pgjonker.co.za

[Adapted version of Johnie Jonker’s winning letter in Leisure Wheels, November 2009] 

I read with interest the article – Traction Control: How to use it – in the October issue of Leisure Wheels, especially where it was stated that momentum is not to be confused with speed.

For the first time in a SA off-road magazine, this is accurately put, as this concept is mentioned in every “How to” article on sand driving, but more categorically stated as: Momentum is not equal to speed.

Being an engineer, I find this statement extremely annoying, because technically, it is exactly that.

The equation for momentum: M = mv, where M = momentum, m the mass of the object and v the velocity thereof, implies that, as the mass of the vehicle cannot change (except marginally as fuel is burned), the only factor which can influence the momentum, is the speed. So momentum is indeed equal to speed (multiplied by a constant).

Generally, most readers understand that what the writer means is “keep moving”, so the gist of the advice is not lost – it’s just nice to have it expressed correctly. Thank you for that.

In the same issue of Leisure Wheels under Your Opinion, Leon Görgens laments the lacking magazine content for SUV owners. This, in my opinion, is because SUVs are barred by tour operators from many passable routes, artificially claiming exclusivity for the hardcore offroader, mostly using the undefendable excuse of “low range required”. So there is in actual fact, very little to report about on the topic.

This in spite of the general consensus that (some) SUVs can actually do much more than the average owner uses it for, although it may take more care (skill?) on the part of the driver. As a fellow SUV owner, I also long to do routes advertised as only for 4x4s with low-range, and has come up with the following “what if?” concept:

Assume an SUV owner wants to do the Solitaire/Walvis Bay desert route. As long as the SUV is one of a pre-selected number of models, based on e.g. standard ground clearance and rim size, and the driver has done a recognized offroad course – one that teaches the capabilities of the vehicle and how to coax this ability from it – it is allowed to join the convoy with the following additional provisos:

1) Should the vehicle be unable to cross a specific stretch of the route, it willl be escorted back or along a bypass route, rejoining the group later – the escorting done by one of the a SUV “tour managers”.

2) If an unexpectedly deep section of sand cannot be crossed due to lack of ground clearance and a bypass route does not exist, the tour manager will replace the nowadays standard SUV 65 profile tyres with 75 profiles, giving an instant 20 – 25mm lift. As most recent SUVs have 16” or 17” wheels, it is not impractical for the lead vehicle to carry, say, two sets of each rim size, to be swopped back on reaching the final destination.

If the route is planned carefully, the steep, rocky bits will all be downhill, so no low range would be required – just care.

Yes, it will cost more because it requires more personnel and two guide vehicles and may take more time than the standard expedition and a “no hurry” attitude from the guide, but it can work – and if somebody does not do this by the time I retire (you have 4 years), perhaps I should consider a scheme like this, run in collaboration with one of the existing tour operators. The bottom line is, you must get someone that wants to offer such a service to do it, rather than an also-ran.

The only problem I see, is that the owners of pucker off-roaders may be a bit disappointed once they realise that instead of their expensive vehicle, all they needed was a 2001 Subaru Forester …..

JJJ 

PS I can only applaud Francois Rossouw for “taking a chance” with the Terios in a recent Angolan tour. And also Don Nieuwoudt of Westcoast 4×4, who allowed me to do the Saddle Hill/Spencer Bay tour from Luderitz in my Forester a few years back.