My 4WD course – have to change some of my in-grained driving habits!

I think I learnt some pretty important tips during this two-day course – mainly about driving defensively... applicable to any car. Perhaps the licensing system does have to be re-vamped in Australia – because a fair bit of the stuff we were taught seems to be out of date and misleading (at least if the course teachers were correct – and they seemed to know their stuff). (nb. My terminology following is probably incorrect at times– not the fault of the instructors!)

Lesson No 1: Don’t go step-by-step down through the gears when decelerating

Why:

1. Braking technology has improved dramatically and brakes are now much more efficient at braking than using the engine through gear changes.

2. Using gears that way is much more expensive in the long run as clutch replacements are much more expensive than brake pads.

3. If you are worrying about changing down through the gears when you approach a hazard (anything that makes you slow down) then you have less attention to the road and one hand off the wheel.

Best method: brake and clutch at the appropriate time, and slow to appropriate speed for the hazard, then change into the appropriate gear for that speed just before you enter the hazard zone.

Lesson No 2: cornering technique.

The teacher got us to choose one of the following scenarios for negotiating a corner as our preferred approach:

‘a’ is your speed as you start your turn;
‘b’ is your speed at the apex of the corner;
‘c’ is your speed when you have finished turning.

Select from the following (the actual speeds are not the issue – it’s the relationship between them that matter in this exercise)

Scenario 1:
Speed at point 'a': 25km, point 'b': 30km, point 'c': 35km
Scenario 2:
Speed at point 'a': 25km, point 'b': 25km, point 'c': 35km
Scenario 3:
Speed at point 'a': 30km, point 'b': 25km, point 'c': 35km


The teacher asked us to add a different scenario if we didn’t like any of these – but most of us were happy with either scenario 1 or 2. However -

The correct answer is:

Scenario 4:
Speed at point 'a': 25km, point 'b': 25km, point 'c': 25km

The speed you enter the corner at is the same speed that should be used throughout the entire corner! Acceleration should only begin at point 'c'.

Why:

1. Centrifugal force makes the car ‘want’ to continue in a straight line. The front wheels are going to follow the turn you put them through, however it’s the back wheels which are more likely to want to continue in the direction they are already going. As you turn the car’s weight will ‘lean’ towards the outside of the vehicle, which means that two of the car’s wheels will be doing more of the work of maintaining traction, which means they have to work quite hard when compared with straight line driving.

2. If you are braking during the turn (like scenario 3), the car’s weight will move towards the front of the car. This means that your front tires will have better traction – however the rear tires will lose some traction – and there is a higher chance of the tail ‘spinning out’. (And noting that combined with point 1, only one of the front tyres (the outside one) will have the greater ‘weight’ of the car on it).

3. If you are accelerating during the turn, your car’s weight shifts to the back of the car; your rear tires will have great traction, however the front will lose some grip – which reduces the steering capacity which means you have a chance of your front tires not making the corner and sliding out.

4. Obviously these things are much more a concern on bad road conditions (like off-roading); but the point is if it’s your habit all the time you will be much better prepared for unexpected problems etc.

Lesson no. 3: Getting out of a skid or slide

a) Remove the ‘cause’ of the problem – usually either acceleration or deceleration combined with turning is what caused the skid or slide. So, foot ‘off’ the brake or accelerator (whichever you were using at the instant the problem began).

b) Point the front wheel in the direction you want to go. A lot of people try and fix this problem by pointing the wheel in the opposite direction of the slide, or else in the direction of the slide – but we still have to navigate the corner safely – and get traction back as fast as possible.

c) Use all available road width – eg aim for close to the edge of the road, or else use the second lane if you are sure it’s safe; rather than attempting to stay in the middle of your lane. This reduces the other major cause of the problem – the turn.

Lesson no. 4: Straight-line emergency braking

Most of us were taught that any sort of skidding/lock-up while braking was very bad and we should try to avoid it during an emergency brake. The technique we were taught was ‘threshold braking’ which means that you press the brake to the point as near as you can tell is just before the point the car will start skidding; as you slow down you can progressively increase the pressure on the brake pedal.

The technique we were taught in this course was quite different. The information we were given was that threshold braking is quite inefficient – most drivers don’t have much idea what the braking threshold of the car is (or feels like) – and when you add in complications like different surfaces it becomes very difficult to calculate in a split second. However, it is true that an uncontrolled skid is a problem, because a) you lose steering control, and b) when the wheels lose traction they don’t stop as quickly.

The answer is we try to replicate exactly what an ABS braking system does (but a lot more slowly). First, hit the brake as hard as possible. Then, when the car starts to skid, we start to pump the brake (fully off, then fully on), as quickly and regularly as possible. This way we regain steering control and we stop the car with maximum braking efficiency. Each time our brake goes on, the weight of the car goes forward and multiplies the braking effect, then we get traction back and repeat.

This technique works when we don’t have to steer much – a veer is possible. It is still bad to swerve to avoid a kangaroo – best thing to try for is to veer so that the kangaroo gets caught on the corner of the car rather than the centre (to minimize damage/danger).

We tried this out about 10 times on a dirt track – so much fun!!! So much easier than trying to ‘imagine’ the braking effort required to almost but not quite go into a skid... but it still takes a fair bit of practice til it can become ‘automatic’...

Nb. Even on a straight road, the back could slip out if the road has a curved surface...

Lesson 5: 4WD's can go over crazy hills without even feeling like they are going to fall over!

Technique: Low Range First Gear 4WD mode, stick the vehicle in first and keep your feet off the brake/accellerate the entire slope. Just steer. Navigate as close to 90 degrees to the slope as possible.

wow!

Lesson 6: 4WD's can go through some crazy mud/water terrain and not get bogged.

And then, they can still get bogged. And then, you can get them out with a bit of fun if you have another car and a snatch-strap. Or a winch (but that's not as fun).