Getting to Know Your Tires

Posted on May 1, 2008 by Wayne Blanchard

MOST PEOPLE BUY TIRES without ever knowing what the data on the tires mean. When we see a size of 235/70 R 16 101 S, most of us are lost. How do these numbers affect your vehicle? Why are they so important? How do you know that the tire you’re being sold is actually the correct tire for you? Here’s the tire data simplified.

1 • SECTION WIDTH: This (235) indicates the distance (in millimeters) across from the widest point of the sidewall exterior to the widest point of the inner sidewall when mounted on the proper rim. A tire that is too thin may not inflate properly on the rim, and one that is too wide may damage the rim and wheel well.


2 • ASPECT RATIO: This means that the (70) indicates that the height from the sidewall to the tread is 70% of its section width. Basically, the higher the number, the taller the sidewall, and the lower the number, the shorter the sidewall. Too short a sidewall can cause rim damage and create a poor ride. One that is too tall can “rub” and cause damage to surrounding body panels.


3 • TYPE OF CONSTRUCTION: An R indicates that the tire is a radial, which means the tire’s body plies “radiate” out from the center of the tire.


4 • RIM DIAMETER: This (16) is the measurement of the rim from inner bead wall to inner bead wall. Only tires of like size will fit your rims.


5 • LOAD INDEX: This (101) is the maximum weight capacity of your tire. When multiplied times four, you get the total weight of your vehicle and passengers the set of tires can carry. Example: load index of 99 = 1,709 lbs. per tire x 4 = 6,836 lbs. total. For load ratings, see chart below.  


    LOAD INDEX        LOAD (LBS)         LOAD INDEX          LOAD (LBS)    
65 639 85 1135
66 661 86 1168
67 677 87 1201
68 694 88 1235
69 716 89 1279
70 739 90 1323
71 761 91 1356
72 783 92 1389
73 805 93 1433
74 827 94 1477
75 852 95 1521
76 882 96 1565
77 908 97 1609
78 937 98 1653
79 963 99 1709
80 992 100 1764
81 1019 101 1819
82 1047 102 1874
83 1074 103 1929
84 1102 104 1984


6 • SPEED INDEX: This (S) indicates the top speed your tires are rated for. An S rating, for example, indicates a maximum of 112 mph.


Tires that have a higher rating are generally made with a stronger compound and contain a reinforced sidewall. Any tire that is high load rated will most likely have the word “REINFORCED” imprinted into the tire sidewall.


View comments or post a comment on this story. (0 Comments)

More News

Parent Company Of MCI Soars Past $2 Billion In Revenue

New Flyer management said it expects to make and deliver about 3,650 new transit buses and motorcoaches during 2017.

Ford E-450 Minibus Will Provide A Safe Ride

Vehicle Pick of the Week: The First Class Customs creation has a variety of certifications that will please corporate travel buyers.

2018 Mercedes-Benz Sprinter Spied In The Wild

The large van last received an update for 2014, but we’ll be seeing a complete overhaul this time around.

A First Look At The Range Rover Velar

The company has begun accepting orders for the First Edition models, which are priced at $89,300 and limited to 500 in the U.S.

Genesis G80 Not As Strong As G90 Counterpart

The Hyundai sedan is a good warning the marquee is evolving quickly, keeping it on track with one day attaining the ranks of Infiniti or even Lexus.

See More News

Facebook Comments ()

Comments (0)

Post a Comment



See More

LCT Store

LCT Magazine - March 2017 $12.95 INT'L LCT SHOW ISSUE COVER STORY: * Innovate or Die: Show To Be a Business "Disrupter" * *
LCT Magazine - February 2017 $12.95 NEW MODELS ISSUE COVER STORY: * Fleet Vehicles Preview * *


Experience the three annual industry events for networking for business, showcasing vehicles and products, and getting the tools for success.

Read About Your Region

What’s Happening Near You?
Click on any state to see the latest industry news and events in that region.

More From The World's Largest Fleet Publisher

Automotive Fleet

The Car and truck fleet and leasing management magazine

Business Fleet

managing 10-50 company vehicles

Fleet Financials

Executive vehicle management

Government Fleet

managing public sector vehicles & equipment


Work Truck Magazine

The number 1 resource for vocational truck fleets

Metro Magazine

Serving the bus and passenger rail industries for more than a century

Schoolbus Fleet

Serving school transportation professionals in the U.S. and Canada

Please sign in or register to .    Close