Why body lifts suck

[turoa]

I stole this from another site and its a good example of why they suck and what can happen (the bodylift acts like a lever on the mount).







discuss

[mudzilla]

Good point Tu's ,, but a bit more going than just a body lift eh .. Like rolling it big time ..

[turoa]

Good point Tu's ,, but a bit more going than just a body lift eh .. Like rolling it big time ..

yea but generally when you roll the cab doesnt fall off

[DaveM]

Just out of interest, how did the body lift cause the cab to seperate from the chassis?

[sig]

Just out of interest, how did the body lift cause the cab to seperate from the chassis?

puts more stress on the mounts by having more leverage on them

[Safari Swb]

looks like the cab was going to be pretty fucked anyway regardless of bodylift

[LOLYF]

It just makes it easier to replace the f###ed body when it's half off

[Chopper01]

Yea TU's Im with you , I cant stand havein body lifts in my trucks, as it changes the center of gravity that makes the truck more top heavy and prone to roll over, people say its a cheap way of fitting bigger wheels (and they are right) but I have never done this to run big wheels , all I have done to my lux is put a set of rears in the front and some good but not lifted springs in the back and it cost me $20 also cut the guards up and I am running 38.5 boggers , well thats my 2c on the topic

[flyingbrick]

More complex than it looks.

The LEFT hand side of the body/roof is pushed in.

So why is the body leaning to the left and not to the right?

[Chopper01]

It was said that he rolled on a gravel road so could have been going like a cut cat and farked up and rolled , also its a 3inch body lift

[Bulletproof]

I think people are drawing conclusions before getting all the facts about what happened.

No truck will stand a 100metre + drop. In trials with full cages they are restricted to banks and not hills for this very reason.

My front axle has been moved forward 30mm and I have a 30mm lift and are completely happy with it form a safety point of view. My 35s still just rub.

Cheers Richard

[Jafa]

Yea TU's Im with you , I cant stand havein body lifts in my trucks, as it changes the center of gravity that makes the truck more top heavy and prone to roll over, people say its a cheap way of fitting bigger wheels (and they are right) but I have never done this to run big wheels , all I have done to my lux is put a set of rears in the front and some good but not lifted springs in the back and it cost me $20 also cut the guards up and I am running 38.5 boggers , well thats my 2c on the topic

Boggers they'll be shit on the rocks Chop, or have ya given up on rockcrawling? Post some pics of this beast!

[darinz]

Yea TU's Im with you , I cant stand havein body lifts in my trucks, as it changes the center of gravity that makes the truck more top heavy and prone to roll over, people say its a cheap way of fitting bigger wheels (and they are right) but I have never done this to run big wheels , all I have done to my lux is put a set of rears in the front and some good but not lifted springs in the back and it cost me $20 also cut the guards up and I am running 38.5 boggers , well thats my 2c on the topic

Actually a bodylift will keep the COG lower than with a comparable suspension lift as it keeps the chassis lower but allows clearance for bigger tyres.
But I still agree BL's should be small and the best way to do them is not easy. My BL has been done by cutting the mounts off the chassis and welding them back on in the desired position. Was easy for me as I shifted the cab at the same time. Obviously this is not cheap, and requires a cert but then ALL bodylifts require a cert anyway.

[GQ grannie]

Funny how a body lift caused the cab to shift, but if you look at the pic properly it all so looks like a tray lift ,trays still there tho a little like a banana. if done correctly a body lift is quiet safe or other wise do you think they would pass them as a modification on a mod plate ,looks to me like he tried to save a few dollars when it came time to buy the bolts for the lift wrong grade and no strong enough!!! the lift block looks fine and still sitting where it should be bolts completely missing ? either pulled through the floor or snapped,doubt he had it engineered


cheers Lindon

[Moriarty]

Hmmmm Lookin at the photos..

Compare that cab/tray to a full body vehicle like, for example, mine.
I have 5 body anchor points down each side.
could somebody tell me how many anchor points THAT truck would likely have?

Would the (probably) lesser number of points contribute to it being wiped off when it quite obviously rolled?

Would my body be held down firmer than HIS with ten anchor points? Suppose I was silly enuff to roll it..... I am silly enuff for lots of things.......

and WHY would a 50mm body lift reduce the strength of the anchor points, assuming the NEW bolts were of equal rating.

Remember, I AM a newbie at 4wd, but have considerable engineering knowledge and experience.

[IcedJohnno]

Having a body lift allows a torque reaction (force x distance) to take place rather than just a shearing action (force).
Without looking at that vehicle in particular, I believe that the torque reaction in this case has overcome the reaction force that the floor can generate. This happens when the lift height of the blocks is greater than the block diameter and the clamping area of the block buckles the floor. The buckling then distorts the floor considerably weakening it and then the floor will tear out.

So the failure mode is;
force x distance + buckling leading to failure
versus
just the shear force.

My experience as a passenger in '99 with a standard height double cab Hilux proves the point.
All body mounts were absolutely fine yet both the nose and the tailgate had taken 20 metre vertical fall impacts repeatedly. (9 barrel roles down 60 deg slope and then 7 end-for-ends over vertical bluffs. About a 400 vertical metre fall all up.)

Once the fourth recovery attempt by larger and larger recovery tow trucks was successful, I twice went to the insurance yard to inspect the wreck from a design engineers perspective, and to count my many blessings.

On the passenger side the roof was below the mid-level of the glove box and the C pillar was twisted and sheared like you can with an ali coke can. This is normally about a 75 x 100 mm box section so that gives an idea of the forces involved. The RHS of the roof was not a lot better. Two seatbelts had failed through the buckle mechanism. The fact that the front bench seat back failed and folded over the top of the remaining rear passenger saved my life. I was front centre to start with and the top of my head initially was supporting the roof centre like a roll hoop!

I do not think you would often get a more severe crash accident than that, yet all six occupants survived, although one sadly is a tetraplegic.
Had we had a body lift with badly designed body lift mounting areas, I doubt those two of us left in the vehicle would be alive now. possibly some of the others would not be here too.

My suggestion as a Mechanical Engineer is to ensure all bolts are rated 8.8 (High Tensile), they are as a minimum the same diameter as original, and that the floor area has reinforcing both sides where the bolts attach to the body.
By reinforcing I mean a minimum of 2mm steel plate 50mm larger in diameter than the lift block. This needs to be on both sides of the floor i.e. sandwiching it. I would also put a large heavy flat washer above the upper reinforcing plate and under the bolt-head / nut.

Some chassis mounts may need stiffening as well. This will require some welding by somebody who is competent. Heavy flat washers should be used between the chassis mount and the nut / bolt-head.

By doing the above you are spreading the load and thus putting those areas of the floor through much less stress (stress = force / area) Less tress will mean that the floor is much less likely to fail.

cheers John

[coxsy]

someone was watching over you john

[IcedJohnno]

someone was watching over you john

The words Divine Providence have always been near me.
I am grateful for this.
Through this and several other extremely close near-death experiences, I have come to realise that I am here for a purpose.

[Moriarty]

someone was watching over you john

The words Divine Providence have always been near me.
I am grateful for this.
Through this and several other extremely close near-death experiences, I have come to realise that I am here for a purpose.

Nah, mate, it was a midnight accident when they was both pissed....... Near death experiences...... man, dont THEY give you a healthy attitude to life and living???

However. Thank you for the learned discourse. I learned a bit. THAT'S allus a good thing.
BUT, the fact that it was a cab,tray setup wasnt addressed. I am still sure that a full body with more mounting points is a stronger setup. Would that Lujx/scurf have survived better if it had been a full body with ten or more mount points?

[rangimotors]

a surf has 10 and a hilux d/cab has 12..

[Moriarty]

a surf has 10 and a hilux d/cab has 12..

Thanks, Rangi, THATS the info I wanted.

therefore that d/cab hit the dirt damned hard. Notwithstanding John's comments.
the increased torque and bending moment on a long bolt because of the lift spacer is not THAT much, considering the rubber blocks on both sides of the chassis mounts, and the fact that those same mount points are arranged in a large rectangle.

It sez a lot for the upper body integrity too, its hardly damaged in the passengers head area, considering the fact that its ripped off of its body mounts.

B

[NJV6]

12 - Are you sure!

The deck ones don't count. And I think you'll find its alot less than 12!

[rangimotors]

my bad, 6 in the body and 6 in the deck. Just flicked back to the pic again and its a single cab, im sure someone will let us no if they are the same.

[Moriarty]

my bad, 6 in the body and 6 in the deck. Just flicked back to the pic again and its a single cab, im sure someone will let us no if they are the same.

That makes 3 down each side.

Hmmm not gonna take a helluva ding to move THAT body yes, no?