Domain

Explanation

What is off-road?

• In urban environment, for speed, safety & preservation, paved roads are constructed & maintained for the heavy traffic of all vehicles to travel on
• In rural environment, the type, intensity, frequency, speed & other attributes of the rural traffic often do not warrant fully paved & maintained roads – thus, the conditions of roads are often poorer being less comfortable to travel on - Unpaved roads
• Paved roads are of two major types – rigid pavements & flexible pavements
• Rigid pavements, as the name suggests, are high strength, high stiffness paved roads that do not deform much under heavy traffic loadings – thus spreads the traffic load more evenly to the ground below – less maintenance but more expensive & slower to construct
• Flexible pavements are often constructed by layering from the bottom (with the most readily available & cheapest materials like rubble or coarse aggregates) to the top (wearing course – often durable tarmac or asphalt with high wearing & abrasive capacities, but most expensive & used thinly) – less stiffness, hence deform more readily under traffic wheel axles & concentrates more deformations to the ground below, thus the need for coarse aggregates to form stiff barrier
• These paved roads serve to cover up volatile, weak & uneven ground conditions which are engineering headaches, aesthetic failures & enemies to comfort
• Ground conditions can become so severe as to obstruct traffic – flood-prone (need drainage inside, below & beside pavements); muddy – too slippery & easy to get stuck (need drainage to clear trapped moisture & hard, stiff surfaces to ride on); rocky – prone to sudden slips (rock slides), punctures & hard knocks (need to level out sharp edges & cohesion to hold the separated pieces together)
• We would not like to travel such poor unpaved grounds
• I think only two types of people who ride on these grounds – the unwilling but have no choice (no money, no chances) & the willing
• However, there is one group of people who not likes these ground conditions, but actually makes, maintains & tests their special vehicles to traverse through such harsh terrains
• This type of vehicle is the 4x4 (4 wheels with engine power transmitted to the 4 wheels) - a bicycle is a 2x1 (2 wheels with only the rear wheel turning by the legs)
• This type of driving is off-road driving
• To my humble knowledge, this is no official name for these people
• Maybe we should give a name of this group of people – offroaders

Off-road driving

• The first thing to notice about off-road driving is the potential dangers – the vehicle might fall over, u might fall over or the both of u might get hurt
• It is not only sufficient, but absolutely necessary that off-road driving be done together with a group of people with a group of 4x4's - never venture alone in single 4x4 (remember how the loners are always end up in thriller & horror films)
• If u are unwilling, but left with no choice, go for the sturdy machine – the 4x4 - & pick useful techniques & experience – u have to survive, remember
• If u are willing like the offroaders, the 4x4 is probably in suitable conditions for the terrain, go for the skills, techniques, experience & thoughts about such travel – take it like an adventure when u are dying to challenge & find out what’s over that impossibly steep ridge
• It is really a test on both man & machine
• The driver man has to have or gradually pick up the necessary adaptation, skills, techniques, experiences & mentality towards all driving conditions, weathers & terrains
• The 4x4 machine has to be equipped properly, sufficiently & sometimes abundantly in order to be perfect for expected conditions, yet robust towards unexpected conditions – the least thing u want is a breakdown, stuck, trap or overturn that u are not equipped to handle
• Different 4x4 require different skills, different skills apply for different 4x4 & terrains
• Trying in different ways – some nominal, others new – is actually lots of fun
• So have fun trying & try funnily, but safety

The 4x4

• According to the author, here’s an overview of the historical development of the 4x4:
• 1904: Spyker company built what is considered the first 4x4
• World War I: US-built Marmon-Herrington four-wheel drive truck – "the granddaddy of the Jeep "
• 1940: ¼-ton 4-wheel drive (4WD) vehicle – the ubiquitous Jeep – first constructed by Willys (Willys Jeep) in US
• 1948: Land Rover by Maurice Wilks of the Rover Company
• 1940s-1970s: 4x4 mostly used for work
• 1970s-: leisure use of the 4x4 picks up
• 1970: British-designed Range Rover that combines the luxury of a car (saloon – not those hair-dressing bars called salons) & the all-terrain capability of a 4x4
• Present: ubiquitous use of 4WD & 4x4 with balance on leisure & off-road
• Put a saloon beside a 4x4, there would be noticeable differences
• The obvious is the saloon is only on-road, but 4x4 is all-terrain (both on & off-road)
• In fact, a typical 4x4 (there are hundreds of different kinds & makes, but certain qualities stand out as common) would have the following differentiating characteristics:
• Engine: the engine torque & power are concentrated towards lower revolution at lower gears – a saloon would aim for maximum torque at the highest rpm (>4000 rpm), but a 4x4 would aim for the max. torque at <2000 rpm – the reason is that off-road conditions necessarily requires a slow, powerful pace, thus an engine that provides this; as such, handling a 4x4 is very different from a saloon – don’t think u pass a driving test, u can also drive a 4x4 across the same course
• Gears: more gears & levers in 4x4 – (1) for on-road conditions: normal gears (high ratio); (2) for off-road conditions: low gears (low ratio); in fact, I’m quite taken aback by the sight of two gear levers! It’s like a two-headed snake
• Transfer box: to switch between the high gears (on-road) & low gears (off-road), switch between the available drive systems & other proprietary variations to suit different needs; typically the transfer box makes clicking sounds during switching – the author has indicated that once off-road, switch to low gears
• Chasis & Bodyworks: a stiffer, higher & rugged chasis (support frame of the 4x4 like a skeleton for the body) to withstand the harsh terrains; tougher, harder & more durable bodyworks & finishes to withstand unavoidable knocks, scratches & dirt; protective items like front guards, winches & even an extra wheel hung at the back are typical
• Wheels: the wheels are larger, higher with much deeper, thicker tyre threads & patterns; the suspensions are stronger & longer – to withstand the impacts & shocks as well as to lift the 4x4 further off the treacherous grounds like sharp rocks or mud mounts; minimal front & rear overhangs (how far the edge of 4x4 bumper hangs in front of the edge of the wheel
• The 4WD system should be explained to clear confusions
• According to the author, 4WD means that all 4 wheels have power transmitted to them – that is, every wheel would move when the accelerator is pressed
• The recommended accessories:
• Basic kit: ropes, kinetic energy recovery rope (KERR), shovel, tree strop, bow, toolkit, first-aid kit, fire extinguisher, canvas bag
• Hi-lift jack
• Exhaust air jack
• Ladders: not for climbing, but for bridging across holes
• Ground anchors
• Off-road tyres: deep treads, choose suitable tread pattern (remember the tyre wars in Formula 1)
• Roll cages: to guard against severe rolls & crashes
• Locking axle differentials
• Suspension modifications
• Winches: hand or mechanical – for recovery from stuck or trapped positions
• Roof racks: for dry goods not to be soaked in water
• Fuel & water tanks: for long-distance & hot conditions
• Maps: to guide like GPS
• 4x4 modifications: modify & upgrade, but keep to legal limits
• The thing to note is that know the terrains & tailor-make the 4x4 for them; if u already have one, pick the terrains that it is suitable for
• Terrains = 4x4

4WD system

• 4WD can be classified under 2 categories:
• Part-time 4WD: when on-road, use the normal 2 rear wheels only (4x2); when off-road, can switch to all 4 wheels powered (true 4x4); advantage of better on-road use; disadvantages of loss of power (when >1 wheel loses grips – this is due to the presence of differentials (two axles, two differentials) that enable wheels to turn at different speeds to round corners, but power gets transmitted to the wheel(s) that turns fastest – like a stiff member would attract more vibration energies & vibrates more) & using 4x4 for on-road results in wound-up (front axle at different speed from rear axle – solution: jack up to let the wheels turn freely)
• Full-time 4WD: 4x4 to both axles under all conditions; advantage of no winding up of axles (through the use of a third differential); disadvantage of power transmission due to the 3 differentials (solution: incorporate a center differential lock to get performance of a part-time 4WD)

The driver

• The driver likes to be adventurous, vigilant, careful & skilful, all at the time
• Right speed & momentum is crucial for successful off-road
• As off-road guru David Bowyer puts it: "As slowly as possible & as fast as necessary"
• In other words, always go slow (at low gears – two low) & only speed up when required (as in muddy conditions)
• Choose the right gears for speed, so know the ins & outs of your own 4x4
• Take it step-by-step, pick up gradually & surely
• Advices: (1) never hook thumbs inside the steering wheel (known to break thumbs under sudden jukes); (2) retract radio aerials & almost close all windows
• If stuck, use winches, ground anchors or even manual labour to get loose
• Inspect 4x4 after off-road session – for immediate fixes & subsequent maintenance

Techniques for different terrains

• For different terrains, different techniques are needed:
• Mud: lower tyre pressure to spread weight & get more grip; use higher speed & momentum to get across; never stop completely; use right gears; swirl left & right for tyres to bite the mud for better grip; straddle if ruts are too deep or middle section is too high; use deep treaded tyres
• Narrow ditches: don’t go perpendicular across the ditch – front axle gets stuck & front overhang crash; instead use the diagonal 1-2-3-4 approach – one wheel in the ditch at any one time (like dinosaurs walking with three legs always on the ground)
• V-shaped gullies: never drive with all wheels along one wall & the 4x4 is not level; instead keep the 4x4 horizontal at all times; it would be hard to get out if slanted
• Rocks: watch out for sharp ends both at the bottom & along the sides; beware of quick conditions (where the rock fragments suddenly slip & slide); use the lowest gear (first gear low) & always keep to the route taken
• Hill climbs: note front overhang is high enough; watch what’s over the hill (u don’t want a cliff – remember cliffhanger); choose the right gear & don’t change throughout the climb; second gear low is a compromise between speed & strength; keep steering to get grip; keep all 4 wheels on ground at all times (if front axle is lifted, traction & grip is lost – dangerous); slow down near to the top & prepare the down climb
• Hill descends: shift to the lowest gear (first gear low); forget the throttle (accelerator); use engine-braking only; never use foot-brake (the sudden jerk might start a nasty slide downhill): let gravity do the work
• Failed hill climbs: coming down safety when unable to hill climb; stop the 4x4 completely with foot & hand brakes; start up stalled engines; look back; keep steering wheel straight; avoid swirling steering; reverse gear & move slowly & carefully
• Water wading: first, avoid water & approach only when that’s the only way; water is not good for the engine & safety; if no choice, pick the shallowest route (remember still waters run deep); inspect how deep the water (Steve Irwin of Crocodile Hunter walk down the entire length of the crossing, planting branches to mark the depth); check depth is within 4x4 vehicle wading limit (normally about the wheel rim level; if exceeded, keep these sealed or above deepest water level: 1) engine air intake, 2) gearbox, 3) breathing tubes); protect engine by ensuring the air intake is always above the deepest water level; choose second gear low; once ready, drive through the water keeping two things in mind: (1) never stop (braking would sink into the mud below); (2) drive at such speed that a bow wave is created (up to level of rim & never over the bonnet); if 4x4 stalls in water, restart engine immediately & drive steadily

Final words

• Never venture alone, instead go as a group of people (to help out & keep vigilant) & 4x4's (for self & mutual recovery from immobilisations)
• Know yourself, survey the terrains, pick the right 4x4 & equipment (it's like all other adventure sports, u can never prepare enough)
• Research routes – focusing on suitability, safety & legality
• Be prepared – for the unexpected (hey, that’s what off-road about)
• Respect the terrain – the land provides this precious opportunity, treat it with the respect that it deserves
• Off-road USA
• Off-road driving
• Off-road rally
• Jeep Nation