Crappy bolts...Part II (With Photos!)

**rick130** · 22nd May 2007, 05:33 PM

Originally Posted by isuzurover

A bolt in tensile strain is only as strong as the minor diameter - a bolted joint correctly designed in double shear, should be as strong as the major diameter, as the shear forces should be acting on the shank and not the thread (i agree - not always possible with standard sizes).

<snip>

that's what I was trying to say Ben, just wasn't very clear about it, hence my comment re AN bolts where they are selected for grip length to use in double shear.

**rangieman** · 22nd May 2007, 05:42 PM

well my 2 bobs i would say it is more a tie down point for transporting and not a recovery point and thats coming from one that use to do car carrying

**ladas** · 22nd May 2007, 05:47 PM

Originally Posted by rangieman

well my 2 bobs i would say it is more a tie down point for transporting and not a recovery point and thats coming from one that use to do car carrying

Well I just hope you get some change from your 2 bob

**rangieman** · 22nd May 2007, 05:51 PM

Originally Posted by ladas

Well I just hope you get some change from your 2 bob

Well every one else has a opinion and thats what this site is for information and advice and opinion,s

mcrover · 22nd May 2007, 06:11 PM

Originally Posted by dullbird

mate i dont know the awnser i'm quoting you what the guy who writes alls the modification rules said when somone asing him about making there own custom bullbar

No worries mate, I was involved like I said 10 years ago in the design and building of ROPS bars and fitting towbars, bullbars and nudge bars.

I was only involved in basic design and building the jigs as I wasnt qualified to weld that stuff but I remember how hard it was to get it complied.

Getting back to the subject, I would say that that bracket is a tie down point, granted its pretty bulky but from the shape of it I would have been dubius about snaching off that because of the shear forces against the bolts as well as the fact the bracket would have been under fairly high twisting forces, any movement or damage to the bolts and they would have been under way too much load no matter what the bolts were, even HT.

More than likly (but not for sure) that bar would have been mounted with LT bolts anyway as to not have too much affect on the crumple zones or air bag deployment in an accident.

I just fitted a nudge bar to my inlaws Jeep to mount some lights on and it came with Non rated bolts so I rang TJM and they said that you cant use HT bolts in it as it will affect the Airbag deployment in an accident.

Even if you had fitted a proper recovery point bolted onto the same spot, it may have either made the bar non compliant (If you have airbags) by fitting HT bolts or still been a weak point.

It would have looked like a fairly substantial point to use as a recovery point Im sure, and Im sad to say that all 3 people whom checked it all gave you the wrong advice.

Well on the up side, I think all of us are going to go and check our bolts before we go away next.

**Ace** · 22nd May 2007, 06:17 PM

Originally Posted by incisor

it is not recommended that you use any towbar or bullbar as a recovery point

so what about TJM and ARB winch bars that have the recovery eyes in direct line with each chassis rail? These are put there by the manufacturer, and everyone recommends the use of tow bars as recovery points just not the towball.

There just seems to be alot of contradicting info floating around. Matt

**sam_d** · 22nd May 2007, 06:29 PM

In my limited opinion I would say it was not a tie down point.

My reason for this is: why would anyone fit a tie down point like that? What reason would Land Rover (or anyone else) have to make and install a special one off tie down point when the normal tie down points are adequate?

I'll get a couple more pics at the weekend showing the recovery point a bit better to get more advice/opinion

**dobbo** · 22nd May 2007, 06:36 PM

Originally Posted by Ace

so what about TJM and ARB winch bars that have the recovery eyes in direct line with each chassis rail? These are put there by the manufacturer, and everyone recommends the use of tow bars as recovery points just not the towball.

There just seems to be alot of contradicting info floating around. Matt

Are you talking of bolt on eyebolts on the front of the bar, or the triangular pieces welded onto the bottom of the bar which both TJM and ARB recommend notr using as a recovery point?

Anyway

The towball spreads the load evenly through both chassis rails. Thus halving the stresses on the chassis rails Like an equalizer strap.

The eyelets on a bullbar effectivally should do the same thing if used both at the same time (with an equaliser strap)

As I've said before would you really trust your life on a piece of metal welded or bolted to the bullbar?

**rangieman** · 22nd May 2007, 06:46 PM

Originally Posted by sam_d

In my limited opinion I would say it was not a tie down point.

My reason for this is: why would anyone fit a tie down point like that? What reason would Land Rover (or anyone else) have to make and install a special one off tie down point when the normal tie down points are adequate?

I'll get a couple more pics at the weekend showing the recovery point a bit better to get more advice/opinion

well its not a recovery point you proved that

mcrover · 22nd May 2007, 06:49 PM

Originally Posted by sam_d

In my limited opinion I would say it was not a tie down point.

My reason for this is: why would anyone fit a tie down point like that? What reason would Land Rover (or anyone else) have to make and install a special one off tie down point when the normal tie down points are adequate?
I'll get a couple more pics at the weekend showing the recovery point a bit better to get more advice/opinion

My answer to this would be because the fitment of the bar may have made the original points difficult to get to or damaging to tiedown equipment or it was just a poorly designed recovery point as because of leverage it multiplies the pressure on the bolts.

By the way what size are the bolts? 3/8"? 1/2"? were they corse thread or fine? Were they checked for tightness at any stage? Was there rust showing through under the bolts? Did it have washers fitted? Did it have Nylocs fitted? these are all questions that need to be answered before it can be deffinatly blamed on the bolts.

Also was the snatch a soft or fairly fast snatch with maybe too much slack and speed putting a crapload of force on the point and I take it it was from 1 side only which is fine if your not going to be too bigger load on the point but if your really bogged it takes a hell of a lot of force to remove the vehical so you would connect a sling to both points and connect the snatchy to that so that it has even load across the chassis and 1/2 the load on each point.

In these bad situations I winch as it is easier on everything, I only snatch someone out if it is hung up on something or is just slipping and sliding around and cant quite get there or else it can just do too much damage, Just ask my mate Stu with the big dent in the back of his Pootrol from a broken strap where I winched the bloke out slowly letting air get under the car to relieve the vacuum and not try to pull what is basically like a stump in the ground.

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