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Frequently Asked Questions |
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In general, approximately 50mm (2") lift over standard is legal. A lift any higher than that will require modification to your vehicle. |
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What is a deep-cycle battery? |
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A deep-cycle lead-acid battery is designed to deliver a consistent voltage as the battery discharges. In contrast, starter batteries (e.g. most automotive batteries) are designed to deliver sporadic voltage spikes. Battery-driven vehicles, such as golf carts, forklifts and floor sweepers commonly use deep-cycle batteries. While a deep-cycle battery can be used as a starting battery (and may work better than a traditional starting battery with the myriad of electronic components attached to most modern vehicles), the lower "cranking amps" imply that an oversized battery may need to be used in an older vehicle that lacks fuel injection. The key structural difference between deep cycle batteries and cranking batteries is the Lead plates, which are solid in deep-cycle batteries and composed of porous sponge-like plates in starting batteries. Some batteries that are labelled "deep-cycle" do not possess these solid lead plates, however, and are actually "hybrid" batteries. While a deep-cycle battery is designed to discharge down to as much as 20% of its charge capacity over several cycles, companies recommend that a hybrid battery not be discharged beyond 50% of its capacity. |
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A gel battery (also known as a "gel cell") is a rechargeable valve regulated lead-acid battery with a gelified electrolyte. Unlike a traditional wet-cell lead-acid battery, these batteries do not need to be kept upright (though they cannot be charged inverted). In addition, gel batteries virtually eliminate the electrolyte evaporation, spillage (and subsequent corrosion issues) common to the wet-cell battery, and boast greater resistance to extreme temperatures, shock, and vibration. As a result, they are primarily used in automobiles, boats, aircraft, and other motorized vehicles. These batteries are often colloquially referred to as sealed lead-acid (SLA) batteries due to their non-leaking containers, but they are not completely sealed; the valve regulation system allows for gas to be expelled. Chemically they are the same as wet (non sealed) batteries except that the antimony in the lead plates is replaced by calcium. This preserves the mechanical characteristics but renders the construction far less prone to gassing. The battery type is often referred to as a Lead-Calcium battery. |
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What type of battery should I use? |
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Normal deep cycle batteries are not suitable for winching or starting purposes. With the more expensive and stronger constructed, composite paste marine batteries, a longer battery life and satisfactory winch performance are assured. Choose the deep cycle battery when you require long-running power and low current drain with the added peace of mind of knowing your battery will last – charge after charge. Unlike cranking batteries, deep cycle batteries provide sustained power over extended periods of time and are designed to be repeatedly discharged and recharged. |
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What is a dual battery system? |
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Auxiliary Batteries are used to operate appliances while you are away from mains 240v power, and so that you don’t run the risk of compromising you vehicles main starting battery. An Isolator is required to enable the charging of the second 'auxiliary' battery, but at the same time isolate it from the main battery system in order to protect the main battery from discharging into the same electrical circuit - usually the auxiliary battery is connected to a fridge, winch or caravan electrical system. |
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All vehicles have a differential, commonly referred to as a "diff". It allows the powered wheels of a vehicle to be driven at different speeds in order to compensate for the different distances they have to travel when negotiating a corner. 4wd vehicles require either two or three differentials in order to allow all 4 wheels to travel different distances. Therefore 4wd vehicles will have a differential between each pair of wheels and also, in the case of a vehicle which has permanent 4wd, between the back and front axles.
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What does the differential do? |
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The differential alters the amount of power directed to each pair of wheels on an axle. More power goes to the wheel which has to travel the greater distance. This is the wheel which is on the outside of the curve being negotiated. |
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What is a 'limited-slip' differential? |
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A limited-slip diff is a type of differential which uses either fluid or mechanical mechanisms to control the amount of power being directed to a particular wheel. When a wheel loses contact with the ground, a standard differential will transfer all power to this wheel and none to the wheel which remains in contact with the ground. This means this axle is no longer effective in driving the vehicle. The limited-slip diff reduces the amount of power going to the wheel which is no longer in contact with the ground. This allows the other wheel to retain a varying degree of efficiency depending on the type of limited-slip diff. |
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Can I use 4wd on the road? |
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Permanent 4wd vehicles obviously use 4wd on the road. A differential on the drive shaft connecting the front and rear axles will enable this to be done safely with no adverse affects on the vehicle. In a selectable 4wd vehicle the lack of a centre differential means that 4wd should not be used on the road. When 4wd is selected the front and rear axles are locked together and therefore the front wheels, which usually travel greater distances, will have to 'lose' some power somewhere. This is done by the tyres slipping on the road surface and is obviously detrimental to the tyres. If the tyres do not slip and do the work of a differential then "wind-up" may occur.
Having said that using 4wd on the road is inadvisable it should be noted that periodic use of 4wd is recommended to avoid the transfer box, differential and wheels hubs from "drying out". If you use the vehicle regularly off-road then there is no problem but a lot of people buy 4wd vehicles and they never see a muddy track. In this case 4wd should be selected in order to circulate oil around the unused parts. If this is being done "on the road" then only do so in a straight line. This will avoid "wind up" and/or damage to the tyres. It is usually recommended to do this at least twice a year but as long as care is taken when doing so it cannot be done too frequently. |
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This is where torsion, or twisting force, is applied to the drive shaft and gear box of a selectable 4wd vehicle because the front and rear axles are rotating at different speeds and there is no central differential to equalize these differences. When driving off-road, on soft surfaces, slippage of the front types will dissipate these forces and wind-up will not occur. If the tyres cannot slip sufficiently and wind-up does occur, then the amount of torsion that can be applied to the drive train, which is fairly limited, means that eventually it will "lock up" and further progress will be impossible. |
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What is the "approach angle"? |
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Sometimes also known as the "take off angle", this is the angle of slope which can safely be negotiated by a 4wd vehicle. That is to say, the angle between the slope and an imaginary horizontal line. It applies to the front of the vehicle and defines the number of degrees of slope that can be attempted by the vehicle without any damage occurring and the front wheels losing contact with the ground. The angle differs for various 4wd vehicles and can usually be found in the owner's manual. |
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What is a "transfer box"? |
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This is the secondary gearbox which allows power to be passed to the second axle on a 4wd vehicle. Selectable 4wd vehicles will have a second gear lever which controls the transfer box and disengages power to the second axle. Permanent 4wd vehicles also have a transfer box but it is permanently engaged in drive. Nearly all transfer boxes allow the selection of either high or low ratio depending on the condition of the terrain. |
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The Global Positioning System (GPS) is a system which uses satellites to pinpoint your exact location, to within a few feet, and displays your position on either a hand held or dashboard mounted display unit. Sophisticated units can overlay this position on a map display whilst less sophisticated units only show the longitude and latitude which needs to be cross referred to a suitable map. Other useful features are the ability to record the route being driven for later use or for backtracking. They can also display useful landmarks, average speed, current speed, altitude, sunset, sunrise and time remaining to destination. |
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What type of tyres should I use? |
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Selection of tyres depends greatly on the type of use they will be put to. Off-road tyres do not perform as well on the road as road biased tyres and vice versa. Most 4wd vehicles are used predominantly on the road and therefore road biased tyres should be selected. How much of a bias will depend on personal choice and how much off roading is undertaken. Just remember that performance of off road tyres will be substantially less than road tyres. Care should be taken not to get caught out and have an accident due to underperforming tyres. The best solution to this problem is to have two sets of wheels. One with road tyres and the other with off road tyres. The correct set of wheels can then be fitted for the type of driving you expect to do. |
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FAQs