Tombie doesn't this photo have the pin bind issue that we are talking about (orientation is good)?
http://www.overland.co.za/Recovery_G...terbach_01.jpg
All of the Philco, Arb etc type of fittings, orient the shackle pin horizontally and IMHO are a flawed design.
As an aside if the LUKE straps had a longer loop you could hitch it around your recovery strap loop (or bridle loop if you use one) prior to install and do away with those shackles that can turn into missiles.
With regards to the LUKE Strap, Clubgreenie why couldn't they just put some more meat/steel where the red is on your cad drawing, even thicken or double up the plate thickness and thicken the strap if necessary, once their physical properties are increased in size enough, the LUKE Strap will eventually be a strong enough connection, as long as they are mounted to the chassis adequately.
https://www.aulro.com/afvb/images/im...015/04/410.jpg
It has none of the orientation issues compared to the other recovery point systems, is a much easier recovery point system to install, could be left in the toolkit until needed, does away with the traditional shackle so is safer, doesn't damage the bodywork, connection to the bridle could be out in front of the car if the loops were longer, is 1/8th the cost of traditional recovery points AND it comes in 11 different colours:
http://www.corbeau-seats.com/towstrap
Straps lose their strength / rating as the radius of the material they are around decreased (radius decrease).Quote:
Originally Posted by Islandnomad
Straps also lose strength as they get wet, and any grit or dirt trapped in there abrades the webbing reducing its strength.
They still damage body work (as the snatch recovery will rip the strap up into whatever is in alignment with the 2 recovery points)
They will suffer from UV, Heat, Abrasion damage.
The shackle really isn't the risk (its less likely to break) - Mounting points are a thin chassis section ;), the strap is attached by single point/bolt and contains a lovely ballistic piece of metal..
They are cheap because their design is cheap, material is cheap and their use is as a light weight (race car) tow point
I'm not trying to be a smart arse about this. I'm just looking for a decent recovery point for my vehicle as they vary from $200- $400 each depending on the design, plus installation and none of them work particularly well, and most are pretty agricultural looking.
1. "Straps lose their strength / rating as the radius of the material they are around decreased (radius decrease)". Well increase the webbing thickness then??? Its an engineering issue, whatever the engineers recommend.
2. "Straps also lose strength as they get wet, and any grit or dirt trapped in there abrades the webbing reducing its strength". Keep them in the toolkit like the snatch strap and attach when required, keep them clean then.
3. "They still damage body work (as the snatch recovery will rip the strap up into whatever is in alignment with the 2 recovery points)". Yes depends where they are installed I agree, it's design does not negate thoughtful competent installation.
4. They will suffer from UV, Heat, Abrasion damage. Yes just the same as a snatch strap, they need to be in good nick.
5. The shackle really isn't the risk (its less likely to break) - Mounting points are a thin chassis section ;), the strap is attached by single point/bolt and contains a lovely ballistic piece of metal.. Most recovery systems contain a lovely ballistic piece of metal, if it were thickened up it would be fine, again whatever the engineers recommend.
6. They are cheap because their design is cheap, material is cheap and their use is as a light weight (race car) tow point. Maybe this exact recovery point should be strengthened a bit, that's an engineering issue that could be fixed. If this was done, I think this could be a much better solution than anything else on the market, sheer luck that its cheaper.
1. "Straps lose their strength / rating as the radius of the material they are around decreased (radius decrease)". Well increase the webbing thickness then??? Its an engineering issue, whatever the engineers recommend. Engineers do not recommend. They design to spec. If they recommended then they are liable, they design, just as I have, to a requirement, and FEA and destruction test. When passed all liability passes to owner of the design, installer and end user.
2. "Straps also lose strength as they get wet, and any grit or dirt trapped in there abrades the webbing reducing its strength". Keep them in the toolkit like the snatch strap and attach when required, keep them clean then. Yeah, you've clearly never traveled in serious mud, where you keep the winch rope unrolled and on the passenger seat so you don't have to be waist deep in water and mud to get it out and also have the bridle, tow or snatch strap attached and slung up on the bar, front and rear.
3. "They still damage body work (as the snatch recovery will rip the strap up into whatever is in alignment with the 2 recovery points)". Yes depends where they are installed I agree, it's design does not negate thoughtful competent installation. Without removal of the OEM bar it will always cause damage, with any other bar fitted, if fitted to the bar chassis mounts I would be concerned about the bar damaging the webbing.
4. They will suffer from UV, Heat, Abrasion damage. Yes just the same as a snatch strap, they need to be in good nick. Smartest thing you've said all thread.
5. The shackle really isn't the risk (its less likely to break) - Mounting points are a thin chassis section ;), the strap is attached by single point/bolt and contains a lovely ballistic piece of metal.. Most recovery systems contain a lovely ballistic piece of metal, if it were thickened up it would be fine, again whatever the engineers recommend. Again, they don't recommend...And of course they don't recommend, they engineer to a purpose. In this case recovery of a sub 2000kg vehicle without any consideration for slope, suction or other factors.
6. They are cheap because their design is cheap, material is cheap and their use is as a light weight (race car) tow point. Maybe this exact recovery point should be strengthened a bit, that's an engineering issue that could be fixed. If this was done, I think this could be a much better solution than anything else on the market, sheer luck that its cheaper. It would be better IF it had two attachment points, the webbing wasn't susceptible to water (immediately weakens it), dirt and mud (gets in and abrades it, most incidious because you can't see it) and UV (only potentially noticeable if the color was faded and correlated to UV damage).
I contacted the seller who was both amused and confused about my concern. So I sent the following in reply to:
Again note, tested by MSA (who are part of the RAC, basically a Motorsport oriented offshoot of the NRMA) There is no information about how they are tested, apart from I found a BS for tow points for motor vehicles, which is how I drew the previous conclusion on how they were tested. This applies in writing to solid metallic based points, I have worked on an assumption that this has been applied to the Luke points as the MSA has no testing facilities and they are a motoring organisation at the end of the day and it's the most likely source, ESPECIALLY considering the end use (NOT off road). But basically what you are looking at is a product the NRMA has said is ok for towing a vehicle and using it for off road recovery.Quote:
I'm a little confused as to what information you require from ourselves.
Our supplier has told us that these are tested by and certified compliant by the MSA (Motor Sports Association) up to 5000kg. You would have to contact them for the results of their tests.
Again I attached the images and detailed more,
Quote:
The problem is.
Motorsports applications are static, rolling cars, maybe a sand trap at worst. These really are designed purely just for towing. NOT recovery. You guys are selling to and actively marketing at off road users. That thing with a snatch strap which puts min 3 x load though it. I ran a cad and catastrophic failure occurs at 6400kg. Same level as a 12,000lb winch. And thats without adding suction from mud, slope etc. Add to the webbing loosing strength when wet, dirt gets into the fibres and weakens the structure.
People die using the wrong gear for recovery. I strongly urge you to simply rework the advertising to read only for use as a tow strap. Not for off road recovery.
Luke are a great supplier, I've used their (and others) harnesses for racing for decades but this has been tested by a motorsports assoc. What they know about the forces involved in a serious mud based off road recovery the kellogs monkey could teach.
Attached are three images, one of the basic design.
First image, 18_18_39. I've been generous and said it's 3mm HT steel. It looks like a generic seatbelt end. Programmed a grade 10.8 HT bolt as the anchor and applied a 5000kg load.
Second image, 18_20_22, shows side view of deformation at 5000kg. Deformation is plastic meaning permanent stretch, of 9.534mm.
Third Image, 18_20_19 is another view of above.
Fourth image, 18_16_56 is extreme loading at 90degrees.
This all comes about because on our local forum (aulro.com) the question was asked "How about these, they're way cheaper than the locally made (correctly rated) product (you could buy 8 straps for a pair of recover points) What do the recovery guru's think?"
Well we told him and told him and even after presenting him with the same data he still thinks we're out to get him and despite 8 people, having no association with, still thinks we're out to sell the rated points. Now I hate this litigeous society as much as anyone with common sense (if someone doesn't listed and dies well thats just Darwin's revenge). But unfortunately the legal system (and here in Aust it has and will happen). Someone will buy this product, get hurt or die and then they'll sue because it says "Ideal for off road" & "or just a bit of off roading fun for when we get stuck in the mud".
Please, ask the manufacture if they approve them for dynamic and off road winch or snatch recovery.
There's a reason they cost, engineering is not cheap. The work I did, design and FEA if from scratch, engineering to a requirement of 5000kg tow point would set you back $300- to $400/hr. Post design assessment of results std $250/hr (which I had done by two others).
Thats thing has taken a known piece of steel, a seat belt end, with a 12.7mm (1/2") hole that would normally take a specialised shoulder bolt, low profile head, shoulder 12.7mm to allow it to rotate for comfort and a 9.53mm (3/8") thread. It would be rated for 5000kg, given that there's a lot of seatbelt, and that webbing alone also is designed to stretch and absorb. There's very little webbing for shock absorption in that when you consider the entire sewn area is no longer a stretch point.
Firstly, of course you can just add away, but then you add cost, complexity of manufacture (thicker material needs to be drilled/laser/gas cut and then finished rather than punched). The webbing available doesn't get thicker, it gets wider (next size up is 3") which is F1/WEC/WRC spec, basically top echelon motorsport harness webbing. These in typical use have a 5 year lilfespan, and that's when they don't get wet, muddy etc. I only ever use this spec of harness even at club level as while they cost at least twice the price ($1200 + eace for a 6 point) they are far more comfortable, both in use and in crash and cause less soft tissue injury in the event of a crash. Put it this way, they are removed and returned for manufacturer inspection after every race. Regardless of weather, crash or any other event. This webbing is still susceptible to weakening by water, abrasion by dirt. And it would not be a lesser rate because "it's bigger and takes longer". More area, more dirt, same abrasion rate.Quote:
With regards to the LUKE Strap, Clubgreenie why couldn't they just put some more meat/steel where the red is on your cad drawing, even thicken or double up the plate thickness and thicken the strap if necessary, once their physical properties are increased in size enough, the LUKE Strap will eventually be a strong enough connection, as long as they are mounted to the chassis adequately.
Good luck getting them apart. The std practice of looping eyes is to put something (solid, ie: metal or wood) in between = missile. usually dome when you don't have a shackle. Also the crushing of the webbing from it's designed flat or folded/sewn form weakens it. Just as a rope becomes weaker at a knot.Quote:
As an aside if the LUKE straps had a longer loop you could hitch it around your recovery strap loop (or bridle loop if you use one) prior to install and do away with those shackles that can turn into missiles.
While the shackles will turn in they will not sit pin vertical, the body of the shackle will load against the underside of the chassis, and the bridle will load one side of the bow. And again there's only one bolt.Quote:
Tombie doesn't this photo have the pin bind issue that we are talking about (orientation is good)?
Next?
PS: since I'm not at the CAD box, had someone run 4mm HT steel same dimensions, similar straight pull results, 7.824mm plastic deformation. Thats double thickness for 2mm less permanent deformation. Still at 5000kg. Not testing higher to a safety factor and rating down to a SWL. If these were correctly designed and their SWL was 5000kg, I would have no issue because:
The designation of a SWL means they have been tested to a Miniumum Breaking Strength (MBS). SWL=MBS/SF. SWL is commonly 1/5 of MBS. A series of product are tested, a MBL is established, that figure is divided by the Safety Factor (often 5:1). So the minimum point established that it will break at is 5 x the rating. This is the std used by everyone working with lifting equipment which is why we generally do not have a problem working with same equipment for recovery. This IS NOT the std that the Luke points have been assessed to.
Informed guessing would have me make that out of (and this is just for a 5000kg load on the metal) 6mm MINIMUM and increase the width (same webbing size cutout) by 15mm each side (add 30mm to overall width) and 20mm to the strap edge.
AND we haven't considered the variable of the webbing may have the bow end of a shackle on it, which, being curved will load the webbing more on the outside. So more offset loading again.
Next?
Excellent now we're getting somewhere, so to pr?cis:Should maybe contact LUKE themselves rather than this seller, just sayin...
- 6mm plate 30mm wider
- 30mm wider strap or 3" webbing
- Longer loop
Maybe a little beefier like this :
http://www.ecproducts.com/products/1...me-each-64-66/
https://www.aulro.com/afvb/images/im...015/04/400.jpg
Maybe put a hole for a 20mm high tensile bolt if that's what it needs ???
You can get thicker webbing though, same thickness as snatch straps maybe???
You're starting to talk about a pretty strong bit of kit now aren't you clubagreenie??? 6mm plate, thick 3" webbing, 20mm high tensile bolt. That has to be as strong as any connection you'll get into a 3mm chassis, isn't it?
Its a really simple strong idea.
The AULRO recovery point, designed by AULRO for AULROLIANS! Haha
RUD swivel recovery points.
/thread.
Seriously, the fact that this thread is still going is slightly absurd. The question the OP presented has been unanimously and thoroughly answered with a resounding no. Not a piece of equipment designed to be used for 4WD recovery applications.
There's nothing wrong with Philco points. Had them on for upwards of three years, used many times in lots of different applications including angled pulls and no problems.
Don't go recovering people like a dickhead and you'll be okay, use a bit of common sense.
Quote:
Originally Posted by Islandnomad
Designed (poorly) by someone who is too stubborn to concede the idea is NOT sound, Impractical, increases risk, will be expensive as it won't be mass produced in volumes that would make it cheap.
And highly likely that the only person who would throw cash at it is solely you.
Will wear quickly, will derate once wet......
Give it a bloody rest; it's a crap idea for this situation.
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