Winter driving: FWD vs. AWD
All-wheel drive is best, but better tread also makes a big difference


Go-anywhere grip is a major part of the popularity of sport-utility vehicles. Automakers are capitalizing on that passion for all-wheel drive by offering it on a growing number of sedans, wagons, and minivans. More than 20 non-SUV models now offer such systems, which provide power to all four wheels as needed.

Many all-wheel-drive vehicles are based on front-drive cars, which, in turn, tend to do better in snow than rear-drive cars because the weight of the engine and transmission sits directly over their drive wheels. Front-drive models cost about $3,000 less, on average, than all-wheel-drive models, weigh less, and use less fuel. And as with other vehicles, you can improve their snow traction with winter tires, which use special compounds and an aggressive tread.

How much difference can winter tires make? We compared four of our test cars: the all-wheel-drive Volkswagen Passat GLX 4Motion and its front-wheel-drive sibling, the Passat GLS, and the all-wheel-drive Volvo Cross Country and similar front-drive Volvo S60.

The tests. We gauged traction by measuring the distance it took to accelerate from 5 mph to 20 mph over packed snow. Because cold-weather stops can be especially challenging, we also tested braking from 10 mph over smooth ice. We drove the all-wheel-drive cars with their factory-issue all-season tires, which should get these vehicles through most conditions. Front-drive models were tested two ways--with standard all-season tires and with winter tires. Our results:

• The best were the all-wheel-drive cars, which reached almost 20 mph sooner, on average, than the front-drive cars equipped with winter tires.

• Winter tires yielded the biggest snow-traction gain for the buck, however. Using them helped the front-drive cars reach 20 mph nearly 28 feet sooner than they did with all-season tires. Cost: about $400 for four winter tires plus another $200 or so for an extra set of wheel rims to ease the switch to winter tires.

• Better traction won't guarantee shorter stops. Braking distances on ice were about the same for the all-wheel- and front-wheel-drive cars. But the antilock braking systems helped significantly; both Volvos stopped some 14 feet sooner with ABS than they did when we turned it off.

Our advice. Consider an all-wheel-drive vehicle if you live in a snowy area or want added peace of mind. For maximum traction, equip it with winter tires. In less-snowy areas, front-wheel drive and a set of winter tires should suffice. Mount winter tires on all four wheels for balanced handling. Remove them after winter, since these tires wear quickly on dry roads (plan on about three winters of use). And be sure to opt for ABS on any vehicle.