by Ian Johnson
PART 1
Here are some guidelines which should help. Practice, experience and caution all count for the safety of you, your passengers and those in other vehicles. Australia’s gravel roads are well known the world over, and are often said that it is like driving on ice; only worse!
- WRX driving on gravel.jpg (81.2 KiB) Viewed 5064 times
The [web photo] WRX driver above is ‘off’ after entering a gravel corner much too fast!
Of the ~800,000k of Australia’s roads, 60% are gravel, dirt or sand.
If you want to get to the best camping places you must get safely to the end of a gravel, dirt or sand road!
Pointers:
Every person in the car must wear seatbelts. Plan the driving day so that you do not become tired. Take a break every two hours or less. Pack carefully and know that weight distribution will have an effect on vehicle handling. There are 1,000 grams in a kilogram!
Remember, you are the driver of the vehicle, not the other way round; and you will effect the way the vehicle behaves, not the other way round. You are responsible.
The tyres you wear will effect the vehicle handling depending on the diameter, pressures, profile, sidewall strength, tread pattern, tread depth and age. This is a lengthy topic but generally there are often better tyre choices than the ones fitted when you bought the vehicle which are biased for on bitumen (H/T rating). In my opinion better tyre factors include stronger sidewalls, deeper tread, taller profile and A/T (All Terrain) rating. These will give improved response to steering, traction and braking off bitumen where conditions are hard on tyres.
Lower tyre pressures are suggested when off bitumen - say 15 - 20%.
The transition from bitumen to gravel, or the other way round, is often rough, stepped or guttered so slow down to check. Surfaces may vary suddenly and include corrugations, rocks, holes, gutters (like being held on rails), sand or bare.
Driving
Your attention is vital. Only drive to what you can see and feel.
You may feel sensations of floating, sliding or turning on an axis, but given experience, you will be able to accommodate and compensate.
Driving on our so-called ‘ball-bearing’ gravel may be likened to sitting in a chair on casters whilst being controlled randomly by a demented outside force! Take control, slow down and be alert.
The edges of a gravel road should be avoided as they may be very loose, sandy or rocky. If you are there, gently slow down even more. Getting near or off the edge is often the reason people lose control and have an accident or damage tyres.
In the middle of the road the camber is generally domed - sloping to both edges to allow water to drain away. Position your vehicle where it is balanced and easiest to control. The preferred place is in the most worn wheel tracks which usually have less ball-bearings. These bare areas give the optimum braking and steering. As a bonus this bald area gives the best gravel fuel economy. Any parts which have become wet, muddy or sandy require extra caution and attention. Observe.
PART 2
What if I understeer, oversteer, slide, weave side to side? All may lead to loss of control, but can be avoided by driving carefully. Look ahead, slow down, ‘read’ the road conditions, pay attention and smooth out your steering and braking.
Understeer (the front of the vehicle tends to go straight ahead when turning); and oversteer (when the rear of the vehicle tends to swing out); are both controlled by easing gently off the throttle and steering gently to compensate. If it is understeer, turn gently in the opposite direction. If you are driving a later model Subaru much acquired driving skill may ‘happen’ automatically via onboard computer systems such as ABS, VDC, EBD, ATV and X-Mode.
Read your owners handbook!
OFF bitumen; Cruise control OFF as you will need every millisecond to react.
Lower tyre pressures before you leave the bitumen which will reduce the possibility of tyre damage from stones and rocks. But remember hot tyres may already be at a higher pressure than when cold. Take out 15 to 20% of what they are actually at. Check them when cold and pump up for the bitumen.
Reduce speed because you may have been cruising at 100kph+ on a bitumen highway. It is suggested that you enter gravel/dirt/sand section at 70kph then slowly increase to, say, 80kph.
‘Read’ the road. Check your (reduced) speed, ‘feel’ your vehicle balance, read the road camber, wheel tracks, bends, changing surfaces, frayed edges, corrugations, holes, water, mud, animals etc.
Your traction will be at least half what it was on bitumen.
Braking distances will be considerably longer - alarmingly so for the inexperienced - close to double the bitumen distance. Brake smoothly, brake before corners, and use a light throttle through the corner.
ABS (Anti-lock Braking System) may give a strange sensation of pulsing or shuddering through the brake pedal which is normal. If you have not experienced your ABS in operation I suggest you be guided by an experienced driver at a suitable location. If you need to brake to avoid a dangerous ‘moment’, press hard on the brake pedal and steer smoothly in the required direction. Braking distance may be more with ABS, but vehicle control will be considerably higher than without.
Oncoming roadtrains and trucks are a hazard. I suggest stopping to allow them to pass as there may be other vehicles in the following dust cloud. The seconds taken is worth it! It might be time for a cup of tea!
I highly recommend attending an advanced or defensive driving course where you can do all the “What if I…” Ask before booking about gravel or wet surfaces, ABS braking, your car or theirs, out-rigger wheels (their cars) club discounts, group size & discounts. Google© similar to this – “advanced driving course perth site:.au”
Happy Gravelling! Ian J.
Graphic below from http://www.subaru-global.com/tec_vdc.html