Front Suspension

Front Suspension

I'm going for semi-triangulated 4-link. It will allow me to re-use the hockey-stick mounts on the chassis, and also seems to be a purer design than a 3-link in my opinion. As I'm going to run a 4-link on the rear, I'm hoping to get a balanced suspension - front <-> rear.

Pirate 4x4 etc goes into the geometry of link design and geometry to the n'th degree, I've read an awful lot about it, heck I even understand some of it, but I've chosen to ignore a lot of it. Strange you may say, but I've not gone for the longest links possible, as I've re-used some of the Land Rover chassis mounts, this has saved a huge amount of fabrication time. Also I plan on running fully retained coil springs, so I am never going to get into extreme suspension travel where the geometry becomes more crucial.

	First fine yourself some raw materials. On the left a Land Rover trailing arm. On the right some 48mm OD seamless tube, with 7mm wall thickness.
	In order to use Land Rover bushes, I've cut the ends off a trailing arm to act as a bush carrier. For the other end I've chopped up some hockey sticks, and ground them so they fit inside the tube.
	Here is the lower link just tacked into position, there is a bend to compensate for the slightly wider Unimog axles.
	I've elected to use the mounting hole closest to the axle, I believe the others may well bend, despite being 6mm steel. I would have preferred a little more vertical separation, but we will see how it behaves.
	Here are the upper links. Again using Land Rover bushes. These are a stock pair of Land Rover trailing arms, but sleeved with tube for extra strength The mounts will be boxed in once I've tested the travel and binding of the suspension
	With the springs out to test the travel. There is about 29" between the upper and lower spring seats
	On full compression, there is about 9" between spring seats, so some 14" front shocks are going to have their work cut out. I'll need some longer bumpstops to limit upwards travel. i.e. the 4-link mounts punching their way through the fuel tank.
	The inner 4-link bushes on full droop. The heavy axle is pulling the bushes into mad distortion. I doubt this will happen in reality once spring and shocks are connected. The mounts will of course be renforced.
	Again the outer mounts on full droop - yes I know I've got some welding to finish and some painting to do.
	Here are the upper links in action
	Plenty of droop. Diff now retained by a centre limiting strap.
	Here one full compression. Bumpstops extended so that the 4-link mounts don't hit the tank guard (too hard!!) Must remember to do up those bolts.