LAS VEGAS?You may know that there are specific tires for winter, for racing, for extreme off-roading ? but are there differences between one ?regular? tire and another? And, if so, does it matter when you?re buying new ones?
There are, and it can, because the appropriate tire for your vehicle and your driving needs ? as well as your wallet ? can improve your car?s performance and potentially keep you in one piece. Along with an attentive, well-trained driver, tires are your car?s most important safety feature. Everything else, from anti-lock brakes to airbags, is there to help pull you out of the fire once your tires lose their grip on the road.
I discovered this on some courses at the Las Vegas Motor Speedway, comparing Bridgestone tires to some of the competition. Two tires are new ? the updated Bridgestone Turanza Serenity Plus and Firestone Destination LE2 ? along with the existing Potenza RE970AS performance tire.
Tire manufacturers face a difficult task in balancing their products? attributes, since going too far in one direction results in a loss in another. With specialized tires, this is understood: an extremely grippy high-performance tire will wear out sooner. Mainstream tires have more all-around benefits, including wet-weather grip, long tread life, low noise, comfortable ride and low rolling resistance to help improve fuel economy.
In some cases, the differences between various brands can be minor. Although our testing was far from scientific, the Turanza performed similarly to the Michelin Primacy brought in for comparison. However, some can have far more noticeable variations. The Firestone outperformed its BF Goodrich competitor, sticking better in corners and on wet curves, as did the Potenza against its Michelin Pilot rival.
Several things differentiate tires, including the compound and tread. Each compound mixture ? a blend of rubber and various additives ? is a closely guarded secret. Winter-specific compounds stay pliable in cold weather, while summer tires remain firm in hot weather. ?All-season? tires use a compound that?s halfway between them, which is why driving pros recommend switching them for winter tires for maximum performance in cold weather. However, because they are ?stickier,? winter and summer tires also usually wear faster than all-seasons.
The tread pattern isn?t random. The grooves and blocks are meant to channel away water or slush, bite into snow, grip dry pavement, or crawl through mud, depending on how they?re designed ? whether to do one primarily, or in combinations. The pattern also helps determine how noisy the tire will be. The tread on all-season tires isn?t as aggressive as on winter tires, so while the winter tire is better equipped for snow and ice, it will generally be noisier on dry pavement.
Of course, the tire can only do its job when it has sufficient tread, and should be replaced when it?s worn. Tires have built-in wear bars, which are small rubber bars that run perpendicular to the tread. They?re difficult to see on a new tire, but if they?re visible and at the level of the tread, it?s definitely time for a change.
Tire sizes can be confusing if you?re not familiar with them. Oddly enough, the size includes imperial, metric and fractions. A P225/45R17 tire, for example, indicates that the tire?s width ? the tread area ? is 225 millimetres across. The 45 is the tire?s height, called the aspect ratio or profile, and indicates how tall the sidewall is. It?s the fraction: in this case, the sidewall height is 45 per cent of the 225-mm width, or about 101 millimetres tall. The ?R? indicates a radial-ply tire, and it fits on a 17-inch rim. The ?P? means passenger vehicle tire; you?ll also see LT, or light truck, on some heavier-duty tires for pickup trucks and large SUVs.
The tread width and sidewall height can determine handling and ride comfort. A low-profile tire ? one with a small sidewall, popular on large wheels ? will produce a firmer ride than a ?taller? tire with more sidewall. A tire retailer will usually suggest replacing tires with similar-sized ones, but if your vehicle has large alloy wheels, you may be able to go with a winter tire package that includes smaller steel wheels and a taller tire, which will have the same overall circumference but probably be far less expensive than fitting a large-diameter winter tire.
It?s unlikely you?ll get to test-drive different tires as I did, but a good tire retailer will recommend an appropriate choice based on your vehicle, how and where you drive and your budget. And no matter what tire you buy, check its pressure once a month. The correct inflation keeps you safe, reduces tire wear and helps save fuel ? and that all saves money.
Travel for freelance writer Jil McIntosh was provided by Bridgestone.