How Tire Tread Depth Can Affect Stopping Distance

January 7th, 2020 by

Close up of passenger side wheels on yellow Porsche 911

Porsche drivers know that keeping your tires in good condition is not only crucial to your vehicle’s ability to accelerate and maneuver on the streets of Milpitas, but it’s also important to your ability to stop. Ensuring you have the proper tire tread depth will help keep you enjoy the sporty nature of your Porsche while still staying safe in the Bay Area. Find out how tire tread depth is a contributing factor to your vehicle’s stopping distance, as well as how to calculate stopping distance yourself with this in-depth guide from Porsche Fremont’s tire center.

What is Tire Tread Depth?

So, now you know tire tread depth is important, but what is tire tread depth exactly? Tire tread depth is a vertical measurement between your tire’s deepest grooves to the top of the tread rubber. Since 1968, the recommended minimum tread depth for safe driving is 2/32 of an inch.

What is Reaction Distance?

Reaction distance refers to the distance traveled from the moment you recognize the need to stop to the moment you start braking. Typical driver reaction times range between 0.5 to 2 seconds, but reaction time can be altered by a number of factors, including:

  • Fatigue
  • Vehicle speed
  • Medications or alcohol
  • Anticipation of the need to stop

What is Braking Distance?

The distance traveled from the moment you apply the brakes to the moment your vehicle comes to a standstill in known as braking distance. This distance can be impacted by:

  • Vehicle speed
  • Your vehicle’s load
  • Tire tread depth and condition
  • Road conditions and gradient
  • Braking condition and technology

How to Calculate Stopping Distance

To get an accurate estimate of your vehicle’s stopping distance, both reaction distance and braking distance must be taken into account. Use the following calculation to help estimate your vehicle’s stopping distance:

  1. Start with the first digit of the speed your vehicle is traveling and square it. Add a zero to the result, and divide by 2.
  2. Now double your speed, and add that number to the previous result

For example, if your vehicle is traveling at 50 mph, you take the first digit, 5, and square it to equal 25. You would then add a zero to the end to get 250, which would then be divided by two to get 125. For your next step, you would double your speed of 50 mph (which makes 100 mph) and add that to your previous sum of 125. Once you complete all your calculations, you’re left with a stopping distance of 225 feet!

How Tire Tread Depth Impacts Stopping Distance

Tire treads are put in place to allow water, mud, debris, or snow to move through the grooves in the tire. Having treads allows more of the tire to stay in contact with the road during challenging conditions, thereby increasing your vehicle’s grip and control. While the current minimum recommendations sit at 2/32 of an inch, new studies are suggesting earlier tire replacements may be beneficial. TireRack conducted a study that showed that two sedans traveling 70 mph have significantly different stopping times when you let your tires get down to 2/32 of an inch. The sedan with 2/32 of an inch of tire tread depth took an additional 88.8 feet and 1.2 seconds longer to stop compared to the sedan with tire treads at 4/32 of an inch. With results like this, you may want to consider new tires sooner than typically recommended.

Find Tire Assistance at Porsche Fremont!

Aren’t sure where your tire treads stand? The experienced technicians at the Porsche Fremont tire center can examine your tires and make repair or maintenance recommendations as needed. In the event a full tire replacement is required, we carry N-Specific Porsche tires in the right size for the sports car performance and handling you’re looking for. Make your way to our tire center near San Jose and Hayward to have your tires checked and browse our tire inventory!

Posted in FAQ, Service, Service Tips