Tire IQ

Tire Markings

Image showing the markings on a tire.



Used Tires

We do not recommend the purchase of used tires. No method exists to verify the service record of a used tire. Consider that internal damage from previous misuse may go unnoticed or improper repairs may have been performed. Such conditions could lead to an unexpected sudden tire failure. Used tires present an unreasonable risk to you and your family.


Inside Your Tire



Load Index and Related Loads


Load Index Load Lbs.
50 418
51 419
52 440
53 454
54 467
55 480
56 493
57 507
58 520
59 535
60 551
61 566
62 584
63 599
64 617
Load Index Load Lbs.
65 639
66 661
67 676
68 694
69 716
70 738
71 760
72 782
73 804
74 826
75 853
76 881
77 908
78 936
79 963
Load Index Load Lbs.
80 928
81 1,018
82 1,047
83 1,073
84 1,103
85 1,135
86 1,168
87 1,201
88 1,234
89 1,278
90 1,322
91 1,355
92 1,388
93 1,433
94 1,477
Load Index Load Lbs.
110 2,336
111 2,403
112 2,469
113 2,535
114 2,601
115 2,678
116 2,755
117 2,832
118 2,910
119 2,998
120 3,086
121 3,196
122 3,306
123 3,417
124 3,527



Tire Speed Symbol Markings


Speed Symbol Maximum vehicle speed for which tire is suitable
M 81 mph 130 km/h
P 93 mph 150 km/h
Q 99 mph 160 km/h
R 106 mph 170 km/h
S 112 mph 180 km/h
T 118 mph 190 km/h
Speed Symbol Maximum vehicle speed for which tire is suitable
H 130 mph 210 km/h
V 150 mph 240 km/h
W 169 mph 270 km/h
Y 187 mph 300 km/h
ZR over 150 mph over 240 km/h



Tire Age

Your tires are a complex combination of rubber, steel and chemicals. These chemicals help to bond the steel and rubber that make a pliable new tire. Over time the chemicals will degrade and the rubber inside your tire will become hard and inelastic. Though aged tires may not show signs of decay on the surface, they are a safety risk. Know the age of your tires and remove them from service if they were manufactured more than ten years ago.

To determine the age of your tires, find the last four digits of the DOT number stamped on the side of your tire. These digits correspond to the WEEK and YEAR of production. For example, “0210” indicates the tire was produced in the second week of the year 2010. All tires stamped with DOT numbers ending in just three digits are beyond serviceable life and require replacement. If you cannot find the DOT number or it faces the INSIDE of your wheel, visit a tire service professional who can determine the age.




Tire IQ – Maintenance


Tread Depth:

Knowing how much tread remains on your tires is critically important. Tread depth will directly impact how your vehicle performance on breaking, cornering and handling. Shallow tread can increase the risk of hydroplaning and lower resistance to common road hazards. Tires should be replaced when any part of the tread is below 2/32 inch (1.6 mm). Watch this video from the Rubber Manufacturer’s Association to learn a simple and fun method to check your tread using a copper penny. Click here to view video


When Replacing Two Tires or Less:

Replacement of four tires is always recommended. In cases where less than four tires are replaced on a vehicle, standard industry practice calls for REAR installation. This rule applies when the number of tires being replaced is two OR even just one. Worn REAR tires greatly reduce the driver’s ability to maintain control during a hydroplaning event. Always reference your vehicle owner’s manual for special instructions before replacing any number of tires.


Checking Tire Pressure:

Tire pressure should be checked every month and before long trips. Tire pressure should only be adjusted when your tires are cold. Never reduce the air pressure of a “hot” tire. Tires are considered “cold” when left stationary for three hours or driven less than one mile. Proper tire inflation pressure is determined by the vehicle manufacturer and is commonly found on the driver door placard or in the vehicle owner’s manual. Do not drive on under-inflated tires. Under-inflated tires risk catastrophic failure due to excessive heat buildup in the sidewall. Driving on under-inflated tires also reduces fuel economy. Do not drive on over-inflated tires. Over inflation will increase the risk of damage caused by road hazards. When adding air to your tires, never exceed the maximum inflation pressure listed on the tire sidewall. (RMA, www.rma.org) Click here for a video on how to check the tire pressure


Tire Pressure Monitoring System (TPMS)

Since September of 2008, all passenger and light trucks sold in the United States have been required by the National Highway Safety Administration (NHTSA) to be equipped with an electronic safety devise that monitors tire air pressure. The device is known as a “TPMS” or Tire Pressure Monitoring System. The purpose of this device is to provide the driver with advanced warning of air pressure loss in a tire. Most systems warn the driver of pressure loss through an amber “low tire” symbol on the dashboard like the one shown here. Though very useful, these systems cannot predict catastrophic pressure loss and are not a substitute for normal tire maintenance. Click here for a video on the TPMS warning light


Slow Leaks

Under normal driving and climatic conditions, your tires will lose around 2psi every 30 days. If you are adding pressure to your tires more frequently, your tire may have a slow leak. Visit your tire service professional and have the complete tire and wheel assembly inspected. Repair or replace the tire(s) as required.


Tire Repairs

Know the difference between a “proper” tire repair and an “improper tire” repair. Improper tire repairs are hazardous to everyone. Insist that your tire professional use repair methods which meet the minimum requirements established by the Rubber Manufacturer’s Association. The basic requirements are stated below

  • Tire must be removed from the wheel assembly for complete inspection, inside and out
  • Repairs must be limited to the tread area only
  • Puncture diameter cannot exceed ¼-inch (6mm)
  • Repairs cannot overlap
  • A “patch-plug” style repair must be used

Click here for a video on proper tire repair from RMA


Spare Tire Care

Most drivers only think of the spare tire when they need it. Unfortunately many drivers also neglect to routinely check the air pressure in the spare tire. Avoid the surprise of an underinflated or flat spare tire by checking the pressure every 30 days with the other tires. This rule applies to small “tempa” spares as well as full size spare tires. Note that many Vans and SUV’s have the spare tire mounted under the vehicle where checking inflation pressure can be difficult. Insist that your tire professional check the spare tire pressure on every visit.


Tire Balancing & Wheel Alignment

Tire balancing and wheel alignment are necessary part of routine tire maintenance. Have your balancing and alignment checked according to the vehicle manufacturer’s recommendations. Between routine maintenance checks, look for signs that your vehicle is in need of tire service. Warning signs can include irregular tire wear, vibration, off center steering wheel and “pulling”.


Tire Rotation

Regular tire rotation is necessary to maximize your tire’s tread life as well as maintain even tread wear throughout the service life of your tires. Tire rotation is also required to maintain the manufacturer’s warranty. The frequency and pattern of your tire rotation is determined by the vehicle manufacturer and can be found in the owner’s manual. Special rotation patters may be applied to vehicles with directional tire treads, dual rear wheels or vehicles equipped with staggered tire fitment. If your tires show signs of irregular or excessive wear between rotations it may indicate an alignment or balancing problem and you should see a tire service provider. Click here for a video on tire rotation


Cleaning Your Tires

Tires can be cleaned using mild household detergent. Visit your local auto parts store for tire cleaner, dressing (shine) and a soft bristle tire brush. Cleaning your tires and applying a dressing not only helps improve your vehicles appearance but also helps to preserve the sidewall.


Staying Informed

Stay informed about common tire safety issues by following the RMA’s “Be Smart Do Your Part” Twitter feed.
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