We will issue an engineers report for the work that we do. If you have any questions please feel free to ask. I will use the "RUBICON" TJ that we built for Jeep UK as an example to demonstrate how to think the whole package through.
This vehicle was the brainchild of Barry Stallard of Jeep UK. The Wrangler TJ Sahara 4.0 manual, that was to become Rubicon 2 was the first one in the country. Once it had done the motor show and been shown to the franchised dealers, it was bought down to us and promptly ripped apart! Barry had a list of features that he wanted including in the design and between us we came up with what was then, a benchmark vehicle that 11 years on can still hold its own with most other vehicles out there.
Starting at the beginning it is important to have a plan and identify the areas that you wish to improve on the vehicle and having identified the area understand any other related problems or work that may need addressing. Another point worth considering is the type of on or off-roading you intend to do. There are lots of different types of off-roading and there is no one perfect set up that will do everything brilliantly. For example: If you intend to do slow axle twisting trials type driving, you will need soft compliant suspension. On the other hand if you intend to go racing you will require long travel firmer suspension and a lot more modification elsewhere.
The TJ Wrangler is by design quite low slung. Whilst this makes it low and stable on road, it can cause ground clearance problems off road. The first decision is how to raise the vehicle to give it better clearance underneath and decide how high you want to lift the vehicle and how you achieve this. Ultimately this will be a compromise. One way is to fit larger diameter tyres. This will lift it slightly and will also increase the gearing, as well as minor problems such as speedo accuracy (will require a different pinion) and fitting a larger tyre onto the spare wheel mount. You will not be able to increase the tyre size radically as the tyres will foul the body on full axle articulation. To get round this you will need to either raise the body up on the chassis or raise the suspension or both. The taller the tyre the taller the lift required and of course the higher the gearing and so it goes ...
The basic criteria for the vehicle was that it should drive well on road but have lots of axle articulation and ground clearance off - road. Whilst the TJ is not going to be raced it will have to put up with a fair amount of constant abuse when being driven by the motoring press. It would need to have maximum possible traction and be able to wade through rivers to a sensible depth.
