Spin Control: Smart All-Wheel-Drive Is Your Friend

Jim Motavalli

Jim Motavalli | Feb 03, 2017

LIME ROCK PARK—It gets cold in northern Connecticut in February, but even so Buick had to make some snow for our winter driving event at this fabled race track. And then it started snowing while we were driving.

The AWD Buick LaCrosse tackles the hillclimb. All-wheel drive isn't just for SUVs these days. (Jim Motavalli photo)

Winter driving remains a challenge. Some 41 percent of weather-related crashes in the U.S. are related to snow and ice. At least until we’re all in self-driving cars, we’ll endure 150,000 winter-related traffic injuries, and 2,000 deaths, annually, the Federal Highway Administration reports.

The cars were Buick Envisions and a LaCrosse, and the point was to emphasize the importance of stability control in keeping your car on the road when the weather turns bad. Premium trim Envisions get a twin-clutch all-wheel-drive system. According to Buick’s Mike Ofiara, the system “monitors the driver’s intent to provide maximum performance.” That’s great, because I don’t always know my own intent.

Testing traction in the twin-clutch Envision. (Jim Motavalli photo)

In real terms, this means the hydraulically controlled system (BKN developed it originally for the LaCrosse), replacing a traditional differential and single clutch), can send 100 percent of torque to the front wheels, to the back wheels, or a “dynamic” blend of something in between. In snow, the rear wheels get power. The system makes pre-emptive decisions based on how much throttle you give the car.

Carmakers have done great work lately with all-wheel drive. Hybrids can create it by having the front wheels driven by the gas engine, and the rear with electric (or vice versa). And then you can manage the two axles for maximum traction. Battery cars can simply have two electric motors, with great low-down, stump-pulling torque for winter.

Tight parallel parking between two snowbanks in an Encore. (Jim Motavalli photo)

On the track, the twin-clutch system was great fun. We were free to drive like idiots—flooring it on the snowy straightaway. There was some tail wiggle, but the Envision absolutely refused to get in serious trouble, cutting power right down and distributing the torque that was left to the corner that needed it.

On a hill-climb test, the Envision spun a bit but then hunkered down, delivered power, and shot forward. A front-wheel-drive Lexus ES350 brought for comparison was much slower off the line. Similarly, an Acura MDX with the SH-AWD system lost a traction test with the Envision.

Heading out for some heavy-duty winter action. (Jim Motavalli photo)

It’s worth making the distinction here between all-wheel and four-wheel drive because they’re not created equal. The latter is what you find in trucks (especially older ones), and it just means that (when it’s turned on--some systems need to be engaged) power goes continuously to all wheels all of the time. AWD is much better, especially in winter. It’s on all the time, and it varies power to the front and rear wheels as necessary. If there’s a loss of traction, then all four wheels get power.

I don’t need to be convinced of the value of traction control. Here’s Consumer Reports’ take on what it does: “Traction control helps maximize grip by limiting how much the drive wheels can slip. It does that by rapidly and strategically applying the brake of a slipping wheel, which shifts traction to the opposite one, and sometimes by cutting engine power or upshifting the transmission to minimize wheel spin.”

Traction control isn’t just for winter. Doug Osterhoff, marketing manager for the Buick LaCrosse, says the twin-clutch system “has a real performance element to it, with big benefits on acceleration and cornering. We think this will have more play.” Buick is using its twin-clutch system to gain some product differentiation in a market that’s now really crowded with AWD SUVs.

Deep thoughts: Is this coffee cup too short, or is the Envision cupholder too deep? (Jim Motavalli photo)

Traction control used to be seen as a luxury, and an expensive option to check. Often, it was available only as part of costly packages. My wife and I just bought a 2009 Honda Fit, and it’s the top-of-the-line model with a rather primitive (DVD-based) navigation system. The benefit, aside from a stereo upgrade, is that it’s the only Fit equipped with Honda’s Vehicle Stability Assist system. Since we’ve been Fit owners since 2007, we’ll get to see how much better the system handles the snow.

It’s good to report that electronic stability control (ESC) has been mandated on all passenger vehicles under 10,000 pounds since 2012. That’s saved a lot of lives. Here’s the federal safety agency on the subject: “ESC has been found to be highly effective in preventing single-vehicle loss-of-control, run-off-the road crashes, of which a significant portion are rollover crashes. ESC has also been found to reduce some multi-vehicle crashes.”

Tires are also important: As I’ve written, all-season radials seem like the answer for people who hate swapping tires, but they’re ideal neither in winter or summer. I’ve just gone to the trouble of acquiring winter tires for my Mazda Miata and mounting them on the car’s original wheels. Of course, it would matter more if I actually drove this garage queen in snow.

The bottom line is you shouldn’t get smug just because you have an SUV driven by all four wheels. You still have to drive super-carefully, consider winter tires, and be knowledgeable of what happens to a heavy car in snow or on ice. And assuming your car is post-2012, rest assured that the ESC will be your friend when the weather turns inclement.  


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