![]() ![]() Mazda calls this golden moment the “control area” (illustration above) where the car can intervene. This works at low speeds only and is not for highway driving.Īccording to Dave Coleman, Mazda development engineer, in bad weather there’s a time of limited traction where the tires are just beginning to slip that can be noticed by the car’s sensors (but not yet by the driver), and acted upon, so that power quickly begins flowing to all wheels. Some allow the differentials to be locked so the wheels turn at the same speed. Some are part-time 4WD, where the driver selects when to engage the system and then chooses a low or high gear range. ![]() A 4WD vehicle has a transfer case splitting off from the driveshaft to send power back to the front wheels, and differentials front and rear. Go to YouTube and you’ll see Subarus beating up on the competition in rollers-on-ramps tests where three of four wheels are slipping, an extreme but not rare event.įour-wheel-drive, or 4WD, vehicles are typically trucks and big SUVs with big, heavy drivetrains. Still, Subaru has been considered the champ of winter driving among under $50,000 vehicles. You don’t want heavy parts of the car at the far ends of the vehicle. At least theoretically, a drivetrain with powertrain always working both front and rear is harder on fuel economy, and the engine and transmission packaging may push the engine farther forward relative to the front axle. A center differential allows front and rear wheels to turn at different speeds. It’s always delivering torque front and rear, more or less equally split, and can deliver the majority of torque to whichever end has better grip. Here’s what I found.Īmong mid-priced cars, Subaru’s Symmetrical All-Wheel-Drive (drivetrain image above) is an exception to the part-time AWD design philosophy. Among affordable compact SUVs, Mazda crossovers with i-Activ AWD show themselves to be on equal footing with Subaru and better in some cases. The difference between all-season and winter tires is a huge part of the difference. Most every all-wheel-drive vehicle should get you where you’re going in most bad conditions. Now comes Mazda with its i-Activ system that attempts to leapfrog the competition by predictively shifting to AWD, before you start to slip, based on inputs from more than two dozen sensors.īased on testing I did at multiple snowy and icy sites in the US and Canada this winter and in the past, it’s clear that good all-wheel-drive and winter tires make a significant difference. ![]() For years, Subaru’s Symmetrical All-Wheel-Drive has been highly regarded. Now that AWD is on one in five cars and crossovers sold, automakers are trying to show how their version is better. “And it has all-wheel-drive.” That’s a strong selling point most any time of year, and only more so in snow season. ![]()
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