How Tires Affect Vehicle Road Test Results

You’ve probably seen published road test results from magazines—or seen and heard them as part of online video road tests—and wondered, “Hey, that’s nothing close to what my car does, and I have the same brand and model as the one in the test.”

Well, sort of. Is your car really the same as the vehicle being tested? Model and equipment packages vary so widely, and equipment changes so much from year to year, that the chances are slim that your ride is exactly like the vehicle tested, even if your car and the magazine’s test car look pretty much look the same.

Sometimes, you can be a bit disappointed when you get a vehicle that doesn’t deliver on the promise of the road test numbers. What can differ? Engines, for one. Some models offer everything from small, normally aspirated 4-cylinders to 6-cylinders and even brawny V8s. You better believe the acceleration and fuel mileage test results will vary by engine, especially when power-boosting turbochargers are added to the mix.

Other things can vary, too. Suspension calibrations, such as spring rates and shock damping, and the size of sway bars affect ride, handling and cornering capabilities. Different brake size, caliper styles and pad material can vastly produce different stopping distances and encourage or hinder brake fade. Transmissions—whether manual, automated manual with internal clutches, and traditional torque-converter-equipped automatics—can influence not only acceleration times, but also fuel economy, control and a vehicle’s personality.

Tires Affect Many Test Ratings

The one thing that perhaps influences more performance categories than any other—in fact, just about any performance category—is one of the vehicle’s cheapest components: tires. Think about it: Tires may make up a mere $400-$500 of many vehicles’ total cost and yet can completely change its personality. Even on a high-performance vehicle with tires that might cost $600 apiece, the rubber totals a small fraction of a vehicle’s bottom line. An engine option might cost $4,000 or more. A transmission option might cost $2,000.

Refer to the chart to see how tires influence road test results, and how different tires on an otherwise similar model will change your experience. Performance is likely to change if you buy the same model with different rubber, or switch later to a different style or size tire.

There are not good and bad tire characteristics as much a there are differing characteristics. Better handling is a good characteristic, but it often requires a wider tire that degrades ide quality and sounds louder. If you want a smoother ride and really don’t drive hard, a narrower tire that’s quieter and more comfortable makes total sense, even though many people would say it’s not “as good” a tire.

It all depends on how you drive you car. For example, if you have a Ford Mustang convertible or a Mazda Miata that’s a second car and has summer tires, and you never drive the car in winter, summer tires may be perfect. If you get deep snowfalls and have winter tires for four months a year, the summer tires for the rest of the year also make sense.

Change Tire Sizes, Types Safely

If you buy a car new and it comes with tires and wheels a different size than those on a vehicle described in a published road test, you’ll get different results but you’ll do it safely. That’s because everything is calibrated at the factory to the tire sizes and suspension components on the car. If you change tire type and size and the wheels yourself, however, you must make sure your new tire’s outer diameter is the same as the old tire’s diameter.