Outer Limits 4x4 Board

to all the people with big lifts towing their rig on a trailer, what are you doing to prevent premature sag from pulling the car down on the suspension, to stop it from swaying excessively?

I am planning a fully enclosed trailer for my 9" lifted F150, and will have to pull the truck down on the suspension to stop it from swaying all over the place, and unsettling the trailer. but to pull it down far enough to make it fairly solid, will not be good for the springs. what can you do to overcome this problem?

Any tips to build a very lightweight trailer that is fully enclosed. it needs to be at least 2.2m high inside, 2m between the arches, but 2.5 wide overall, and 5.3m long, plus "A" frame.
The floor will be alloy sheet, the sides caravan cladding. the framework for the sides and roof will be light duty mild steel.
Any construction or design tips to make it light?
I was thinking of running the 2 main rails under where the tyres will be, to give strength where it is needed. or will they need to be at the sides?

Thanks

with the suspension just make up some steel sit in bars so you can tie the suspension down till they are wedged against the diff/body/shock mount ect ect


bit like your supposed to do on the front of a motorbike so you dont stuff the front shockers when you tie them down to a trailer

I dunno bout trailer design, but how hard is it to change the coils for some crappy ones for travel duties and save the good ones from being squashed.

I watched a buggy get loaded aT OzRock. It had to be driven over the flares for the trailer tyres. Thus having wheels each side when all the way forward.
If this was high enough and strong enough, you could pull the rig down onto it, rather than squashing springs too much...or some similar idea to pull down onto chassis rather than springs.
Or shove something in before you ratchet down...
christover

pcman wrote:with the suspension just make up some steel sit in bars so you can tie the suspension down till they are wedged against the diff/body/shock mount ect ect

Just like motorbikes

BTW - I just tie my buggy down to the diffs and I dont notice excessive body roll (and it is fairly softly sprung). Mind you I drive fairly sedately with the trailer on.

Turn it upside down Strap it down on its roof LOL

Yeah, a support under the chassis would work a treat.. fab something up that you put into place when its on the trailer, and you can tie the chassis to the support that goes to the floor of the trailer.

Yep, have a look at some motorcycle retailers for ideas on suspension blocks for trailering.

I was thinking of running the 2 main rails under where the tyres will be, to give strength where it is needed. or will they need to be at the sides?

You'll need em on the sides, beefy enough for the trailer spring saddles etc. to weld onto. Weld sections of 6-8mm plate on the RHS for xtra strength and then weld the trailer spring saddles etc to them. Seen too many saddles push thru RHS.
Run the same size RHS X ways where the front and rear tyres will sit and that will spread the load to the outer frame and springs and help stiffen up the trailer.
I agree, make it light as possible but dont compromise on strength where it's really needed, even if it weighs more than you want.

WTF are you gonna tow it all with?
AHha, lock the convertor

CRUSHU wrote: it needs to be at least 2.2m high inside, 2m between the arches, but 2.5 wide overall, and 5.3m long, plus "A" frame.

I think christover is onto something here. If you want 2m between arches you'll need more than 2m between the insides of the tyres. I can't see how you'll get decent sized tyres far enough apart, and inside your 2.5m width.

Design to drive up and over the arches, then winch on to them?

Scott

Your wheels will be on the trailer chasis too I guess.

"...To all the people with big lifts towing their rig on a trailer, what are you doing to prevent premature sag from pulling the car down on the suspension, to stop it from swaying excessively?..."


Could a solution be to use some hydraulic car jacks and actually lift the chassis 1/2" or so onto some (removable) steel support posts so the tiedown load is taken from the chassis through the posts to the platform of the trailer, rather than through the suspension/tyres?

we anchor to the diffs. have done so for 3 years no dramas.

Considered a "Taughtliner" approach, rather than a totally enclosed? Could be a bit lighter and easier to work around when loading the vehicle. You could still mount a 1 metre wide x 3 metre long x 400mm high steel covered toolbox between the wheels of the truck for security.

N*A*M wrote:we anchor to the diffs. have done so for 3 years no dramas.

I've seen his F150, it's F'n huge, easily 1 1/2 to 2 times the weight of your rig and quite a bit taller (higher C of G). IIRC that is a lifted GQ on 35's sitting next to it in his sig line photo...and they were his "baby tyres" on the F150. I dont think I would like that sprung weight that high on a trailer to be "doin its own thang" on bumpy roads.

I can undestand why he wants to tie it down securely.......

if its a hard sided trailer, how are you going to open your doors when you drive it on?

The bloke up the road has a soft sided chev C30 car transporter for sale, it has a sloping tray and looks neat. He uses it for a 56 chev, so it would need to be made a bit higher. let me know if you want his number.

Andy

and whats this trailer going to be towed by?

when i have been towing my 6" lifted SWB patrol around, i normally tie off the diffs, then with another set of straps ratched kdown to compress the suspension and i always adjuast my shocks onto the highest setting,

i understand the drama of not wahting you suspension to sag, but i have had no dramas to this date, afterall, coils arnt that dear when you think about it,

Just make some blocks that fit between the diffs and the chassis rail, then ratchet the body down so effectively you are reaching maximim compression just below ride height.
I have had similar concerns when towing my brothers comp zook around, the coils are light duty and I have had concerns about the damage from extensive compression.
To this date we strap the diffs and ratchet the body down marginally to reduce body roll.

Why not make up some like, extendable axle stands, and wedge them betweed the diff / body.

Would probably be one of the easier ways of going about it.

Where I used to work we tilt tested trucks and buses to establish CoG. When doing this we had to block the chassis to prevent the suspension travel affecting the calcs. Using a huge tilt table and a 100 tonne crane we were getting Ladder Gantry fire trucks and Petrol Tankers to about 25 degrees, doesn't sound much but the high side tyres come off the table.

Make up some blocks for between the diffs and chassis and tie down the diffs.

I used to make up dummy shocks for my race cars. As the shocks used spherical bearings it was easy to use some 1/2" ID tube at both ends and what ever was laying around to join them. Used them for when towing and pushing them around the workshop.

would it be possible to anchor the diffs securely then put some attatchment points on the side of the body up high or on the chassis and put some ratchet straps on these. These second straps dont have to hold the car down, just one at each corner to stop body movement. If you had one at each corner going sideways then they would sort of work together to stop sideways sway.

The would need only take up a bit of tension in the springs just to stay taut.

I was just thinking as well,

we used to tie down army land rover perenties to the back of mogs by the wheels and diffs, then go wheeling with the mog. the landies never moved.

ozy1 wrote:i understand the drama of not wahting you suspension to sag, but i have had no dramas to this date, afterall, coils arnt that dear when you think about it,

9" lift coils for a '79 F150 aren't exactly cheap, or available. They aren't exactly like 6" - 7" coils for a GQ, which I can get anywhere for bugger all.


Shocks aren't too hard to change, but I already have to swap wheels to get this thing on the truck, which is a big enough job already, I don't want to have to do too much more.
Coils are a real pain in the ass to do!

There is 600mm clearance from the chassis to the ground with the car tyres on, so the spacer will have to be quite high.
to drive the car over the arches, will need an extremely high roof, already it needs to be about 7 foot tall inside the trailer

it will be towed by a GQ.

CRUSHU wrote:There is 600mm clearance from the chassis to the ground with the car tyres on, so the spacer will have to be quite high.
to drive the car over the arches, will need an extremely high roof, already it needs to be about 7 foot tall inside the trailer

it will be towed by a GQ.

What is the empty weight of your 150?? Im guessing around the 2700kg mark (with the big tyres on the trailer too), which only leaves you 800 kg for a tandem trailer plus other "throw-ons", before you reach the towing limit of the GQ, the limit of any hitch that you can buy for it, and the legal limit for a conventional trailers.

Have you thought about a 5th wheeler onto the back of a chopped wagon (4 door) or ute? This would give the combination a bit more stability on the road as well as more load carrying capacity.

CRUSHU wrote:There is 600mm clearance from the chassis to the ground with the car tyres on, so the spacer will have to be quite high.
to drive the car over the arches, will need an extremely high roof, already it needs to be about 7 foot tall inside the trailer

it will be towed by a GQ.

To combat against the high roof, maybe you could make the roof so that it folds open with thte pivot point at the font of the trailor?

As DAMKIA pointed out, I'm trying to keep weight to a minimum, to keep within the towing limits. Fancy extras like more framework and hinges etc add to the weight.

Or maybe wheel arches that unclip, slot in a mesh runner for loading, or even just drive over the trailer tyres?
Slot arches back in for transport..
christover

christover1 wrote:Or maybe wheel arches that unclip, slot in a mesh runner for loading, or even just drive over the trailer tyres?
Slot arches back in for transport..
christover

that would make the trailer narrower, and i need it wide, so i can open the doors.
Although that would let me drive it in on the big tyres, which means the roof would have to be at least 9 feet high, and hinged!!