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HomeMy WebLinkAboutThe Citizen, 2007-10-25, Page 20(MS) - Do you know that today all-wheel-drive (AWD) and four- wheel-drive (4WD) vehicles make up about 25 per cent of the car and truck market, with prediction for 50 per cent of the market in years to come according to reports by “Forbes”? For some that is surprising. It wasn’t very long ago that these drivetrains were reserved for a select number of autos, mainly Jeeps and commercial trucks. Despite the fact that the systems are typically heavier, and in turn make a vehicle less fuel efficient, the AWD and 4WD boom is continuing to make gains. All of this talk about four-wheel capabilities begs the questions: Just what’s the difference between the two? Aren’t they just one and the same? Actually, no. We’ll get to what makes these two drivetrains unique, but first, this lesson on torque, traction and wheel slip, courtesy of HowStuffWorks.com will be helpful. Torque:This is the twisting force that the engine produces and what moves the vehicle. The gears in a vehicle’s transmission and the differential multiply the torque and split it up between wheels. Lower gears provide more torque. Torque is also directly related to traction, meaning the maximum amount of torque that can be created is determined by the amount of traction, not by the engine. A car engine can be very powerful, but if the traction is not there, the car won’t move very well. Traction:A number of factors influence traction, including the weight placed on the tires. However, weight shifts as the car maneuvers. For example, when a car makes turns, weight shifts to the outside wheels. During acceleration, weight shifts to the rear wheels. The coefficient of traction also is involved. This is the relationship between the amount of traction between the tires and the road to the weight resting on each tire. The coefficient of traction can be changed based on the tire used for a specific type of road. For example, a large, knobby tire for off-roading in the mud would have more traction than the same tire on a dry, flat road. Wheel slip:This occurs when the force being applied to a tire exceeds the traction available to the tire. Force can be longitudinal - that which comes from the torque applied by the engine or the break, or lateral - that which is the force it takes for a car to change directions when driving around a turn. Here’s where 4WD and AWD come into play. In cars that drive four wheels you have the ability to double the amount of longitudinal force (what makes the car go) that the tires apply to the ground - improving traction in many conditions and reducing wheel slip. Scenarios where AWD and 4WD have advantages include snow, where most 2WD cars lose traction quickly; off-roading, where one or more tires may lose traction when crossing a stream, etc.; or when a vehicle needs to scale slippery hills. PAGE 20. THE CITIZEN, THURSDAY, OCTOBER 25, 2007. Sliding through Today all-wheel and four-wheel drive vehicles make up for about 25 per cent of the car and truck market. (MS photo) Gearing up for slippery road conditionsOOnn tthhee RRooaadd DAYMAK Fall Sale on all in-stock pocket and dirt bikes, 4 wheelers, electric scooters, generators - 6500 Watt. * Helmets * Great for Christmas Call now 519-357-4979 Continued on page 21 protek sandblasting & painting commercial • residential industrial Quality Workmanship You Can Trust Truck Painting Fleet Refinishing Equipment Refinishing Mobile & Shop Services www.proteksandblasting.comwww.proteksandblasting.comwww.proteksandblasting.com 519-523-9597519-523-9597 866-523-9597866-523-9597 519-523-9597 866-523-9597 Free Estimates Insured 519-523-4356 Complete Mechanical Service Computerized Tune-Ups Snow Tires - Mufflers - Brakes Vehicle Inspection Station 1997 FORD F150 4X4 4.6 litre, auto, off-road package $6,49 5 $4,49 5 1999 HONDA CIVIC 4 cyl., auto 2000 Ford Windstar -V6 auto, loaded 4 door 2000 Ford Escort -4 cyl., auto, 95,000 kms. 1999 Dodge Dakota -Ext. cab, 4x4, V6, auto 1998 Chrysler Concord -V6, auto, loaded, 145,000 kms. 1998 Dodge Neon -4 cyl, auto, 180,000 kms. 1998 Chev 1500 -5.0 L, auto 1997 VW Jetta -4 cyl., turbo diesel, A/C, 5 speed 1997 Buick LeSabre -V6, auto, loaded, 200,000 kms. 1996 Jeep Grand Cherokee -4.0L, auto, 4x4, loaded (519) 524-9878 After hours (519) 529-3339 Service all makes & models 2 Full-Time Licensed Mechanics Custom exhaust bending up to 3" pipe. Aluminized pipe. Walker mufflers Guaranteed for Life!