A while back I was driving past a garage and they had a Chinese import agricultural buggy for sale. They were selling up and just wanted to get rid of it. It was brand new and not even registered. After a bit of haggling I ended up buying it.
Of course the first thing I did was take it off-road to play. It wan't even registered yet but I had to play. Of course I almost immediately smashed one of the spot lights on a tree branch. Those spots are too vulnerable. I suppose most people would be upset by breaking a light on their brand new car with 2 miles on the clock but I just laughed and carried on.
First impressions: It's a little under powered and the suspension hardly moves at all. It limits travel off-road and is very harsh. Suspension is key with off-roaders so that will have to change! Right, let's get it in the workshop and take a good look at it. First of all that big tipper body will have to go - it is vulnerable to damage and adds a lot of weight. Weight is an important factor off-road. It also needs some extra reinforcement on the roll cage and more body protection.
This is one of the
'rock sliders'. It protects the vehicle from rocks and allows you to
slide over obstacles rather than getting them jammed behind the wheels.
Another view, also
showing one of the roll cage braces.
I extended the
nudge bar to wrap around the bonnet and protect the headlights. On the
roof I added extra rails each side. These are useful if you are jammed
up agains a tree sideways. They protect the fibreglass roof and slide
easily without damaging the tree.
I noticed that the
lower rear wishbones are curved. As they are symmetrical I wondered if
they could be turned upside down. With a small amount of modification
with my favourite big hammer they do fit on upside down. As you can see by
the picture, this improves ground clearance quite a bit. The bracketry
will have to be cut off and moved to the top but that is no big issue.
Next it was time to take a look at that suspension. Those springs are massive! They would hold up a full size truck. I set up a simple ramp and tried driving up it. With the standard suspension it only got a few inches off the ground before running out of traction.
idea - add a rocker between the shocks. As one wheel goes up it pushes
the other down. This makes a huge difference but if I allow lots of
travel it is possible to over extend the suspension and damage the
Time to start getting creative. I used air suspension on my trials car with considerable success so I decided air was the way to go here as well. Air has a number of advantages over coils. First of all it is lighter. Secondly it provides 'rising rate'. Conventional springs are roughly linear. If 20kg compresses the spring 1cm, 40kg will compress it 2cm and so on. Air springs get progressively harder as they compresses. This means that the springs are very soft over small bumps in the ground giving a smooth ride and maximum grip, while avoiding bottoming out over big bumps. Of course if you link the suspension units together you can play clever tricks with balancing the weight across the wheels.
Of course you can't buy suitable off-the shelf air suspension units so I had to make my own. Using a tried and tested design from the trials car I ordered up a set of custom made long travel adjustable shock absorbers and fitted them inside some Range Rover air suspension units. This resulted in the air equivalent of coil-overs. This page documents the conversion process.
Now this is more
like it! I don't like those top mounts and the suspension units get in
the way of the rear roll cage stays but this certainly shows promise.
After much head
scratching I worked out a way of mounting the shocks to the lower
wishbone. This allowed the top mount to be welded to the roll cage
brace. A much neater solution!
Fitting the shocks
on the front was easy - just relocate the top mounts upwards and they
bolt straight in. In operation there will be a valve between the shocks
allowing me to cross-couple the shocks, giving a similar effect to the
original rocker system I experimented with. With both front and back
valves open there is virtually no roll resistance and the vehicle tips
over just with the weight of the driver.
The only worry is
that clearances get a bit tight near full compression. At full lock and
full compression the wheel hits the brake master cylinder. For now I'll
just make it a rule to avoid full lock and full compression...
This looks more
promising. I ran out of travel on the jack before reaching the limits
of the suspension. I have nearly 12" of travel at each wheel.
As I have scrapped
the rear tub I need to add mudguards. Mudguards are very vulnerable and
I don't want to have to replace them every few weeks so I ended up with
this solution. The matt finish part is half a polypropylene lorry
mudguard, cut down the middle. The shiny part is 1.5mm thick
polypropylene sheet that has been welded on. I'm still learning plastic
welding so the welds are a little wobbly.
As you brush past
a tree the thin plastic just flexes out of the way and bounces back. I
like polypropylene. It is easy to weld and very tough
For some reason
the left hand mudguard sags a bit. I'm not sure why. They still need a
bit of trimming and finishing but they look like they will do the job
This is a rack to
mount two 'waffles' (light weight fibreglass boards used for bridging
gaps etc) and the obligatory hilift jack. Hilift jacks have a multidude
of uses and are extremely useful off-road. The rack will have a sheet
steel floor underneath it to prevent trees or rocks getting jammed in
Time to squirt
some paint on it. Two coats of etch primer and two coats of 2-pack gloss black. Now that looks better!
It looks like it
means business! The first test run was at a 'scuffle' - an off-road
drive-what-ya-brung type event. I was up until the early hours of the
morning finishing it off. I did get some odd looks for bringing a brand
new vehicle. Most of the others there were, er, 'well used'
It looks promising.
Nothing broken after a couple of goes around the circuit. The
suspension shows a tendancy to slowly collapse as the air suspension
units are only held on with temporary clamps and slide down the shocks.
I was also getting some worring grinding noises from the back
Oops, I spoke too soon. The grinding
noises were rocks getting jammed between the brake calipers and the
wheels. Eventually one of the rear wheels cracked under the strain,
letting out all of the air. No more playing today. Unfortunately this
breakdown was the start of a trend. This car likes breaking.
On topart 2 - sorting out some of the issues discovered on this event.
Do you like what I am doing? Am I doing it all wrong? If you have any questions or suggestions, do let me know by posting a comment.
Note: Spammers and trolls will be shot!