Tyres: Standard v Optional

Automakers today give new-car buyers a choice of wheel and tire sizes, designs and applications. Unlike aftermarket wheels and tires, the ones offered by the original manufacturer are said to be safe and durable on the car in question — and they don’t breach the warranty. Even with their assurances, your choice affects the car’s safety, efficiency, comfort and damage resistance, so it’s good to know what you’re getting into. One model car may offer you more than one wheel size, while on other models, the wheel diameter automatically increases in higher trim levels. Whether they come with upgrades or as options, larger wheels will always you cost more. Automakers guarantee that the tires accompanying each of these wheel sizes have the same external diameter, measured from the tread, which keeps the speedometer correct and allows features like anti lock brakes and stability control to work correctly. So if the wheel’s diameter is larger, the tire has to compensate with shorter sidewalls. Why does this matter? Because shorter tire sidewalls will give you a firmer (read rougher) ride.

If you test-drive a car whose ride quality is borderline firm, take time to re-think before ordering a car with larger wheels if you haven’t experienced them out on the road. The same thought applies to run-flat tires, which are sometimes an option instead of having a spare tire. All other things being equal, run-flats usually ride more firmly than common tires.  Taller sidewalls don’t just protect you better from bumps in the road — they will certainly help to protect the wheels on which they ride. Hit a bad pothole with a large wheel and sporty low-profile tire, and the wheel is more likely to endure damage than would a smaller wheel. Further, if you drive up against a curb while parking, a smaller wheel will usually emerge with no more than a scuffed  sidewall.

A larger wheel, which is lower to the ground, might not survive such a close encounter. All-season tires are typically installed on most all cars; the exceptions are sports cars that aren’t meant for cold climates, some of which come only with summer performance tires.  Summer, winter and all-season tires are self-explanatory in terms of what they are intended for. What’s less obvious are the safety, efficiency and longevity issues. Though they maximize grip in warm, dry weather, the soft rubber compounds used in summer tires harden when the weather goes cold and become hazardous — and are even more so on snow or ice. Summer and winter tires aren’t your best choice if you’re a stickler for mileage — described either as fuel economy or how long they will last.  Summer and winter tires are less efficient. Likewise, they don’t last as long as all-season tires.

Even if summer or winter tires are a no-cost option when you purchase the car, they’re only truly no-cost if you live in an all-summer or all-winter climate. More often than not, owners with those tires really should switch them twice a year. In these cases there’s the added cost of a whole other set of four tires (different seasonal types cannot be mixed) plus the trouble and expense of re-mounting them twice a year. Even if you own both sets on their own wheels, mounting, balancing and storing a second set are additional expenses you’ll need to keep in mind. So, if you’re in doubt, we recommend sticking with the well known all-season tires. In addition to the longevity and efficiency advantages, all-seasons hold up well in all conditions, and the past few years, we’ve seen them creep even further into performance levels once known only to winter and summer tires.