SUVs and crossovers are getting more and more popular today. Even those vehicle manufacturers who initially didn’t plan to include 4x4s in their model ranges now produce lots of different SUVs – BMW X3 and X5, Porsche Cayenne, Audi Q5 and Q7, Volkswagen Touareg – these are only few of them. Many all wheel drive vehicles of the “new generation” are equipped with such devices as automatic speed support system, temperature adjuster, active suspension that are included in the standard equipment (this is not a full list of devices). The power characteristic seems to be the most upgraded – for example, Porsche Cayenne Turbo has 450h.p. and 620Nm torque what allows it to excel the majority of all wheel drive vehicles at speed and dynamic characteristics.
Tires must correspond to the increased power of these new cars. That’s why requirements to their performance have considerably changed. Some years ago many 4x4s were equipped with 15- or 16-inch wheels of 80 or 70 series with “S” (113mph) or “T” (118mph) speed rating letter. If we consider Porsche Cayenne Turbo as an example, its standard wheels are 8Jx18 with 255/55R18 tires and “Y” speed rating letter (186mph). Of course, for such SUVs there is always a possibility to replace standard wheels and tires with 20- or even 22-inch ones.
The increased power of the vehicles has made tire manufacturers adjust to the new requirements. They had to change the design of tires cardinally. The majority of tire manufacturers split their 4x4 model range into different categories according to the vehicle type and its application sphere. For example, a high-power vehicle is used primarily on roads and needs relatively noiseless comfortable tires if to compare with the earlier SUV model that is operated exclusively in off-the-road conditions. As a rule, one can name the following categories of all wheel drive vehicles:
• On-road
• Off-road
• Winter
Development and diversification of the AWD vehicles market requires further division of the three categories into subcategories as pointed below:
• Performance – high performance vehicle, 100% operation on road.
• Luxury – premium all wheel drive vehicles, high level of comfort
• Terrain – operation in road/off-the-road conditions
Winter tires are special tires that are produced primarily for the European market. Winter tires are intended for the operation at extremely low temperatures and will have performance and production mode that differ from “regular” tires for off-roaders. Such tires have studded tread rubber, special drainage grooves and even holes in the tread that allow to use studded tires on the ice. Below are the typical examples of winter tires (Bridgestone and Michelin) that have been developed exclusively for winter conditions and ice-covered surface.
All wheel drive vehicles can be divided into four categories:
• SUVs – Freelander, etc
• Premium sport/off-roaders – BMW X5, Porsche Cayenne, etc
• Pickups (functional/intended for recreation) – Ford Ranger, etc
• Vehicles/station wagons with off-road performance – Subaru Forester,etc
Tire categories
Road: performance
Tires for AWD vehicles are intended for the operation on road and are extremely popular today. Such vehicles as BMW X5, Porsche Cayenne, Volvo XC90 and others require from tires the capability to withstand big load. Some time ago it was necessary only for high-power road vehicles. The tires must provide the same performance as regular vehicles have while mounted on heavy 4x4s. At the moment the tires for such vehicles use directional tread pattern, high-quality rubber compound, etc
High performance road tires use aggressive directional tread patterns that provide traction both in dry and wet weather conditions. The effectiveness in off-the-road conditions and snowy weather will be restrained – but it is not so important for vehicles operated mainly on the asphalted surface.
Road: premium
Tires for “expensive” off-roaders are intended primarily for on-road operation like all high performance tires. The main difference is that the vehicle equipped with such tires requires higher performance and increased comfort level – low noise level and absence of vibrations. The tires of this segment (Lexus RX, etc) use less aggressive tread pattern and smaller tread blocks that are designed in a way that allows to reduce noise and vibration level thus ensuring quiet comfort riding.
Road: terrain
Although words “road” and “terrain” may seem as something incompatible these tires are intended for the vehicles that operated primarily on road surface but can sometimes be used in off-the-road conditions. Such tires provide comparatively noiseless and comfort ride if operated on the asphalted surface but are characterized more as off-road tires than the two first categories.
Off-road
Of course, requirements to off-road tires will considerably differ from those to road ones. Comfort and noise level are still important but don’t have a priority. While high effectiveness on dry surface and comfort are main requirements to road tires, off-road tires are to provide excellent traction performance in different weather conditions. It may be dry, muddy surface, deep slush or something average. Many leading manufacturers design a range of tires suitable for such conditions. Tires for off-road use feature wide asymmetric tread patterns, more solid carcass construction (to resist adverse environmental conditions and tire compression connected with off-road use) and cut-resistant rubber compounds.
Off-road tires can be divided into two categories – All Terrain (multi-purpose) and Mud Terrain (all-season). As a rule, all-terrain tires have wide tread pattern (if to compare with road tires) and tread design resistant to harmful impacts when driven on road. Mud terrain tires usually have the widest tread pattern. The pattern is directional what facilitates tire’s self-cleaning properties. It is obvious that the aggressive tread pattern of mud-terrain tires can be used on road surface but they will be hardly recommended for such use because of high noise and vibration level – just imagine tractor tires!
Off-road tires All Terrain in comparison with Mud Terrain (BFGoodrich):
 
If You want to achieve great results when driving Your AWD vehicle, it is important to determine which tires suits Your vehicle better. If You are in doubt just look at the offers of vehicle manufacturers. They know market segments well and will equip a new vehicle with the corresponding tires.
Road tires with high performance (as the above-mentioned) will be very effective on the surface for which they are intended. If You place them in adverse off-the-road conditions Your 4x4 will be put on a tough trial. Vehicles for which such tires are intended can work in off-the-road conditions but in this case their effectiveness will considerably fall.
Off-road tires such as Mud Terrain are very effective in off-the-road conditions. They are very popular and are used both for recreation and racing events. But if You use such tires for long highway trips You will soon understand why they are not recommended for constant trips on the asphalted surface.
As it was mentioned above, winter tires were created exclusively for the operation at extremely low temperatures and are used primarily in Northern European states.
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