Rob. The vehicle only carries 900lts of premix foam solution, and vehicle is very nippy indeed having used this type many yrs past its a very good rescue truck for crashed aircraft carrying up to 4 crew if needed.
Added by Bob Ewing on 17 October 2018.
It may not be overloaded in terms of total weight, although I still suspect it was. But the third axle which has been added on obviously does not have the requisite suspension characteristics to maintain an even keel when it is fully loaded.
Unlike the Land Rover, the Range Rover was never designed as a commercial vehicle, and if all the conversion involved was adding another axle and a second set of standard rear axle springs and shocks, it can be no surprise the back end is sagging.
The 4X4 Range Rover had a payload of only around 240 KG once the back seat was occupied, and it enjoyed close to 55/45 weight distribution. Add the extra bodywork, the weight of the third axle, frame extension, a pump and 900 KG of water, plus some equipment - all biased towards the rear - and this is the result. Still quite fast, but not a really well thought out design!
I have heard from firefighters who drove these that they were okay in a straight line but very prone to rolling excessively. This was presumably due to the high center of gravity of all that weight over the rear axles with their single tires and narrow track...
These are fine driven in straight lines! Had the pleasure of driving a Tacr 2 during the 1977 national strike around Sheffield and South Yorks. Although a good idea for an airfield this layout on a Range Rover was potentially lethal for driving in traffic laden cities. As Rob rightfully states it was overweight. Cornering needed great care obviously, give me a Land Rover in this layout and I would feel safe. There are a few genuine 6x6 around but the tyre wear on the trailing axle was terrible, they needed replacement after about two thousand miles. I remember Herts operating a six wheel Commando at Watford for a few years and they had the same experience.
At night, the headlights look as if they will come in useful for spotting aircraft, too!
Added by Rob Johnson on 16 October 2018.