Recovery Bridles (Equalising Straps) and understanding Sling Loads

At the request of others...

Recovery Bridle - A recovery bridle is a rope, cable or webbing strap attached to both sides of the vehicle being towed or winched. It allows for relative movement on the winch wire, tow rope or snatch strap to deflect from side to side allowing the towing vehicle and the vehicle being towed independence of movement

Equalising Strap (ES) versus Tree Trunk Protector (TTP) - An ES is specifically made for use as a bridle and is usually two layers of webbing sewn together with a wear protection sleeve for the area where the Snatch Strap is attached. A TTP is usually one length of webbing and often does not have the wear protection necessary for prolonged towing. TTP's can be used as bridles but some protection should be considered at the Snatch Strap attachement area.

My Recovery Bridle (or Equalising Strap if you prefer) is a short length of 25MM Dyneema Rope I have eye spliced myself with a breaking strain just short of a space shuttle launch

Here is one of the best I have ever seen and puts my home made jobbie to shame. Note the blue 'anti recoil' straps in case of a rigging component failure

Sling Load Angle is the angle the legs of the sling form against the direction of the applied force.

Many people assume that as soon as an ES or Bridle is introduced then the applied force is halved and transmitted equally to the attachment points IE 1000 KG from the Snatch Strap will be seen as 500 Kg at the left attachment point and 500 Kg at the right attachment point of the ES.

If the angle formed between the front of the vehicle and the legs of the strap is 60 degrees or more (as in the piccy above) this is true and a 1,000 Kg force will appear as 500 Kg's at each attachment point.

If the ES was shorter and the angle formed decreases to 45 degrees the the 1,000 Kg force will be seen as approx 700 Kg's at each attachment point... as the angle decreases the load increases and past 60 degrees is as much as 90 % or 900 Kg's

Now, this is all pretty heavy sh1t that is the life blood of riggers etc and hats off to 'em but I prefer a simpler life so I look at it this way...

Pretty much only two things can go wrong, either a) the sling angle goes pear shaped OR b) one leg lets go and everything else stays attached. In either case the Max Load on an attachment point is now the recovery force (1,000 Kg in our example) so I rig it that way and pretend the bridle is of no assistance in sharing the load whatever

Remember the original definition and purpose of the Recovery Bridle
"allows for relative movement on the winch wire, tow rope or snatch strap to deflect from side to side allowing the towing vehicle and the vehicle being towed independence of movement"
The fact that it also has the side effect of reducing the load at the attachment points should not necessarily be relied upon

I look to the bridle to apply some of the winching or snatching force to both chassis rails, rather than one.

I almost want to get stuck now ;-) After looking at the dissy wiring to answer Evil's post I hooked up my 2.5m equaliser/bridle to the new hooks on my new recovery plates. Nice narrow angle and it even loops nicely around the bullbar without obstructing number plate or lights. There is room for improvement - the wear sleeve is actually a red plastic flag looking thing. Supercheap..... Will need to do something about that. the bridle itself and the stitching look ok. Plan to give it a test on the neighbour's mango tree. too chicken to give it a work out on a telly pole. If it fails the mango tree will cop it, and hopefully produce more fruit :-) The mango tree is a good and faithful assistant. It and a chain and judicious use of low range helped reshape the barn door after spouse backed into a post. Now to be fair, I have also backed into a post. However I was lucky enough to dead centre it with the tow bar, not the spare wheel :-)

Good informative Post Thanks

Hey ET.

Where do you buy that bridle from in WA?

Rossco

I recently saw a 10mm dynamic bridle recovery kit with shackels and all for $102 in Outback 4WD in Bayswater, VIC - not that it helps you Rossco, sorry mate.

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Originally Posted by DX grunt

Hey ET.

Where do you buy that bridle from in WA?

Rossco

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It is made right here in WA, Roscoe (a real honker isn't it).

The 4WD recovery kit they produce is the absolute Bees Knees, wish I'd found 'em before I got all my gear... altho I might be tempted to get a kit and sell off most of my stuff

They look after the Mining Industry and make Snatch Straps, Bridles etc and Recovery Kits for vehicles up to 100 tonnes

I am trying to get a sample along to a club night ( of the Patrol Kit not the 100 tonner but bringing one along for a giggle would be hilarious)... I'll keep you posted. Will know more directly after Easter

I know this is an old old old thread but I want that bridal strap. What brand and where do I get one?

Still waiting for answer?

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Originally Posted by Shaun 4x4

Still waiting for answer?

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ET has had a few things on his plate lately so hasn't been on much, if at all. You'll be better off maybe sending him a PM as these threads also get buried quickly

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Originally Posted by Clunk

ET has had a few things on his plate lately so hasn't been on much, if at all. You'll be better off maybe sending him a PM as these threads also get buried quickly

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Thanks for the reply.
Yer i sent him one a month ago or so. But no reply.
I just want one they look like the best bridal strap ive ever seen.

I have found snatch straps with anti recoil straps now which ill be ordering very soon.

Well written mate and spot on.
As you said the pi you posted is a perfect setup. We can't always have perfect but if you get a 3-4m ES or rope and a sleeve it will be the best option.
But remember the shackles. Ensure you always use the correctly rates shackles for the job.

hi Shaun ask at your 4x4 shop they may stock them, as they are used more now with all the IFS 4x4 on the road,
I designed a snatchem strap with that extra recoil strap about 6 years ago I think. Anyway if your local 4x4 shop
don't stock them go to your Cable and sling shop, they will know what your talking about

A good cable sling shop may even make one up for you out of SWR

I don't get why th op wouldn't give the name of who makes them.

BUT after a lot of searching...... I found them :)

http://www.comsew.com.au/?page_id=59

Its a common item now most 4x4 shops should stock them

I will have a look. The only 4x4 shops close to me are arb endorsed shops. So doubt they will have them

I would imagine they would.
good luck

Yeah at a price to match too.

http://www.supercheapauto.com.au/onl...d=218850#Cross

I have one of these

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Originally Posted by meh

http://www.supercheapauto.com.au/onl...d=218850#Cross

I have one of these

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I have the same. Have used it once and the 8T snatch strap snapped on first go. The bridle held up well apart from the crappy red plastic strap protector took a good beating.

Breaking an 8t strap tells me something was wrong, but not knowing scenario I can only guess.

@ meh good price for a strap to throw in your recovery box,

How does everyone else store their gear in a canvas bag or small Space case???
I use a purpose built box

I got on sale a full recovery kit for $100. Come in a canvas zip up bag, 2 shackles, snatch, winch extension, equaliser strap, trunk protector and a snatch block.

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Originally Posted by threedogs

Breaking an 8t strap tells me something was wrong, but not knowing scenario I can only guess.

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It was a brand new strap too. But I knew it was going to break just by looking at it. And first tug and it broke. I can't remember the brand but it came in a green canvas bag with gloves, shackles and a few other bits.

Any Chinese strap should be looked at, all Chinese lifting slings have been withdrawn at work as they have been made without the internal webbing that makes them strong and lift to the SWL , im assuming these straps will be manufactured by the same people who make lifting slings.