You’ve spent untold amounts of time and money on your ride. You’ve squeezed every last horsepower from your engine, beefed up the gearing and suspension—even sprung for that custom paint job.

But what about your tires?

Tires are essential to the performance, handling, and safety of any vehicle—whether it’s a custom hot rod or a daily driver. Yesterday, we talked about choosing dirt bike tires. Today, we’ll show you how to find the right tires for your car or truck by following these five steps:

Identify the Need

The most important reason to buy a new set of tires is safety. Worn tires will cause loss of traction and reduced ability to stop, particularly in inclement weather. Inspect your tires for wear and follow these guidelines:

  • Tires are considered worn at 1/16-inch minimum tread depth
  • Tread depth of 1/8-inch or less means a significant loss of wet traction
  • Tread depth of 3/16-inch or less leads to traction loss in snowy conditions
  • Irregular wear necessitates early tire replacement

Replacing all four tires is the best case scenario; however, if you need one tire (due to damage, a defect, irregular wear, etc.), we recommend that you replace it with a tire that has a similar speed rating and load capacity to your three remaining tires. If you need two tires due to poor or irregular wear, replace the tire with ones of similar or better quality.

Another reason people upgrade their tires is to enhance the styling of their vehicle. There are a variety of distinctive tire styles to choose from, including:

Review the Ratings

A third reason people replace tires is to achieve better performance. Tires use a variety of tread designs, which incorporate tread blocks for traction, sipes and grooves for wet-weather handing, and tread shoulders for cornering ability. You can choose from many tread designs, but you should always follow the tire manufacturer’s speed ratings.

Generally speaking, the speed rating directly affects a tire’s handling response. For example, you will sacrifice handling and high-speed performance by choosing a tire with a lower speed rating than the OE tire. Conversely, you can improve your vehicle’s handling with a higher speed-rated tire, so many performance enthusiasts upgrade to higher speed-rated tires. Here is a list of speed ratings and corresponding speeds—remember these are test speeds, not recommended speeds:

Q-rated—up to 100 miles per hour

R-rated—up to 106 miles per hour

S-rated—up to 112 miles per hour

T-rated—up to 118 miles per hour

U-rated—up to 124 miles per hour

H-rated—up to 130 miles per hour

V-rated—up to 149 miles per hour

W-rated—up to 168 miles per hour

Y-rated—up to 186 miles per hour

Z-rated—149 miles per hour and over

Choose a Size

Most people replace old tires with the same size that was on the vehicle. There are various locations you can check to determine construction (radial or bias-ply) and tire size: tire sidewall, vehicle owner’s manual, and vehicle tire placard (this is usually located inside the glove box door, fuel door, doorpost, or door edge of your vehicle). Keep in mind, though, that you can often improve ride and performance by changing the size of your tires.

By changing to a lower-profile tire size, you can significantly improve the ride quality and handling of your vehicle. For example, by switching from a 155/80R-13 tire to a 175/70R-13 tire, you’ll get better handling and stability. That’s because the tread is almost an inch wider, and the tire has a proportionately lower side while maintaining the same tire height.

Another option is to plus-size your tires. A plus-size tire is the same height as the original, but its sidewalls are shorter. This change delivers improved tire response and handling and offers a desirable appearance, especially with larger rims. As a result, plus-sizing has become very popular.

A third way to improve performance is to upsize your tires. Upsizing, or selecting a larger tire, is a common choice for truck and SUV owners who like the traction, load carrying capacity, and appearance of taller, wider tires. Larger tires can also provide performance benefits for cars; however, you should follow these guidelines when upsizing:

  • Make sure the tire has load carrying capacity equal to or greater than what the vehicle placard suggests
  • Verify that the rim width range is appropriate for the tire to be installed
  • Confirm that the tire-to-vehicle clearance, lock-to-lock steering and suspension clearance is such that no rubbing occurs

Consider the Conditions

Driving conditions are a major factor in choosing the right tires. For example, a person who lives in the Northeast will often choose a different tire than someone living in Florida or California because of varying weather conditions. Off-road enthusiasts will pick a different tread and tire size than someone who sticks to the street.

For seasonal extremes—snowy winters to summer droughts—consider all-season tires. These tires are ideal for drivers who need good performance and traction for all possible driving conditions throughout the year. All-season tires are a convenient, affordable alternative to swapping out seasonal tires.

Choose seasonal tires for superior performance and traction during a particular season or climate. Seasonal tires provide better performance and traction over all-season tires, which are not purpose-made for any specific driving condition. In non-snowy climates, for example, summer or dry type designs are emerging as year-round favorites. These designs feature far superior dry handling and traction with wet performance ranging from acceptable to excellent. Performance enthusiasts who live in more extreme winter climates also use these new designs when seasons allow and change over to winter tires once the snow begins to fall.

Make sure you also consider terrain when choosing tire design. This is especially important if you drive a pickup or SUV that sees off-road duty. In terms of traction, designs range from HT (highway tread) to AP (all-purpose) to AT (all-terrain) to MT (mud terrain) in order of aggressive tread design. You can pick tread aggressiveness according to your needs, but be mindful of the highway ride quality tradeoff. Highway ride quality diminishes as the tread design becomes more aggressive so make an honest assessment of your driving habits to strike the right balance.

Know Your Rubber/Don’t Skimp

1966 dodge charger magnum wheel
(Image/OnAllCylinders – Patrick Miller)

As with anything, you get what you pay for when it comes to tires. You can calculate tire value by taking the total price of the tires and dividing by the miles of service (based on mileage guarantees). This will give you a cost-per-mile value for each tire. You can also comparison shop by using tread wear, traction, and temperature ratings.

Each year, tire manufacturers are developing new specialized designs for the wide array of vehicles on the road. You can choose anything from long-lasting tires radials to style-conscious, ultra-high performance tires–the choices are seemingly endless!

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Author: David Fuller

David Fuller is OnAllCylinders' managing editor. During his 20-year career in the auto industry, he has covered a variety of races, shows, and industry events and has authored articles for multiple magazines. He has also partnered with mainstream and trade publications on a wide range of editorial projects. In 2012, he helped establish OnAllCylinders, where he enjoys covering all facets of hot rodding and racing.