Winding Road's Guide To Winter Driving
By Winding Road Staff
February 19, 1999
Despite the April Issue indication you may have noticed on the cover of this month’s Winding Road (check out our full new issue at www.magazine.WindingRoad.com), it’s actually just around the middle of the long Michigan winter as we write this. That’s bad news for anyone who values anything in the way of a short sleeve or a naturally occurring tan, but it’s surprisingly good news for us driving enthusiasts.
We lean towards that group of people that embrace four full seasons in all of their glory, and love to drive through each of them. Which is why we’ve been paying special attention this year to the motive joys that can be had when our world is white. Be it driving a sports car or a convertible, with a new set of snows or in a frigid testing environment, we’re into winter driving. Find out why.
Winter Driving: The Camaro SS Test
By Steven J. Ewing
For those of us who live in the Snow Belt, performance cars aren’t necessarily the best choices for daily drivers. When snow and ice cover the road, front- and all-wheel drive are best suited for managing the slushy stuff, but even rear-drive cars aren’t too bad most of the time, especially when your car is outfitted with proper winter tires. Having the right rubber can really make a huge difference, and our staff had the chance to experience this first-hand recently. And no, we aren’t talking about fun drifting exercises in all-wheel-drive sports cars, though as we found out around this time last year [LINK], that proves to be an immensely fun way to spend a winter day, too.
On a cold Tuesday morning in early January, a black Chevrolet Camaro SS arrived at our door. We were initially worried about being able to navigate the 6.2-liter V-8-powered beast through the winter weather, especially since a big storm was in the forecast—potentially dumping up to six inches of snow in the metropolitan Detroit area. Our General Motors test car representative reassured us that the Camaro would be wearing snow tires—Pirelli Scorpion Ice & Snow, to be exact—and that we shouldn’t have too many issues. What’s more, our test car was optioned with the six-speed manual transmission, which would allow us to select higher gears at slower speeds, which is a good thing to have when it’s hard to gain traction on some surfaces. Even so, our Camaro, with its RS appearance package, would be wearing twenty-inch wheels, best suited to be wrapped in wide, performance rubber. For warm, dry conditions, low-profile, wide tires are what you want on a Camaro, but in the winter, it’s just the opposite. In fact, well-known tire resource, The Tire Rack suggests that consumers move down one tire size when buying snow tires, since smaller-diameter, thinner wheels really are better suited for traction in the snow and ice.
During the course of our time with the Camaro, we found that the tricky part wasn’t necessarily keeping it in a straight line, but managing the power delivery. Starting in second gear is an easy way to not spin your rear tires off the line, and while shifting at 3000 rpm isn’t the most exciting way to drive a Camaro SS, it certainly means your back end won’t get all fidgety during the drive.
Another key thing to point out about sports cars in the winter months is that ground clearance makes all the difference. Your author happens to have an unplowed, unpaved, gravel and grass driveway, and the Camaro never once hesitated to move from its parked position. For reference, we tested a Jaguar XF with all-season tires in similar conditions two years ago, and it had to be towed out of that very same driveway. If that isn’t a testament to snow tires, we don’t know what is.
As an exercise in what is possible then, our snows-equipped sports car proved to be completely capable by then end of our week with it. But the story doesn’t end there, completely. Sure, there are ways to avoid the natural disadvantages of driving high-powered, rear-wheel-drive cars in winter weather, but the fact remains that most of the joy of driving those cars is stripped away in the process. After all, the Camaro is supposed to be a truly joyful machine, with a lot of its value coming from the entertainment it is able to deliver. Just because it can get by in the snow, doesn’t mean it’s any fun to drive in it, which means that snow-state driving enthusiasts might want to consider other solutions.
Although a Camaro may not be your (or our) first choice for a four-season sports car, know that with the right tires, decent ground clearance, and proper driving techniques, it’s possible to weather the storm with grace and ease. You just might need to find your weekend thrills somewhere else.
Winter Driving: Convertibles In The Cold
By Seyth Miersma
The wind passing gently across your exposed, proffered cheek, a lively exhaust note ringing, unfiltered in your ear, and a bevy of envious glances from motorists at every stoplight—ah, the joys of open top motoring. We’re firmly on record as being huge convertible geeks here at Winding Road, which is why we just couldn’t resist adding a piece on drop-top driving to our winter segment this month.
Let’s face it, for those that happen to live in areas of the world blessed with snowy winters, the traditional convertible-driving season is pitifully short. And despite massive improvements in the way of all-weather comfort, even for convertibles, too many otherwise intrepid enthusiast drivers either leave the ‘vert in the garage for the wintertime, or worse, drive it top-up. The truth of the matter is that there is a lot of fun to be had with the top down in the winter, as long as you keep a few key points in mind.
Technology Is Your Friend
Just like you most of you out there, we’ve got a few memories of some really, really cold rides in older convertibles. (Your author spent his formative years riding or driving in a few Volkswagen Rabbit cabriolets that were always topless—because they were broken.) Time was when soft-tops were drafty, leaky, and/or cold all of the time. But times have changed. In addition to having better and more weatherproof soft- and hardtops for when there is actual precipitation, today’s convertibles offer the kind of amenities that keep you cozy when the world is chilled. Heated seats are a real blessing for any car during cold weather, but they’re a total delight for winter convertible driving. These bum warmers do a great job keeping your core body temperature up, while the cold air swirls around your head—we compare this to the pleasure of sitting in a hot tub at the ski lodge.
In addition to simply having better heaters than in generations past, convertible makers are also doing great things with directed warmth, as well as deflecting the wind. Mercedes-Benz, in particular, with its really effective Airscarf system, uses a vent in the car’s headrest to keep one’s neck and face from getting overly frosted. Mercedes is also making important strides with its new E-Class convertible, which uses active aerodynamics on the top of the windscreen to deflect rushing air over (rather than at) the heads of all four passengers. A good trick for decibel levels, as well as overall warmth.
Dress For The Cold
Our mothers always yelled at us to bundle up when we were headed out to play in the snow—advice that will help a ton if and when you decide to start rocking your convertible in the winter. You have the maturity and financial wherewithal to own a fancy convertible car, we’re sure you can afford to buy a hat, scarf, and gloves.
Yes, yes, we just got done telling you how snug and cozy a space the new convertible can be. But that doesn’t mean a few bucks worth of cold weather gear isn’t in order. Mercedes may be doing fine things with active aero, but most ‘verts will still require you to cover your head if you want to stay toasty. A warm cap or a beanie serves well here.
Gloves are a close number two in rank of importance, after hats, as even high-end cars equipped with steering wheel heaters can leave a bare hand a bit chapped. Stick with a glove that’s thin, nothing too bulky, as you’ll want to keep as much tactility as possible. A turned up collar can work as well as a scarf in most instances, but you’ll miss out on some of the cool, wind-blown look, for sure.
As for the rest of your outerwear, remember that most of your body is going to be bathed in the warm heat of a powerful, modern HVAC system, and don’t go too heavy on the coat. Layers (a sport coat or jacket over a fleece works well) are a great way of providing plenty of mobility, without getting yourself overheated.
Lastly, don’t forget your sunglasses. Even if it’s not overly bright out, you’ll likely want an eye barrier against that chilly breeze (and you’ll look like a badass).
Aim For The Back Roads
Even if it’s relatively easy to beat the cold, there are still fewer dry and inviting days to going driving in the winter than there are most summers—don’t waste your opportunities with mundane highway driving.
When running over mile after mile of your favorite undulating and challenging road, the bracing winter air has a way of really accentuating the experience. That crisp vibe can get ruined pretty easily on the freeway, however, where high speeds and straight roads lead to colder, duller driving than anywhere else. Even the best cold weather convertible will be overcome by 80-mile-per-hour winds for dozens of miles at a time. Shorter, more interesting drive routes will not only slow (most of the time) your average rate of speed, but they’ll also keep your mind firmly focused on the challenge at hand.
Don’t Forget To Wave
We won’t lie to you, if you drive your convertible top-down in the wintertime, you will be stared at.
We recently spent a weekend doggedly driving al fresco behind the wheel of a Nissan 370Z Roadster—the temperature gauge never showing higher than 27 degrees—doing plenty of around-town errand running between shots through the country. Clearly, the new Z is on the flashy side, even as convertibles go, but the average reaction to our top-down driving went far beyond the Nissan’s cool factor. People went crazy.
We were yelled at, honked at, or given a slew of friendly thumbs up almost everywhere we went. One older gentleman in a Lincoln mouthed at us to, “get inside” with a sort of a scowl on his face (true story). Two young women in a Saturn Sky (top up) gave us a spring-break-worthy “hell yeah!” that was equally undeserved, though considerably more pleasant than the cranky old dude’s warning. Depending on how shy you are, this level of outsider involvement in your drive may be a good thing or a bad thing—fair warning.
It’s time for the hearty-soup-and-snow-boot belt of America to start enjoying the sort of year ‘round driving joy that those pesky warm weather states have had for ages. Give it a shot, take your top down.
Winter Driving: Snow Tires And The Performance Driver
By Rex Roy
Back in the mid-1970s, Chicken Little know-it-alls clucked about Global Cooling (see Newsweek April 28, 1975). Having gotten used to winters that reflected two decades of cooling, drivers in the Midwest fretted not, and responded to the weather by seasonally fitting dedicated snow tires to the drive axle of their domestically-produced, rear-wheel-drive cars.
As a teen learning to drive in Detroit during the 70s, driving through snow was just something everybody did. Learning from my father that my hand-me-down 1973 Charger was a veritable dog on ice when the snow fell (imagine the dynamics of 68/32-percent weight distribution and wide bias ply tires), your author fitted the big-block Mopar with studded snow tires from Thanksgiving to Tax Day. Evidence of the 440 Magnum V-8's power and the grip of the Uniroyal snow tires can still be seen in the scarred concrete in front of my boyhood home.
While temperatures have continued to swing, snow tires continue to be an important component of safe winter driving even with the proliferation of all-wheel-drive cars, crossovers, SUVs and trucks.
The Cold, Hard Facts
Falling temperatures change the performance characteristics of tires. The magic number according to most tire manufacturers is 45°F (7°C for our valued Canadian readers). It is at that point when the rubber treads on all-season tires begins to harden. The stiffening tread blocks reduce tire grip.
The effect is most dramatic driving a car shod with summer-only high-performance tires. The tires figuratively “freeze” and offer the grip of plastic furniture glides when the mercury drops. Given this reality, modern snow tires should always be fitted in full sets, not just to the driving wheels.
The Winding Road staff experienced an extreme example of this last winter when Mitsubishi blessed our fleet with an Evo X in January. Frigid temperatures rendered the sophisticated all-wheel-drive sports car completely impotent and wholly unsafe to drive even on dry pavement. It remained parked for much of stay solely because of the tires. The characteristics that provide distinct benefits in the cold weather make dedicated snow tires act like Frosty The Snowman when temperatures rise. As temps climb above 50°F, snow tire performance melts away. Handling characteristics tend toward feeling greasy or loose. Narrow environmental performance windows support consideration of two sets of tires for many drivers.
What Makes Snow Tires Snow Tires
Advancing with general-use and high-performance tires, modern snow tires are much more sophisticated than in decades past. Literally hundreds of sizes are available to fit nearly every car driving near or above the 45th Parallel. The latest iterations sport speed-rated, asymmetric, directional tread patterns with multiple dedicated features designed to provide improved traction, grip, and braking performance on snow and ice.
Snow tire technology begins with softer, silica-rich compounds that remain pliable in cold weather. Special siping (tiny, engineered cuts in the tread blocks) further enhances grip on ice, while wide longitudinal grooves help channel water and slush away from tread blocks in an effort to help the tire slice through to the hard pavement. Recognizing that snow tires aren't always traversing the white stuff, big tread blocks on the outside edge of high-performance directional snow tires provide excellent dry-surface grip.
In lousy, cold driving conditions, the extra traction (estimated at 25 to 50 percent) provided by snow tires can generally shave 10 to 25 percent off of braking distances compared to all-season tires. At higher speeds, the added braking performance adds up to multiple car lengths, often the difference between making it home in time for dinner or a flat-bed ride to a collision shop.
Making The Choice
With many drivers keeping cars longer, tire manufacturers are quick to point out that most owners will purchase at least one set of replacement tires. Their suggestion to drivers living in colder climates is to purchase a set of snow tires before their first winter, which could double the life of their original tires in a move that wouldn't necessarily add extra cost over the life of the car.
It's not bad logic.
Beyond the brand and model of tire you'll need to select, another choice is whether to purchase new wheels along with the new snow tires. Two advantages to an extra set of rims are extending the cosmetic life of your vehicle's OEM wheels, and providing the option of changing the diameter size of the snow tires you choose.
While it is not possible for all vehicles, going to a smaller diameter wheel while increasing the aspect ratio of the tires offers traction advantages in snow (because of specially designed tire shoulders) and improvements in ride comfort. For example, the Camaro we recently sampled could have just as easily been fitted with P245/55R18 snow tires as opposed to the P245/45ZR20 Pirelli Scorpions it arrived on. The dedicated snows could have been mounted on inexpensive aftermarket wheels or even stock eighteen-inch Camaro steel wheels.
To help you with your decision-making, the following is a quick look at some of the most popular snow tires available.
Most of the world's highest performance cars ride on some version of Michelin Pilot Sport tires. This is no mistake. Bibendum ain't full of hot air (we think it might be marshmallow).
Technology gained in developing supercar tires has migrated to dedicated snow tires, including the Pilot PA3 (recommended for the Porsche Panamera), Primacy Alpin PA3, and X-Ice Xi2. A unique Helio compound in the PA3 tires incorporates hydrophilic sunflower oil that literally helps the tire grab hold to snow, slush and water to maximize bad-weather performance. The X-Ice tires are more general purpose, targeting regular passenger cars and minivans.
Pirelli continues to expand its line of Scorpion tires. The famous-for-our-calendar tire company introduced the Scorpion Ice & Snow as a high-performance offering directed at modern muscle cars, and luxury crossovers and SUVs.
At the Tire Rack, owners rated the Pirelli highest in the category and gave it a "superior" rating. The line of tires is also aggressively priced.
Bridgestone's game-changing Blizzak winter tire (introduced in 1988 and revised multiple times since) employs what the manufacturer calls a Multicell rubber compound throughout the top layer of the tire's tread. The microscopic cells resemble Swiss cheese, and have the impressive ability to improve grip on even the slipperiest road surfaces.
Having owned multiple sets of Blizzaks, your author knows first-hand how these tires can dramatically improve a vehicle's winter driving capabilities. Sizes are available to fit over 200 different vehicles. While solid performers, Blizzaks aren't the least expensive snow tire available.
The new series of snow tires just introduced by Continental is called ExtremeWinterContact (don't complain to the editor, there are no spaces). The new Contis feature a stepped tread shoulder that adds bite in deeper snow, as well as a high density of sipes. The EWC is offered in sizes ranging from thirteen- to seventeen-inch diameters and includes sizes for light trucks and SUVs.
It figures that the Finns would know something about snow tires. Nokian tires produces the Hakkapeliitta (sounds like of like "have-a-fajita"), a long-life snow tire that delivers performance developed by decades of testing 120 miles North of the Artic Circle. The uni-directional arrowhead arrangement of the treadblocks is a Hakkapeliitta trademark.
Winter Driving: The Land Where SH-AWD Was Born
By Tom Martin
If you live north of the Mason-Dixon line, or anywhere that it snows regularly, Acura wants to be your car company. While Acura’s SH-AWD (Super-Handling All-Wheel Drive) has been around since 2005, we don’t normally think of Acura as a brand for the snow belt crowd in the same way we do with Audi or Subaru. Even BMW’s xDrive feels like it has more mind share for the snow rallyist in each of us. So, ever curious about how brands are repositioning themselves, we recently travelled to Acura’s winter test facility in the very northern reaches of Minnesota to gauge Acura’s progress.
Back in the early ‘90s, Honda R&D Americas (the Ohio-based entity responsible, among other things, for the engineering of most Acuras) began a partnership with a new company called Automotive Enviro Testing. The facility that has grown out of this partnership is seriously impressive. AET covers 820 acres with nineteen different test tracks, including several autocross courses, split ice/asphalt hills of various grades, slush pits, cold chambers, ice and snow skid pads, and a 75-acre groomed “snowfield” for assessing high-speed vehicle dynamics. Other companies have similar test facilities, though, so what really matters is what comes out of the engineering that is tested at AET.
At AET we had a chance to sample a variety of Acura SH-AWD systems on many of the snow and ice tracks. We were able to run the Acuras side-by-side with some of the aforementioned competitors’ cars to see where the chinks in the AWD armor are. And chinks there are. In fact, after a day of blasting across the super carefully prepared tundra, we’d say the handling differences in snowy conditions between AWD cars are vastly more pronounced than the difference in the dry.
Let’s start with something simple. In basic winter driving around town you often face the problem of stopping at a traffic light on a hill. Previous cars will have polished some snowy areas into smooth ice, while other areas will have been ground down to the underlying asphalt. To test against this scenario, Acura uses what is called a “split-mu” (mu indicating the coefficient of friction) surface, where a strip of ice is laid down on the left side of the car and dry asphalt is on the right side. On a 30 percent grade (which is pretty steep—think Pittsburgh), we could easily climb the split-mu hill in the Acura MDX from a dead stop, but couldn’t really move the Audi Q7 or the Lexus RX350 forward more than a few feet before wheel spin on the icy side stopped the fun.
The explanation for this is rather straightforward. In this case, the car needs to deliver torque to the dry side tires (right side in this example). Audi and Lexus can adjust relative torque delivery side to side, but they do this by applying the brakes to the slipping wheels to slow them to the rate of the wheels with traction. Since the wheels with traction basically aren’t moving, the car simply won’t move as the traction control intervenes via braking action. Acura, by contrast, has a rear limited-slip locking differential, so they can send more torque to dry wheels (rather than less to the slipping wheels). The result is acceleration because the dry side wheels get enough power.
Another, and we’d say more critical, example comes across in the lane change maneuver. Say you’re driving down a two-lane highway on a snowy night. Visibility isn’t perfect, so you suddenly encounter a deer standing in your lane (we’ve had this happen, only with an Elk rather than a deer). Naturally, you swerve left to avoid inviting the deer to join you in the front seat. But can the car respond?
We tried a version of this with an Acura ZDX, a BMW X6, and an Infiniti FX35 (no deer were abused or even involved in our testing). To perform well, the car has to initiate a left turn quickly, avoid spinning as a result of the turn, and then repeat this back to the right (or you end up in a ditch or wrapped around a tree on the opposite side of the road). At 50 miles per hour, the ZDX turns crisply and transitions nicely back the other way. Not hugely different from the general kind of dynamics you’d expect on a dry surface, though more slippage is evident (snow has about one-third the friction level of asphalt). The car more or less goes where you point it.
The BMW and the Infiniti are a study in contrast, both with the Acura and with each other. The X6 feels very controlled on the snow. But when you swerve to avoid the hypothetical deer, you don’t get all the way into the other lane. We’d say you clip the deer with the right front fender or smash the mirror into the deer’s head. That’s because the X6 wants to understeer a bit to retain stability. The Infiniti is just the opposite. The FX35 is simply too eager to rotate, and the tail wants to whack the deer before you slide sideways into the opposite ditch.
With more experience in each of these cars, you might be more aware of their dynamic tendencies. Still, we’d say the dynamic headroom of the Acura exceeds the other cars we tried. And we’d point out that emergency work on snow often isn’t something you’ve practiced, so the extra headroom seems especially valuable in this kind of scenario.
At this point some of you may be thinking “Safety, schmafety! Are these cars fun to drive in the snow?” We could just say “hell, yeah!” and leave it at that, but there’s more to the story.
If someone should randomly offer you the chance to do a bunch of hot laps on a snow covered race course, do not hesitate, do not pass go, just say yes. The ability to run at the limit with a great sense of impunity (because the speeds are about one-third as high and the guardrails are made of fluffy stuff, not Armco) is freeing. The learning experience is also tremendous because your bad habits are punished severely—after getting the entrance to a corner wrong the recovery seems to take an eternity.
To make Acuras enjoyable in winter conditions, Acura’s all-American engineers have spent a ton of time building an AWD system that does three core things. First, they’ve created a traction/stability system that raises the dynamic capability of the car. In simple terms, if you (a) create a mechanically balanced chassis, (b) can brake each wheel independently, (c) can send torque to each wheel independently, and (d) can adjust these actions at light speed, you should be able to keep the car stable at higher speeds than Fernando Alonso without traction and stability control (because even Alonso can’t brake or power each wheel independently). Acura hasn’t quite done all that, but it has moved in that direction.
Second, it’s honed the software to make the reactions of the car feel predictable. We went into this test with the feeling that many drivers overestimate what their cars can do on snow. We came out of it with the feeling that the car can do a lot more than you’d think, but you have to sense in your gut that you can ask more. Building systems that inspire reasonable confidence is key, and Acura (along with BMW and Audi) have got that.
Third, the Acura boys have created a traction and stability system that feels un-intrusive. A lot of these systems intervene in a way that kills the fun, hence the pejorative term “electronic nannies.” But Acura’s approach is much more like “electronic rally instructor,” because the system works overtime to avoid retarding forward momentum (see chart) and to smooth out lateral transitions (Acura’s magneto-rheological dampers’ high speed adjustment capability is brought to bear here).
We took an SH-AWD Acura TL with manual transmission out to one of the “autocross” courses (really a roughly one-mile road course paved with groomed snow) at AET. We blasted around for lap after lap of power slides in the TL and a BMW 335i with xDrive.
The TL is near maximum fun in these conditions. The SH-AWD can really put the power down, and the manual transmission gives a great sense of throttle linearity and control. SH-AWD also does a nice job of allowing plenty of slip angle while generally keeping the TL pointed in the right direction.
When we ran the 335i on the same course, with DCT partially engaged (full-on is a fun killer), we definitely ran great average slip angles per lap. The BMW system in this mode isn’t terribly intrusive, but it also can’t do as much as the Acura system to keep you on line.
That said, the 335i was in some ways more fun. Lurid slip angles warm the heart, sure, but the 335i also feels a little more natural to us. You know you’re on snow, and you’d maybe like to dive into a corner, power the tail around, and blast down the next straight. This seems more the BMW’s oeuvre than the Acura’s. Such driving is aided by the fact that the BMW’s steering feel is a world apart from the TL’s.
The TL is a little more like driving a video game. You quickly learn, for example, that steering angle controls the throttle/brake as much as your foot. That’s because the more steering angle you crank in, the more stability control has to slow the car to get within the limits needed for that radius of turn (tighter radius = slower). The cool thing is that the Acura system is so fluid that you can do this stuff enjoyably. The feel is just less traditional.
So, does Acura have a worthy competitor to the established AWD brands? More than worthy we’d say. In most ways, the SH-AWD system is state-of-the-art on snow. Given that the underlying cars (especially the TL) are pretty competitive, we have the feeling there’s a new player in [insert snowy town name here]. If Acura (or Audi, or Subaru for that matter) can apply the same effort to steering that they’ve applied to AWD, BMW had better watch its back.