really hit home, due to cost, when I had to start buying my own stuff. The outlay for my most recent bull rope was about $300 if I remember right.

 

[arrow]

On my last day on the job almost 20 years ago, I was given a 100' length of black nylon rope. I still use that rope today because maybe I've used it 10 times in the last 20 years. Sacrilegious I know but the ends are burnt whipped.

 

[tractchores]

Thanks everyone for the advice. I used the rope and pulley yesterday to both assist in felling and in one case pulling over a tree. The rope was great and while i didn't test it to the max it held up fine. The tree i pulled over was about a foot at the base, but cut so there was 4" left holding it. Pulled it over no problem.