Thread: Independent Suspensions

Has anyone built there own trailing arm independent trailer suspension.

Im just starting a build up on a mates 435 Hornet. Boat/ motor/ stuff weight is about 400kg, final ATM will be 749kg...

Main frame will be 100UC14 gal dipped. I was going tried and tested hilux leaf pack (set by springworks to ATM) and parrallell 1600kg bearings on a 45mm square axle with tojo hubs.

But I have a collection of maybe 5 sets of coil springs, plenty of shock absorbers, assorted bushes and plenty of time - trailer not needed till November.

So part of me wants to make up the frame with attachments for lux leaf packs and also trailing arms - get that gal dipped and sorted. But then play with some trailing arms. Grab a wrecker rear axle or parts from a 75 series - gives nice stub axles/bearings/ simple hubs (drum brakes)
Make up a trailing arm system in 50 SHS 4 or 5 mm and then run LR "metallastic" bushes to the forward cross rail. Retained coil spring from trailing arm up up to a small tower sitting just inside frame rail with centre mounted damper a-la front of LR. Roughly 600mm from axle centre to hull so enough room for damper and spring.

if I cant make it work we can fall back to leaves and still use the spring/damper tower for the damper mount onto solid axle?


Issues:
- I really like simplicity, but hey its gotta be worth a shot!
- How bad will the bump steer be considering that the (axle) will travel in an arc on ~600mm arms with what ~300mm of verticle travel? I figured two bush attachments to rail (same horizontal plane) but maybe need three for lateral stability? I cant be bothered going to a multi link system.
- Central damper is nice for geometry - I have the clearances from back of the envelope calcs but I can see them being a hassle to change with boat on trailer... If we blow a damper I imagine the system would be almost un-towable until changed.
- stop bloody thinking just build it.

Steve

The boat sits on the two long side rails at the back and the two rubber blocks at the front.

The secret is in the suspension - there is very little (if any) road vibration transferred to the boat . On severe corrugations, the boat rides absolutely smoothly, much better than the tow vehicle. The boat is strapped to the trailer at two points and also strapped right around with the canvas cover - virtually making the boat & trailer one piece, so to speak.

Last trip we picked up three boxes of vegetables in Mt Isa to take into Gapuwiyak and stowed them in the boat - not tied down or wrapped. They arrived unbruised 2 days later after 1400 ks of bitumen & over 400ks of very rough road.

When travelling with the motor stowed flat in the centre of the boat, there is between 60 and 100kgs on the drawbar....depending on fuel load in jerry cans in the trailer. On occasions we carry up to 100 litres of petrol for the boat, most of which is stored to the very rear, altering the drawbar loads.

The connection to the vehicle is through a large ex-army pintle hook which we find brilliant, just keep a bit of lubrication on it. Never had any problems reversing even though we have had to jack-knife severely to get out of tight spots from time to time.

I chose this setup for several reasons, one for commonality of spares - wheel bearings, shockies, wheels/tyres etc., secondly, I had everything available I needed, but most importantly, I figured that Landrover got their suspension pretty right on the Discovery and I was putting a little less weight onto the same setup.

Please ask if you want any more details, but unfortunately I can't provide any specifics as the trailer & boat are presently at our daughter & son-in-laws place in Gapuwiyak as we will be back up there in under 2 months.

Cheers Erich