|Posted on 21 October, 2014 at 21:45|
We have looked at the stop and go. Now for a look into the ride and handling department.
“Springs’ are the things! Range Rovers from the start have had a very pliable suspension due to an advanced design, and not many motor vehicles can compare favourably with the Rangie – even now!
Up to the mid-nineties the good old coil spring was all the go but the bright boys got the idea of air bag suspension for the Range Rover. The early attempts were a disaster as regards to ride, handling, steering shake etc. and most of these vehicle have been converted back to coils to get away from the inherent problems – the one plus was that when everything was new and working properly, one could raise and lower the vehicle height at will – very good thing – but this frill soon became a nightmare when the suspension wouldn’t pump up due to any amount of mechanical or electrical problems and you had to thump your way home on the bump stops.
The main problems with the air suspension were compressor failure, valve unit malfunction and the airlines and bags failing. We won’t dwell on this malady and will stick to reference of the original coil suspension.
There are two common spring styles in the Rovers. Progressive and Linear. The Progressive, as the name suggests, gives a softer ride for the first inch or so of travel and then hardens up. Good for the softer ride but not so good for handling and body roll. The Linear coil is wound evenly and gives a firmer initial ride and less body roll. Dependent on the requirements of the vehicle which way you go. – But if you intend to load the vehicle or tow something heavy, then Linear is the way to go.
The length and strength of the coils is “use” dictated. In my particular Rangie, I have a 50mm lift, rear Linear coils with an increase in wire size of 2mm. Because my truck is used basically for towing and is always heavily loaded, I also use poly air bags in the rear springs and raise and lower the air pressure to compensate for times of maximum load etc. For the average Range Rover and normal loading the most common is 30-40mm lift and 1mm increase in spring coil diameter in a Linear spring for both front and rear.
If you are looking for increased wheel travel (i.e. Off road) then you enter a different ball game of longer shocks – modified spring bases – longer brake hoses and sway bars etc.
Getting onto the shock absorbers. Being a heavy vehicle the shocks need to be good and well anchored. There are many and varied and each breed and type have their own area of excellence. You can have adjustable shocks to vary damping for different terrain and loads. Strong shocks to make the truck handle at speed, long travel for off road or the run of the mill “Toorak Tractor” basic unit to give a reasonable ride and handling.
In my case I have gone for a fairly stiff standard length shock in the front and twin high capacity standard strength lengthened in the rear to help with the rigor of heaving loads and towing. Using a stiff single shock in the rear is ok but when push comes to shove and the shock is working hard it will fade and or, chop out bushes. Using two lighter shocks halves the workload of a single and consequently less fade and problems. Duals on the rear is a simple job that entails lengthening the lower bases and fit another original upper mount to the chassis.
The standard shocker bushes don’t last long under rough conditions and it’s better to use a bigger diameter bush and heavier backing washers to take the load. A good idea is to cover the leading edge of the rear shocks with 3/16 to ¼ Rubber insertion to protect the external case and bush area from damage by rocks.
Better diff bump stops or rebounds are in order. I use Toyota 4Runner units to give me a more progressive and controlled rebound under full depression.
Another Rangie thing is the BOGE ride leveller in the rear ‘A’ frame. The Leveller is supposed to level the truck when a load is put in the back and thus still retain a good ride when unloaded. Unfortunately the Boges don’t work for very long and then all they do is rattle. Mostly we remove the units and compensate with spring rates. The Discovery models did away with this unit from the word go and now some models have an improved version of the old air bag system to raise the vehicle – we have converted quite a few of the later Rover vehicles back to coils and the owners are very happy with the conversions.
That will do for now and we’ll have more on suspension and steering mods next time.
Dennis R Trigg. O.A.M. J.P. MIAME.