What's in a Number? (What Tire Numbers Mean)

Posted November 28, 2021 8:12 AM

You've probably never paid much attention to the writing on the sides of your tires, but they contain a wealth of information.  There's a long combination of letters and numbers that can tell you a whole lot about what tires your vehicle was designed to be riding on.  Let's check out this example found on an SUV: P245/70R17 108T.

The first letter, P, means it's intended for passenger vehicles.  If there's no letter, it means it's a metric tire.  If there's an LT at the beginning or end that means a tire designed for light trucks.

Moving on to our example, the 245 shows how wide the tire is in millimeters from sidewall to sidewall.  The number that follows in our example, 70, means the height of the tire is 70% of its width.  The letter after that in our example, R, describes the type of tire (on this vehicle, radial).  Following that is the diameter in inches, in our SUV example, 17 inches. 

How much load the tires' sidewalls are designed to take is what that next number is all about (108 in our example).  The higher the load index, the more weight the sidewalls can take.  And the last letter is the speed rating of the tire, in our example, T.  The further along in the alphabet that letter is, the higher its speed rating.  So now you know what those letters and numbers mean.  But why are they important?

When you are getting ready to replace those tires, those numbers are telling you what the original equipment was when your vehicle was new.  Sticking with the same rated tires is always a good idea.  If you don't know what you're doing, trying different sized tires and wheels can cause real issues when it comes to performance and safety, considering all the computerized systems now found on vehicles.  When in doubt, consult your service advisor when it comes to buying new tires.  He or she knows what those tire numbers and letters mean… and a whole lot more.

Chimo's Auto Repair
9425 Wicker Ave
Saint John, IN 46373
(219) 365-6945
http://www.chimosautorepair.net



Search



Archive

August 2016 (17)
September 2016 (4)
October 2016 (5)
November 2016 (4)
December 2016 (4)
January 2017 (5)
February 2017 (4)
March 2017 (4)
April 2017 (5)
May 2017 (4)
June 2017 (4)
July 2017 (5)
August 2017 (3)
September 2017 (3)
October 2017 (4)
November 2017 (5)
December 2017 (3)
January 2018 (5)
February 2018 (4)
March 2018 (4)
April 2018 (4)
May 2018 (5)
June 2018 (4)
July 2018 (5)
August 2018 (4)
September 2018 (5)
October 2018 (4)
November 2018 (4)
December 2018 (4)
January 2019 (5)
February 2019 (4)
March 2019 (5)
April 2019 (4)
May 2019 (4)
June 2019 (5)
July 2019 (4)
August 2019 (4)
September 2019 (5)
October 2019 (4)
November 2019 (4)
December 2019 (5)
January 2020 (5)
February 2020 (4)
March 2020 (5)
April 2020 (4)
May 2020 (5)
June 2020 (4)
July 2020 (4)
August 2020 (5)
September 2020 (4)
October 2020 (4)
November 2020 (5)
December 2020 (4)
January 2021 (6)
February 2021 (4)
March 2021 (4)
April 2021 (4)
May 2021 (5)
June 2021 (4)
July 2021 (4)
August 2021 (5)
September 2021 (4)
October 2021 (5)
November 2021 (4)
December 2021 (4)
January 2022 (4)

Categories

Air Conditioning (6)Alignment (12)Alternator (1)Auto Safety (2)Automotive News (7)Battery (7)Brakes (7)Cabin Air Filter (2)Check Engine Light (3)Cooling System (11)Dashboard (2)Diagnostics (3)Diesel Maintenance (1)Differential Service (2)Drive Train (7)Engine Air Filter (2)Exhaust (6)Fluids (10)Fuel Economy (6)Fuel Saving Tip: Slow Down (1)Fuel System (29)Headlamps (3)Inspection (2)Keys to a long lasting vehicle (2)Maintenance (43)Monitoring System (2)Oil Change (1)Older Vehicles (1)Parts (6)Safety (4)Serpentine Belt (3)Service Intervals (6)Service Standards (8)Shocks & Struts (4)Spark Plugs (1)Steering (7)Suspension (2)Timing Belt (4)Tires (3)Tires and Wheels (31)Transmission (6)Warranty (1)What Customers Should Know (22)Wheel Bearings (1)Windshield Wipers (6)Winter Prep (1)