BT50 Boss suspension set up for a slide on camper

[Randal Canning]

Hi fellow slide on camper owners
We have a 2010 BT50 bravo dual cab with a large alloy bull bar and alloy tray.
We bought a Active Campers slide on camper 2009 model recently and hit the road up to Airlie Beach QLD pulling into spots along the way. High way travel.
Have fitted new ARB OME performance shocks front and rear.
I fitted air bags 3 years ago and now with the slide on camper running at 30 psi as springs are not strong enough.
-Slide on camper weight 500kg
- under tray slide out draw 70 kgs
- extra load 100 kgs
Found it floaty on the front end and fitted the spare tyre to the bull bar, this help out lots.
Still not good as bottoming out.
Had feed back from 2 off suspension companys, ARB suggesting 400 kg leaf springs pack replacement.
And CCS suspension suggesting 650 kg pack.
Also would like a recommendation on the front torsion bars size recommendation.
Looking at doing places like Frazer island and Gibb river road, if we could get some recommendations from fellow owners of the same set up that would be great.
Just want to get it right first time.
Cheers randal

 

[Randal Canning]

I am not sure about the photo above have placed 2 off photos with vehicle and Suspension hope it shows up .

 

[Batts88]

May be standback and have a good look at it. Does it really look, feel safe on the road ? going by your description you have exceeded the vehicles limits by a lot. 500kg on the tray that's asking for trouble and where is the sprare on the bullbar if so that may be illegal and helping to add more stress to the chassis so be prepared for it to bend or snap one day.

Seriously your set up sounds very dangerous you may need to get a different vehicle like a single or extrcab or get a chassis extension done to get the rear axle near the centre of the tray so you don't need massive springs to try and compensate for a poorly set up vehicle.

Any company that suggest a spring upgrade will help are dangerous fools. Do the right thing and fix the issue correctly befoe you have anaccident and injure or kill yourselves or other innocent road users don't kid yourself that it can't happen. Sorry I don't mean to jump down your throat but don't like dangerous vehicles on the road.

 

[2luxes]

I am not surprised your front end is up in the air and the car feels floaty. The rear end of the chassis is being levered down behind the axle. No amount of stiffer springs, air bags or blocks of wood between the axle and the chassis is going to fix it.

You have been thinking about weight, and your car may be under its maximum legal weight, but have you thought about mass and it's location in the car?

Mass is the amount of material in something. You could place a brick on a beer glass and it won't break but drop it on the glass and it will. The weight of the brick did not increase. The glass broke because the material in the brick fell, built up momentum, and hit it with considerably more force than it was applying when it was stationary.

When your car is in motion, particularly on uneven surfaces, the axle is going to be constantly rising and falling rapidly. Imaging the stress on the end of the chassis when it has to instantly lift that material or catch it when it falls and instantly heave it back up again. To make matters worse, the forces going up into the chassis increase by the square of the speed.

The internet is full of incorrectly loaded cab chassis utes with bent chassis. You will almost certainly join them if you keep driving with you car loaded that way.

Your other problem is handling. You car has been designed to run out wider at the front if you go too fast into a corner or swerve suddenly. With all that weight on the rear axle, you are in with a real good chance of having the rear going first and the car spinning around and facing the opposite direction, that is if it does not roll over.

The front or rear sliding first is known as understeer and oversteer. Tyres distort when any side pressure is applied to them. An angle known as the tyre slip angle forms between where the wheel and the tyre is pointing. The car will understeer if the front angle is higher than the rear. If the rear is higher, the car oversteers. The front to rear tyre slip angle ratio is controlled mainly by suspension design, weight distribution, tyre size/design and tyre pressures.

Another thIng to worry about is the axle housing, wheel studs, wheel bearings and wheels. If any of them break, you will be a long way from being the first to have that happen out in the bush.

Unfortunately dual cabs can create a lot of problems when family's load them. They usually know the car's fully loaded weight but they don't realise that a large percentage of that weight has to go in the seats. They were designed to carry five average weight men (currently 87 kg) not five jockeys or five teenage Asian girls. The result is often a car with the back dragging on the ground and the front up in the air although it is under GVM.

 

[red hilux]

maybe you should just buy or build a trailer. Attach your slide on and turn it into a camper trailer

 

[Batts88]

Also I wouldn't even consider Fraser or Gibb River unless you are cashed up and are prepared for an extended stay.

 

[itlldoo]

put it on the back of a F150-truck mate and she would be golden, better re-sale when your done too, not a pancaked worn out BT with a cracked up camper due to everything twisting.
much much safer and comfortable to boot !
sorry the replies are probably not what you wanted to read, its just a bad set up, please consider something else ! good luck mate.

 

[Randal Canning]

put it on the back of a F150-truck mate and she would be golden, better re-sale when your done too, not a pancaked worn out BT with a cracked up camper due to everything twisting.
much much safer and comfortable to boot !
sorry the replies are probably not what you wanted to read, its just a bad set up, please consider something else ! good luck mate.

May be standback and have a good look at it. Does it really look, feel safe on the road ? going by your description you have exceeded the vehicles limits by a lot. 500kg on the tray that's asking for trouble and where is the sprare on the bullbar if so that may be illegal and helping to add more stress to the chassis so be prepared for it to bend or snap one day.

Seriously your set up sounds very dangerous you may need to get a different vehicle like a single or extrcab or get a chassis extension done to get the rear axle near the centre of the tray so you don't need massive springs to try and compensate for a poorly set up vehicle.

Any company that suggest a spring upgrade will help are dangerous fools. Do the right thing and fix the issue correctly befoe you have anaccident and injure or kill yourselves or other innocent road users don't kid yourself that it can't happen. Sorry I don't mean to jump down your throat but don't like dangerous vehicles on the road.

I am not surprised your front end is up in the air and the car feels floaty. The rear end of the chassis is being levered down behind the axle. No amount of stiffer springs, air bags or blocks of wood between the axle and the chassis is going to fix it.

You have been thinking about weight, and your car may be under its maximum legal weight, but have you thought about mass and it's location in the car?

Mass is the amount of material in something. You could place a brick on a beer glass and it won't break but drop it on the glass and it will. The weight of the brick did not increase. The glass broke because the material in the brick fell, built up momentum, and hit it with considerably more force than it was applying when it was stationary.

When your car is in motion, particularly on uneven surfaces, the axle is going to be constantly rising and falling rapidly. Imaging the stress on the end of the chassis when it has to instantly lift that material or catch it when it falls and instantly heave it back up again. To make matters worse, the forces going up into the chassis increase by the square of the speed.

The internet is full of incorrectly loaded cab chassis utes with bent chassis. You will almost certainly join them if you keep driving with you car loaded that way.

Your other problem is handling. You car has been designed to run out wider at the front if you go too fast into a corner or swerve suddenly. With all that weight on the rear axle, you are in with a real good chance of having the rear going first and the car spinning around and facing the opposite direction, that is if it does not roll over.

The front or rear sliding first is known as understeer and oversteer. Tyres distort when any side pressure is applied to them. An angle known as the tyre slip angle forms between where the wheel and the tyre is pointing. The car will understeer if the front angle is higher than the rear. If the rear is higher, the car oversteers. The front to rear tyre slip angle ratio is controlled mainly by suspension design, weight distribution, tyre size/design and tyre pressures.

Another thIng to worry about is the axle housing, wheel studs, wheel bearings and wheels. If any of them break, you will be a long way from being the first to have that happen out in the bush.

Unfortunately dual cabs can create a lot of problems when family's load them. They usually know the car's fully loaded weight but they don't realise that a large percentage of that weight has to go in the seats. They were designed to carry five average weight men (currently 87 kg) not five jockeys or five teenage Asian girls. The result is often a car with the back dragging on the ground and the front up in the air although it is under GVM.

 

[Randal Canning]

Hi All
Appreciate all the feedback, not the feedback i have received from suspension suppliers. i had purchased the camper off Goegre who had a dual cab hilux and informed me that he had been across Simpson desert and the Canning stock route.
Allso had a chat to active campers and informed me that they had fitted plenty to dual cabs.
Fortunately i have a hj75 cruiser with a OME suspension on it which will do the job on the off road situation, not as comfortable as the Mazda.

 

[Hoyks]

1st thing I'd do is load it as if you're going on a trip and take it straight to a weigh bridge and weigh it with the passengers in it. You will then know exactly what you are playing with. The camper might weigh 500kg, but then you put your stuff in it, add water, fuel, bull bar and passengers and you will be quickly at/past the 1019kg load limit of the vehicle.
Get the numbers for the load on the individual axles too. Your max axle loading should be in your owners manual.

2nd would be to ditch the air bags. They have their place, but it would appear you're running the stock springs and 30psi in the bags, so essentially driving everywhere on the bump stops which can't be good for handling or the chassis in the long term. Have a good look for cracking while you're under there, not just near the bump stops, but also where the chassis bends down and runs under the back of the cab.


Take the spare off the front, its illegal and you're not dealing with a rigid framed tractor (or a boat), so ballasting the front is not going to help and is probably putting you over your max axle load anyway.

I'm guessing you're overloaded with a fair amount of the weight on or behind the rear axle. Removing the air bags and fitting springs better suited to the load may help with the load distribution into the chassis, but I don't think it will cure the forward/aft balance issue.

 

[discomatt]

Some light reading

What causes a ute chassis to bend?

What causes a ute chassis to bend and how to prevent it from happening.

www.whichcar.com.au

Good advert for Mitsubishi and Apollo.....NOT

Broken back

www.exploroz.com

New springs aint going to fix you engineering problem but a different set up or car will

 

[Batts88]

Hi All
Appreciate all the feedback, not the feedback i have received from suspension suppliers. i had purchased the camper off Goegre who had a dual cab hilux and informed me that he had been across Simpson desert and the Canning stock route.
Allso had a chat to active campers and informed me that they had fitted plenty to dual cabs.
Fortunately i have a hj75 cruiser with a OME suspension on it which will do the job on the off road situation, not as comfortable as the Mazda.

They may have fitted a lot but I bet they didn't handle very well just have a look at how top heavy and unstable they are on their site. Some people will tell you anything to get your money it's not their problem when you drive off. I like the layout of the active campers but they're not suited for all utes especially dual cabs.

The hj45 would be more suited with the correct springs, shocks set up to handle the weight you want to carry and can also be reasonably comfy when empty.

 

[2luxes]

Appreciate all the feedback, not the feedback i have received from suspension suppliers.

Rear suspensions of any kind do not lift the front of the car. Too much weight behind the axle rear axle does that. The only spring that can bring your front end down is a weight distributing hitch but you must be towing something to use one.

When you lift the two spring steel bars up and hook them onto the draw bar of a trailer/caravan, they lift the car up off the rear axle thereby reducing the weight on it. That is weight then goes to the ground via the front wheels of the car and the wheels of the trailer.

The next time you speak to a suspension company, ask them how their springs are going restore the lost weight on your front wheels.

 

[cam04]

1st thing I'd do is load it as if you're going on a trip and take it straight to a weigh bridge and weigh it with the passengers in it. You will then know exactly what you are playing with. The camper might weigh 500kg, but then you put your stuff in it, add water, fuel, bull bar and passengers and you will be quickly at/past the 1019kg load limit of the vehicle.
Get the numbers for the load on the individual axles too. Your max axle loading should be in your owners manual.

2nd would be to ditch the air bags. They have their place, but it would appear you're running the stock springs and 30psi in the bags, so essentially driving everywhere on the bump stops which can't be good for handling or the chassis in the long term. Have a good look for cracking while you're under there, not just near the bump stops, but also where the chassis bends down and runs under the back of the cab.


Take the spare off the front, its illegal and you're not dealing with a rigid framed tractor (or a boat), so ballasting the front is not going to help and is probably putting you over your max axle load anyway.

I'm guessing you're overloaded with a fair amount of the weight on or behind the rear axle. Removing the air bags and fitting springs better suited to the load may help with the load distribution into the chassis, but I don't think it will cure the forward/aft balance issue.

you’ll find that airbags replace the bump stops so it won’t be riding on them.
Yes, stronger springs will improve that Ute - notwithstanding all the warnings above.

 

[2luxes]

Yes, stronger springs will improve that Ute - notwithstanding all the warnings above.

Can you explain how?

 

[cam04]

Can you explain how?

Because as you’d know, body motion is resolved diagonally through the chassis. The arse end of that Ute will be wallowing around on the airbags giving rise to the front end floating sensation as much as extreme rear loading will - not to mention horrible body roll. Having the rear springs set up by a specialist to carry a known weight is a no brainer. Then they can either adjust the existing torsion bars to match or replace them if needed.
I’d suggest they also stick fridges, batteries and other heavy items fore of the rear axle, preferably in the back seat and under the bonnet.
Like I said in the first post, the warnings above should also be heeded, namely making sure it isn’t overloaded before they start the process.

 

[2luxes]

Because as you’d know, body motion is resolved diagonally through the chassis. The arse end of that Ute will be wallowing around on the airbags giving rise to the front end floating sensation as much as extreme rear loading will - not to mention horrible body roll. Having the rear springs set up by a specialist to carry a known weight is a no brainer. Then they can either adjust the existing torsion bars to match or replace them if needed.
I’d suggest they also stick fridges, batteries and other heavy items fore of the rear axle, preferably in the back seat and under the bonnet.
Like I said in the first post, the warnings above should also be heeded, namely making sure it isn’t overloaded before they start the process.

There is a much better way that is much safer for the occupants and anyone close by on the road and that is unscrew the number plates and screw a car that can do the job in standard form in between them.

 

[cam04]

That’s your opinion. 670 kg is legal and not a big ask and doesn’t have to be dangerous. My Subaru Forester has almost that much payload ffs. Springs will improve his situation no end.

 

[discomatt]

Suspension will make a massive difference, it always comes down to how suspension carries load and that effect is even more important when it comes to towing but no amount of suspension modifications will fix the chassis issues so if he wants that car to do that job properly he needs to address a whole host of problems not just suspension but that would be a massive step in the right direction.
Its because of all the issues and modifications required that make some cars not suitable for a job, it can be done and achieved but most of the time it is a lot simpler and more reliable to just buy a vehicle that is fit for purpose from the manufacturer

 

[Lost1?]

I agree with most of what CAM04 and Discomatt said. How you load your vehicle will make a big difference. However most people carrying these types of campers carry way to much stuff, then fit airbags to compensate. Hence they are regular contributors to "Another bent chassis" thread.

Looking at your pics, if you want to keep the ute and run that configuration I would recommend a 300mm chassis stretch and then upgrade springs and shocks. Having said that expect to pay about $7,500 to extend the chassis and another $2k ish for someone like ultimate suspension to fit upgraded suspension with a lift. The chassis extension will move your rear axle centreline closer to the centre of the load it is carrying, whilst the upgraded suspension will do a better job of carrying the load than what you have now. Both mods will provide greater stability at highway speeds, reduce the stress on the back half of the vehicle chassis and ensure you have a set up that will survive off road if driven sensibly. Oh and remove the airbags too. That front bar looks pretty serious and must be adding a big chunk of weight on the front axle. If you could trim down the cow catcher or fit something lighter that would help.

Good luck with whatever you do next. Show us what you did. We will all be interested.