Many of the newer Executive Vehicles, including SUVs, come with Low Profile tires. There are advantages and disadvantages to low-profile tires.

Low-profile tires are all about the tire’s Aspect Ratio.

The Aspect Ratio of a tire is the ratio of the sidewall’s height to the tire’s cross-sectional width. If a tire has an aspect ratio of 60, the sidewall is 60% as high as the tire is wide. 

The lower the Aspect Ratio, the shorter the sidewall. Generally, low-profile tires have an aspect ratio of 55 or less, though this can vary slightly.

For example, the Mercedes Benz S550 Sedan has 255/45R/19 tires – The first number, 255, in a typical size, is the tire’s section width in millimeters, measured from sidewall to sidewall. If I want the tire width in inches, divide by 25.5. Hence the tires are 10 inches wide.

The tire’s aspect ratio or profile is the second number, followed by R. (255/45R/19). As we mentioned, this is the ratio of the sidewall’s section height to the tire’s section width. So the Aspect ratio is 45% – the sidewall is 45% as high as the tire is wide. 

You can calculate the sidewall’s section height by multiplying the section width by the aspect ratio percentage. For example, 255 mm x 0.45 = 115 mm or 4.5 Inches.

For example, the Lincoln Navigator Black Label comes with 285/45R/22 tires; when you work out the math, the bottom of the tire is 5 inches or 128.5 millimeters from the road surface.

The last example, a version of the suburban, has 275/50R/22 tires. When you work out the math, the bottom of the tire is 5.3 Inches or 137.5 millimeters from the road surface.

What are the advantages and disadvantages of low-profile tires?

The Advantages

• Improved handling
• Better braking
• Increased fuel efficiency
• Appearance – they look good.

Disadvantages

• A stiffer, bumpier ride 
• Rapid deflation: which may lead to damaging the wheels