Dual cab chassis thickness?

All dual cab owners who plan on loading them up and heading off road should really get the chassis strengthened....small price to pay for peace of mind.

The D-Max's have been cracking axle housings, axles instread of bending chassis it's a much better alternative.

oops, thought it was a Nissan, here is the Hilux, $130.00, still very cheap insurance.

Probably help a lot, but why should that have to be done?

Do it right the first time !


Cheers Axle.

Probably used as part of a GVM upgrade.

My GVM upgrade did not have anything done to the chassis, it was purely suspension parts that were changed.

The biggest problem from what I can see, is having to much weight out the back past the rear axle, keep withing the manufacturers specifications and you should be fine as long as you are taking the off road track at a slower pace.

Axle, precisely, was just giving a different view on it.

Kazza, my GVM upgrade didn't have the chassis plated, getting that done next month when my Nissan is Dual Cab cut, but the rear axle was braced. Keeping with in the manufacturers specifications is difficult due to the "false" claims re carrying capacity, more owners need to THINK about where and what they carry on dual cabs and consider preventative additions, not just heavier suspension.

Even if you THINK you are not overloading the chassis, as above, cheap insurance .

I know what you mean RMD, I own a 013 ,2wd Mitsubishi triton and although I like the vehicle and have had a excellent run with it i've yet to fit a tow bar to it for the reasons you have mentioned , My towing is accomplished with a 130 landrover defender,strong enough but age is catching up.


Cheers Axle.

RMD just wondering about your comment " it is the top and bottom of the chassis that gives it strength and not much provided by sides " ??
Wasn't sure what you meant by that ?

Nick, in engineering design, the upright member of any structural section has a lesser strength factor than the top and bottom horizontal members.

If you want to strengthen a weak box-section, you can gain more strength by plating the top and bottom members, rather than plating the side members - even though the top and bottom members are narrower.

You will often see structural sections with holes in the upright member for weight reduction, or for other purposes.

These holes only reduce the structural strength of the section by a small amount - as compared to cutting holes in the top or bottom member, which will weaken the structural member by a serious amount.

Example

Just adding, that heavily-loaded steel sections must only ever have evenly-shaped, or perfectly-cut circles of steel, removed from the vertical member - as jagged-shape cutouts will only lead to cracking, commencing from the sharp angle formed in the jagged shape.

You will notice in the example above, where a very large rectangular section hole has been cut out of the vertical member of the structural section - but this substantial steel removal has been compensated for, by the addition of horizontal plate sections above and below the hole.

Cheers, Ron.

Cheers Ron : but if the upright section is allowed to buckle like you'll see in these vehicle chassis most likely it's not going to help ??

Nick, if the load on the chassis section goes way over any designed strength level, it will buckle in every member, regardless.

Most engineering works on a minimum of 100% safety factors, meaning the component can handle double the designed weight before it fails.

The problem is, if you are loaded to the max, and you hit a gutter, a pothole, or a sunken culvert, that makes the vehicle bounce onto the bump stops, the loading on the chassis can be more than double the weight it's carrying.

It's even worse if the vehicle jumps up, prior to hitting a gutter, and then comes back down hard. Something like that would triple the loading on the chassis rails.

Cheers, Ron.

If you want to see serious structural strength, then look at the I-beam. A top and bottom plate, separated by a single member the same thickness as the top and bottom plates. Its really only there to keep the top and bottom apart.

When loaded, one side is in compression, the other in tension and the middle is still really just keeping the two apart.
Aircraft wings are similar, skin on the top and the bottom and a whole lot of lightly constructed bugger-all keeping the two apart.
Composite panels are a stiff skin top and bottom and honeycomb, foam or balsa in the middle.

Most of the utes you see cracked, the crack will have initiated from a defect in the top chassis plate where it has been getting cyclic tension (stretched) for a while, either a nick in the metal or where some engineer thought it would be a good idea to weld on a tray/suspension/body attachment point and the weld heat changed the metal properties. On heavy vehicles, welding the chassis is a big no-no, everything is bolted or riveted onto the sides of the chassis.

Fish plates on the sides of the chassis aren't the best way to add strength. A strap laid along the top plate and then welded along the edges of the chassis rail would do a lot more, but as you have to pull of all the tray and body attachment points, brake lines, looms etc. to get a clear run, then plating the sides is certainly easier.

Hoyks - A well written piece of advice - but I beg to differ on just one point.

It's relatively uncommon for an I-beam to have the vertical section ("the web"), the same thickness as the top and bottom sections ("the flanges").

In practically all I-beams (more correctly known here, as Universal Column or Universal Beam), the web is thinner than the flanges.

There are a few UC's and UB's with the same thickness in the web, as in the flanges, but they only make up about 5% to 7% of the UC and UB beams currently being produced.

You can find the reference guide on UC & UB thicknesses in the link below.

Surdex Steel Products

Cheers, Ron.

Just a slight correction to the above post, a UB or I beam is commonly used in the horizontal position wereas a UC or H beam is used in a vertical position.

Ivan that's good if the DMax chassis is better than some, My point was looking at the inside of the end of the rails of the utes mentioned( neither had towbars,fitted)
you could see a marked difference in chassis thickness .If the Lux had the same width and thickness in steel as the landcruiser then it would visually look a lot stronger., But maybe looks don't count!.


Cheers Axle.

,

Ivan, it's got nothing to do with the engineering. It's just that time of the month to post a contentious subject to get people to react.

Monthly Troll subjects


Every post uses the same formula.

1)Post up a seemingly innocent recent observation or long term memory on something contentious, or people will react to.
2)Make a personal observation/opinion to kick off the day's play
3)Post a hypothetical question to stir up the forumites.
4)Sit back and watch the reaction for those who bite.

8 times out of 10 the OP never even revisits the thread if it has enough momentum. Occasionally he comes back to give it a kick.

Also, almost Zero replies on any other subject other than his own threads. And 1 new troll thread a month.

The OP has no interest in topics started by others, and even no interest in answers to his own hypothetical questions unless the thread needs more fodder. The subject is irrelevant. Go look at the historical subjects with not 1 follow up comment or question from the OP much of the time.

Classic troll behaviour. Don't feed the trolls. The next phase is he will go on the attack of anyone who questions the motives. Getting personal and rude, random attacks. It's a well-worn track for this OP.

I don't know why EO has let this go on for so long.

How are you BooBook? ..Still as critical as ever!

Haven't seen many complaints about my posting

Actually its you that wants to carry on stupid!

Also I haven't seen any interesting posts from you over time

just your normal criticism when someone mentions the word Toyota.

Do you want me to expose some of your critical replys?

Sorry I won't, that wrecks a good forum ,didn't take much notice of what Michelle had to say a while back did you?

Anyway lets all have a nice Day

Cheers Axle.

You're consistent. I'll give you that.

Off TOPIC comments...senseless comments that have very little to do with the subject that are not helpful ! do nothing but create Bad Blood and are a bad look For everyone .

Keith B2
Not sure what Collyn is talking about a possible reduction from 3.5mm to 3mm. I have a 2011 Dmax and apart from the areas which have a doubling inside, the chassis thickness is slightly under 3mm as it is.

Keith - What Collyn Rivers has failed to comprehend, is that vehicle manufacturers are constantly trying to reduce vehicle weight, to improve performance and fuel economy.

As part of the race to keep vehicle weight light, manufacturers use thinner section, higher tensile steel, in chassis and body components.
They also utilise an increased amount of aluminium to reduce weight.

A thinner section piece of steel with a higher tensile strength is a stronger section.
Most vehicles today have vastly thinner section body panels than vehicles of the 1960's, 1970's and 1980's.

Todays body panels don't dent as easily as earlier body panels, but they are vastly more difficult to repair. As a result, panels are more often than not, replaced, rather than repaired.

Structural members of the chassis and body made from HT steel are stronger, but are also difficult to straighten, leading to more write-offs than previous models.

The downside of higher tensile steels is their tendency to corrode faster.
However, improved coatings have led to improved life for high tensile steel vehicle panels, despite their increased tendency to corrode.

Cheers, Ron.

Strange that I've always thought when you lean on a new car and the panel flexes and is very easy to dent just with the push of a hnd it would be weaker, not stronger.

I think they are in a minor dilmma and are reducing metal thickness and strength in some areas to compensate for all the extra crap they fit people think they can't do without when they're suppose to be driving instead of fiddling with junk.

Batts, todays panels can still buckle fairly easily - but the buckle pops back in many cases. There's plenty of people specialising in popping out dents for todays cars.

Look up "paintless dent removal". The difference with the older vehicles with softer but thicker steel, is the panel would bend in and stretch, and then stay bent.

The only way to get the dents out in the older cars was hammering the metal back into place roughly, try to shrink the stretch using heat and a cold wet rag, and then fill the ripples in with bog.

Cheers, Ron.

I was talking to a vehicle engineer the other day, engineering is basically trial an error. His company is a registered through Australia to do vehicle upgrade certifications. He was telling me about one vehicle manufacture that had reduced the thickness of chassis to lighten the vehicle and improve performance and economy etc not to mention reduce the cost. It worked ok so they decided they would decrease the size even further, they then had cases of chassis failure so decided they had gone to far and increased the size a little.

Nick, the dual-cab chassis-bending problem is simply one of excessive leverage, coupled with maximum loading (and often, overloading), coupled with speed and rough roads.

I'm sure the manufacturers of the dual cabs never imagined the size of the bodies (campers), and the length of the trays, that would be fitted to their vehicles.

Any increase in weight and length, from around 300mm past the end of the chassis rails, simply adds to the leverage the tray or camper applies to the chassis members.

There are many dual-cab trays and campers that should have never been allowed on the road, to my mind, they are simply too long and carry too much weight on the chassis behind the rear axle.

If you want a proper load-carrying arrangement, the axle is best positioned as central as possible under the tray/camper/body.

You never see any dual-cab truck, with the amount of rear overhang, that so many dual-cab utes have - but for some reason, dual-cab utes have been allowed to get away with it.

But I think you're right, to a certain extent, the manufacturers aren't too concerned about bent chassis' - particularly when they can blame it on "operator abuse", and "body designs outside accepted criteria".

Cheers, Ron.

Most people don't ever consider "inertia" which is magnifies by sudden movement and added weight on the overhang Ron mentioned. Try this inertia test. Place your hand on the bench, rest a house brick on your open hand, all ok with the weight? Now lift the brick 200mm and drop it onto the open hand. Inertia will educate those who try it. Same with a
vehicle chassis.

I now have five broken fingers!!….LOL.


Cheers Axle.

You can demonstrate that more effectively by resting a brick on your toes, then dropping the brick on your toes from shoulder height. A lesson you don't forget. :-)

That's the 4WD triton RMD..Been well aware of the problems there.

Mine is the single cab 2WD , with a decent set of CSR mag wheels fitted and Bridgestone 697 AT Tyres. Transforms the thing into a different ute, as far as handling goes.

You can load towards the front a lot more than the dual cab, But i'm still not impressed with chassis structure , it s more of a run around these days so heavy loads aren't a issue luckily. Very good engines strong gearbox and diffs.

So don't write off Mitsubishi altogether, also have you noticed the sales figs

.all about price I know ,but theres a few getting around

Cheers Axle.

Axle
Yes, single cab chassis is a different story. They do sell well, ie, priced, and if not too stressed do good job.

When we were at kalumburu / mcgowans last season there was a Nissan Patrol ute single cab towing boat and had some sort of roof rack as well that came in with a bent chassis not something you see often I would think .Talking to the welder mechanic at mcgowans last season he was telling me that he did a fair amount of welding repairs on vehicles etc.. also my mates previous Nissan Patrol ute with coil springs bent and broke the chassis at the rear coil hanger he has a camper that fits on the back which probably has something to do with that . It's not just these lightweight ute chassis that bend .

Didn't happen to be a GU Patrol apparently their chassis are lighter than the GQ and are prone to having issues.

Also the coil rear end I think on all of the ute's, wagons can have issues bending the top rear coil spring bracket so they're flogging cross braces of to help strengthen them. They're are convincing a lot of GQ owners that they require bracing I'm not 100% sure but I don't think they lightened the chassis or bracket mount on that model only started when the GU came about but still lots of GQ owners are getting them fitted in the panic.

The amount of money some people spend setting their vehicle up only to have it fail when sometimes loading correctly or reducing what they carry buying the correct vehicle or paying a bit extra for mods like chassis ext which can solve the issue but at the expense of larger turning circle having to plan where to park when in town limit some of the tracks you can drive on no big issues though consider the heart ache that can happen when things crack or break off road.

My 26yr old GQ has no mods to the coil spring mounts it has a constant load on the rear around 500kg which it supports easy but the axle is closer to the centre of the tray than most other dual cabs where it should be. The bare 1800mm canopy weighs 120kg my 2 spare wheels around 80kg are in front of the axle and not hanging of the back trying to look like a cool outback adventurer stressing the chassis and spring mounts also 2 aux batteries, 60ltr water tank are in front of the springs the fridge pretty much over the axle and light stuff behind.The long rang 145ltr fuel tank is the only heavy item at the rear it's driven like a 4wd not a race car especially in remote areas and hasn't cracked or bent anything yet. Not the most practical vehicle in length but has out lasted a lot of others who carry lots of weight on their back.