You are really cute Robert, and I love your expertise on these matters. This might be a bit brazen of me, but is there some way I can contact you privately? No harm in asking!
About 25 years ago, I took a statics and dynamics course in college. Barely passed, promptly left the engineering major and said, "Pointless knowledge I'll never use." Here I am 25 years later thinking, damn, wish I'd pay more attention at the time because this would be useful knowledge.
After watching this I got my bridle and soft shackles out and put them on the Colorado. After reacquainting myself with sine I calculated an angle of 25 degrees. Happy 😀
Good Info! I've used a bridle many times to reduce the forces on the recovery points. Never thought about how far apart they were and how they squeezed inward on the points. Will make sure to use a longer bridle to reduce the angles and forces.😢
Such a great video and breakdown of Bridles. This helped me a ton in determining my front end recovery modifications-- thank you for the math and physics breakdown. We made sure to give you credit and link this on our video.
Glad it helped! I watched your video - ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-YXszv97_lCI.html also agree with weight. You may want to check my Shackles video and spin yours 180 degress if you can to avoid side loading.
"''Life makes sense when U are educated" Excellent. i was always wondering for long time how long it should be and how is distributed the weight,force . ?? Thank u
Great explanation there Robert, back in the ‘70’s you would often see long bridles wrapped around Bullbars. The old Landrover Owners Club (Newcastle) had a module on this in their training courses, again back in the ‘70’s. There is also an element of “give” in a long bridle that can reduce the shock loading particularly in that off centre pull you mentioned.
Twin straps don't equalise the load unless it's a precisely parallel pull and the straps are the same length and in real 4x4 situations that will not be the case. If you have nothing else and with knowledge of that limitation it can work, but a single strap or rope is the way to go as shown. I hope the last slice of pizza was delivered with grace, garnished with apologies and accompanied by humble pie :-)
Looks like one of the X Lock uses is to slide on a bridle and then a soft shackle would connect it to a tow strap or winch line. It might have less friction than a sleeve sliding on the bridle. Any thoughts?
I haven't tried it yet but it should slide fine as the rope doesn't double back on itself just the smooth metal but might become more difficult with the desired smaller angle under load. It would be interesting to try the sleeve, X lock and pulley block in wet muddy conditions. I do agree that using as little metal as possible makes for safer conditions. Plus, I'd probably be using my X Lock and pulley blocks somewhere else in the system:)
Great stuff, an often overlooked point, Is amazingi how those forces build up. Just been out an d measured my points to check my bridle lengths. Thanks again.
Very useful for me as I was thinking about getting a bridle sorted. I just measured the distance between the points on my ‘23 Fortuner and they are 700 mm apart so will look for a strap about 4.1-4.5 based on your very helpful analysis
Another great presentation Robert, it's nice to find someone on RU-vid that knows what they are talking about. We use bridles when recovering vehicles onto transporters and trailers to help keep the winch rope central and not pull the vehicle side ways, especially if it has a wheel missing, the maths and science of it all is really interesting, after nearly forty years of vehicle accident recovery I'm learning something new, and I'm an IVR instructor, non of this is on the syllabus. Thanks again and take care 😀 Nige.
@@L2SFBC hi Robert, the IVR is the institute for vehicle recovery, and covers all aspects of recovery in a modular form, but we don't cover anything to do with off roading which is making really interesting watching, Many thanks 👍👍
Awesome Robert. Got my 5m bridle. Recovery points 770mm apart. My angle at straight line pull point is 18 degrees and the angles at recovery points are 81 degrees. All in a perfect world of course but neve like that on the track. Doing the best I can hey.
I try to bridle a single snatch block. Also. I always use 3 straps to create a bridle. By doing so. It allows for angles to reduce equalization towards load sharing. Such as 2 x 30ft straps with a 10ft center strap. For those without TABS. I UTILIZE 2 polyblend quad braided lines & wrapped 4-6 times, as points on sharps edges for bridles as well. Very forgiving. Some complain overkills And not worth the prep time. But doubt can kill. If I've learned anything. The suck always creates doubt on resistance.
This is a great explanation. I’m starting to pick up some gear to carry just in case and may plans will change as a result of this video. I definitely need another 20 ft. strap. My plan was to use a tree strap as a bridle if needed, but I think for many vehicles this would be too short. Something I hadn’t considered. Thanks for sharing! (I recently purchased a ranger and, while it’s not set up for serious off-road use like yours, I enjoy seeing your truck in action! Also planning to get rollers if I ever add a winch!)
I use the method of I Y T when i teach this. It also applies to your Tree Trunk protector end or anchor. It relates to the angle you make. I means Ideal Y means yes it will do. T means Terrible look for different way. It also applies to Abseil and climbing anchors.
@@L2SFBC Having said that, your videos are the most informative on RU-vid as to describe how the various forces are distributed when recovering in the real world. I have coined a new term: "The Pepper Maximum" which is the not to exceed bridle angle which for me is 30 degrees. Thank you for the time you put into your videos which should be mandatory before anyone attempts a recovery.
The force should be in N (Newtons) rather than kg. You did state that kg wasn’t technically correct. On the Forester the recovery points aren’t 1100m apart - I think you need to just add a subtitle correcting the audio comment to 1100mm.
@L2SFBC I realize that the video was posted 2 years ago. Very informative. I have a question on the bridle length. Is the length shown in the chart for each leg of the bridle or the entire length of both legs of the bridle? Thanks
Excellent video. your explanations and info were great. so with my 885mm recovery points, my 2.4m bridle is no where near to the 3.5 to 5.2m length you recommend. You have definitely educated me. Switching to using my 6m strap today. But I would be very interested in your comments (pros or cons?) of using a kinetic rope or snatch strap rather than a solid tow strap for a bridle. I have always used tow straps as a bridle myself.
The forces mentioned here are applicable to lifting and rigging guidelines. A spreader bar of appropriate length (and stiffness) for the vehicle recovery points and using two equal length short connecting straps would always be a better option than a single bridle. Further you failed to mention the WWL of the bridle rope being exceeded at higher angles
A spreader bar probably isn't all that practical for most situations especially since it's not going to act properly if you have an angle in the pull, And an angle is when the biggest issues exist, with a straight pull a spreader bar would work but at that point, you might as well carry a longer bridle. A better option would probably be a 3:1 pull where your first snatch block is on one anchor point and the end of your wire rope or synthetic rope is hooked into the other anchor point then the angles would be reduced and your pulling force would be increased if need be, Only problem is the sideways forces on the anchor points would still be a problem if they aren't strong enough to withstand that and you need to pull off to one side. And if you are worried about one anchor taking twice as much load with the 3:1 being as one anchor would have a 2:1 on it and the other would have a 1:1 then you could add another snatch block for a 4:1 and have a 2:1 for each anchor.
Great video, as are everyone’ of yours I’ve watched so far. Interesting how the laws of physics can be your friend with a snatch block in a pulley system, but gang up and kick your a### with a bridle. Just went out to my truck, 93 hilux and checked mine as I only have a 2m bridle, but as my recovery points are only 600mm apart this gives an angle of a shade over 17 degrees so all good. Used an on line calculator, wonder of google!
My recovery points are 533mm (21in) apart, so I reckon a 8ft bridle should have me around 20 degrees? I don't have one of those fancy protractors. lol Thx, Robert. These videos are awesome!!!!!
When by accident you discover a pot of gold ! Saved this clip for future reference as well as shared with others in an Off Roading community. @ 11.19 onwards, when the Recovery Point is 700 for a 30 degree angle it works to a minimum length of 3m. My question to this is what if I am not able to source a 3 m bridle but a shorter one say 2.5m. What would the impact be ? I admit I may have missed the answer in your clip....if you could point me to it, would be great....else, what would you recommend. Regards from India.
Nice info thanks again. I've always wondered how effective and what the purpose of using a bridle is. I think the big take away based on your summary is that the benefit is reducing the load on the points of the vehicle being recovered , not the overall load on the pulling vehicle . seems like this is best used when you're really really stuck..... I usually tell myself, the less parts being used in a recovery the better, so I don't often use this setup. ....I'm curious , what do you think of using a flat tree strap , like the green ARB you haber , as a bridle if needed ?
Question about a bridal: What is you used a snatch block at the vee of the bridal to permit the attached winch line or tow rope to move along the bridal with less friction? Seems like a good idea to me.
That actually is the correct way to have a "force equaliser": rigged, it also limits bend radius to more in line with "recommendations"..... (we would need load cell data to actually see what effect it will have 5% or 30% ??...) 4x4'ers have just gotten scared of using hardware - too many people snatching off substandard towballs and unrated tow points....
I would think that the metal introduced in this location (v of the bridle) would be of lessor concern (at least on the stuck vehicle side) than the benefits it would provide through less friction and more continuous load adjustment on the recovery points. Am I thinking about this correctly?
Hello Robert, I understand from your video that longer bridle length is better in all cases as it will keep the angle low. I am thinking that a 7 meter rope will do the trick in the majority of instances without putting undue stress on the system. My question is, if the recovery is going to be using a snatch rope, does the bridle need to be made of snatch rope as well? I am guessing the answer is yes, but want to make certain as I put my recovery kit together.
Could you comment on the use of a loop of webbing rather than a rope in the construction of the bridle? I typically run a rated static loop (12 meter) attached to bow shackles attached to rated recovery points . I keep the loop doubled to the tow rope or strap. I like the idea of using the static loops from the lifting industry because of their versatility as tree protectors and other uses as opposed to a dedicated tow bridle.
Would there be any benefit to using a recovery ring on the bridle? Comment: wish you had been my trig and geometry teacher. Your explanations are much easier to grasp using the methods you have employed would have had my attention. Thank you.
There would be a benefit as then the equalisation would be, well, easier when the pull changes direction. But, it'd be a pretty small benefit so no real need. Appreciate the comment, please share the video!
Fantastic video - thankyou. Been using bridles for 20 years but had no idea the side forces on the recovery points were as great as they are. So what's the next step? Should bridles should be getting longer (say 8-10 metres) and snatch straps should be shorter (say 5 metres). Secondly, if longer bridles were being used, should they be elastic like the snatch strap? Would an elastic snatch strap make a better bridle than an inelastic equaliser strap?
8m is gets into the law of diminishing returns for recovery points about 900mm apart. Don't need to be very elastic as the other rope can do that but a little elasticity is good to absorb loads.
I wouldn't be too concerned about the angle - e.g. if you just use the winch the angle is actually 180 degree, or close to (your anchor point - the winch - sits in the middle) and the crossbar / winch bar is - hopefully - designed that it can cope with the moment / torque caused by the pull from the middle via the winch. Now this moment / torque (force x lever where the lever is half of the winch bar width) will be always more stressful then the "clamping stress" (pressure) caused by the bridle. Saying this, the crucial points are - like it is the case for most recovery scenarios - the design of the recovery hooks / loops / lugs and how they are attached to the vehicle / crossbar / winch bar. Even when aftermarkets recovery hooks are fitted, and even if they are rated, the question is whether the way (welded, bolted, clamped), and the location, and the strength of the material they are fitted to, are fit for purpose. That is - IMHO - the most unknown parameter. And that is also the reason for me why snatching should be avoided at all times as there is no practical way to determine - especially not in a recovery situation - whether the recovery hook design is fit for purpose.
There will never be a 4x4 recovery where you have to get that far into it, All that matters is you stay within WLL for all equipment, you don't have any bridles at less than a 30-degree angle without considering the forces on it, You know the ratings and capabilities of whatever recovery points you attach to, etc. The only time you really have to get into the math and figure it out fairly precisely is when you are dealing with some very heavy shit and relatively low-rated rigging and winches compared to the load... I.E. when a 35-ton wrecker recoveries a 100,000-pound machine fully engulfed in mud. At that point, you are dealing with some relatively small rigging and winching capabilities and you really need to be precise with your math or you will break something and get people hurt. So if you are recovering your 4x4 with a rope and a bunch of tiny pullies, then maybe you need to focus on the angles and the math behind them, but with most people having 12,000-pound or close to it winches on their 4x4s it's not an issue.
This is interesting but are the maths correct? Taking your 170degree extreme example, the chart claims a 1,500kg force can be multiplied over 10x into a 17,145kg force. But hang on - if I attached the entire 1,500kg force to just one recovery point, at right angles (180degrees) then I would have 100% of the 1,500kg as the inward force. Not 10x that. I can't create more force than I have to start with.
I wonder about the suitability of synthetic winch rope for use as a bridle if Kinetic recovery is employed. I understand shock loading is not good for synthetic rope. Other than that very good & informative video as ever Robert. 😀👍🇬🇧
Something is bothering me about this. If I am putting 3000 "kg" (we all know it should be Nm) into the system, how can I be getting over 3000kg out of it? I think it is actually showing that to get any movement in the desired direction with a larger included angle in the bridle the recovery force has to increase to the point it exceeds the SWL of the gear. In particular the larger lateral force on the recovery points.
@@L2SFBC ah, thanks. I don't doubt the numbers, I think the explanation is incorrect. In the other video there is a force exerted through the rope from the bolt, which is added to the force exerted through the rope from the car. That force is equal to the force exerted by the car, otherwise the car would move. If there was no force from the bolt the car would fall down. Newton's Law. Try putting the scale between the bolt and a snatch block. It will read 470-500g as it did before.
Ok, so if the goal is to make the angle of the bridal as small as possible, why don't all off road vehicles just use a single clevis mount in the center of the vehicle?
Thanks for your measurement, testing and explanations. Very interesting. Besides the max load I am concerned about damage through asymmetric distribution of the load. How dangerous is snatching with only left or right recovery point for the ladder frame becoming a parallelogram rather than being a rectangle as it should be? I remember crunching sounds from the frame of my Jeep Wrangler JKU while snatching a bogged heavier Chevrolet Blazer out of a mudhole using only the left recovery point.
Ideally you want to spread the load, but it's hard to answer as it all depends - the force of the pull and the nature of the vehicle. Always reduce recovery load by digging etc or using ramps. However...this is more of a fear than a real problem.
From South Africa. Hi, I have a chart that indicates the force required to extract a mired vehicle. It considers depth mired / gradient / damage / ground condition / and all the inputs . Is there andigital chart / app. Showing basic rigging and force required as a guide / indication of the mechanical advantage ?
Very informative video - thanks! Wouldn’t it be kinder on the line to use a snatch ring at the bridle connection point and get the appropriate bend radius rather then webbing tube and rope to rope connection? Thinking of Sabre or Factor 55 shown in your snatch ring video.
Thanks - but If I am truly stuck, I’m likely to have a snatch block for a double pull so the metal will already be in the line. (13,000 GVW and a 16.5 winch). That said, if it makes little difference, I should look at the webbing.
Great video. I'm a beginner and I find your way of presenting very easy to follow. Can you recommend a place that sells 5m bridles? All I can find is 2.5/3m bridles.
Hi - have a synthetic rope maker custom-build one for you. They will need around 7-8m of rope to make a 5m rope. Use the thickest rope possible, say 18mm.
Just reviewing some videos since their premiere....if using a bridle and 2:1 pull, do you have to worry about abrasion from the winch line crossing the bridle? (I suspect the brindle sheathing would provide adequate protection.
I'm interested to know thoughts on using a 5500kg rated winch extension as a bridle? I have a kit that included one but I have added a dyneema 25m one to my kit and have 30m of dyneema on my winch as well, so the 10m one is a bit obsolete really, but I keep it in my kit anyway just in case a recovery requires an extension but not that far. I wondered since bridles arent readily available above 4 meters, so a 10m one not only reduces the angle significantly, but also acts as a 5m winch extension still while being used as a bridle/equaliser.
@L2SFBC I figured since the recovery points from roadsafe are rated to 5000kg per pair, (RPPAT-04) then a winch extension (no elasticity like kinetic straps and ropes) the 5500kg rated 10m winch extension would be pretty perfect for the job. And places like George 4x4 have them for sale at the moment for as little as $10 plus postage for a NATA tested strap. You can't really go wrong with that.
Hi. Very informative as usual. Like most people my bridle is too short. Looking around hard to find longer ones. Any quality brands you could recommend?
Hello Robert i have a question maybe you could demonstrate the answer? How much force would be required to pull a 5,000 lb jeep stuck in mud up to frame in thick sticky mud? Is it easily posable to exceed 10,000 (no hidden logs boulders ect.) Im trying to find a commen % of suction to add to a gvr when setting up recovery gear.
Hi - I'll be doing a video on such forces in due course. The short answer is about double the vehicle's weight, so yes could exceed 10,000lb. You can reduce the force required significantly by driving the wheels during recovery. And, definitely dig out to reduce forces, and use traction ramps if you can. What you describe is about worst-case scenario for load.
Thanks for the vid. I visited the Q&A and noticed that tree protecter strap can be used, however is it ok to use snatch strap or kinetic rope as well as bridle?
Hi Robert You have not considered what will happen if the vehicle is impeded by a rock or ledge in a rut and what happens if the vehicle is pulled on an angle
I went to my local tack shop and got a leather bridle... Oh, wait, we're not talking horses. Seriously, excellent info on the forces encountered during a recovery.
Pretty sure those shackles on the ranger are on the wrong way around, the pin should go through the recovery point not the shackle, now your pulling on the pin instead of the shackle itself.
@@L2SFBC I just came back from a training course and they swore this was the wrong way. I think this is a problem with the industry as a whole, you never really know if you are getting the right information (both guys over 25 years of experience and accredited trainers in Australia) The rear shackle for example that goes into the towbar made me think they were right as with that one you pull on the shackle not the pin. Also if you watch this video from rhonny dal another respected name in the industry, he shows the pins going in first, not the shackles: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-KcUDgmSMhWk.html&ab_channel=RonnyDahl
@@L2SFBC I will thank you. I've only been a short time a a part of the 4x4 club and I'm already sick of it. Everything is clear as mud and people are literally getting killed because of miss using equipment and ratings being badly missleading. Thanks for the reply anyway.
My recovery points are 770mm apart. I will go 5m 8T equalizer strap. About that for a 20 degrees mark of included angle in my case then. I purchased a shorter one last year I haven't used and after watching your video I am off to purchase a 5 metre 8T equaliser strap. Bloody brilliant technical information Robert.
Fantastic. A video where the maker understands trig. One other thing to remember is that a longer bridal reduces the size of the angle and reduces side loads on the recovery point. A shorter bridal will increase the lateral forces.
Awesome/Accurate info, but you just need a different presenter. It's so robotic that I am considering offing myself about 10 minutes into to any of these videos. It's like having that brilliant professor that just puts you to sleep.
