Your Top Tire Questions, Answered

Learn Tire Basics From the Folks That Know Tires

What is TPMS?

The Tire Pressure Monitoring System (TMPS) is an electronic system in your vehicle that monitors your tire air pressure and alerts you when it falls dangerously low. This system alerts you with a tire pressure light on your dashboard when a tire needs inflation. It will not alert you if your tires are overinflated. To help drivers recognize the importance of tire pressure safety and maintenance, Congress passed the TREAD act, which requires most vehicles made after 2006 to be TPMS equipped.

What is my recommended tire pressure?

We recommend using the tire pressure that the vehicle manufacturer requires. This information is normally written on the inside driver’s door jam. We suggest you do not deviate from this tire pressure. Pressure requirements may change with plus sized tires. You can use the tire pressure lookup tool to view the manufacturer–recommended inflations for standard–sized tires on your vehicle.

Is it easy to see when my tire pressure is low?

No. Tire pressure is tough to judge on sight alone. Tires can be well under 50% inflated before it’s noticeable to the eye. This is why it’s so important to check your tire pressure monthly with an accurate tire gauge. Try to do so in the morning before they’ve been driven on in order to get the most accurate reading. 

Do my original equipment (O.E.) tires come with a mileage warranty?

No. O.E. tires are designed to the vehicle manufacturer’s specifications and do not offer a mileage warranty. However, your tires are warranted for workmanship. 

What is the rolling resistance of my tires?

Rolling resistance traditionally has been measured through SAE (Society of Automotive Engineers) test procedure J1269. It measures the force required to roll a tire against a dynamometer at a fixed speed of 50 mph.

There are more than 1,300 passenger and light truck products in the Bridgestone line alone — and conceivably, each one could have a different rolling resistance. The tread compound is a major factor, but construction, size, and even tread pattern can have an influence.

At least three tires must be run in each configuration to get a good average. At approximately one hour per rolling resistance test, this amounts to 3,900 hours — or over six months — just to run the Bridgestone brand.

This explains why these values are estimated. We do have some data, but most of the time it doesn’t line up with those sizes or patterns requested. Therefore, estimation is required. These estimates are made by independent organizations. Tires Plus does not test for rolling resistance.

What is speed rating?

A tire’s speed rating indicates the speed category (or range of speeds) at which the tire can carry a load under specified service conditions. The speed rating system used today was developed in Europe in response to the need to control the safe performance of tires at standardized speeds.

A letter from A to Z symbolizes a tire’s certified speed rating, ranging from 5 km/h (3mph) to above 300 km/h (186 mph). This rating system (listed below) describes the top speed for which a tire is certified. It does not indicate the total performance capability of a tire.

When this speed rating system originally was developed, the Unlimited V category of over 210 km/h (130 mph) was the top speed rating a tire could achieve.

As manufacturers made more tires that did not fit this category, it was necessary to better regulate performance at standardized speeds to ensure safety. The Limited V category of 250 km/h (149 mph) was then created, and the Z speed rating was added as the top speed rating that a tire could achieve. W and Y limited speed symbols have been added as higher speed categories.

Always consult the manufacturer for the maximum speed of Unlimited Z tires. Speed rating is identified as a part of the tire’s sizing or service description.

In the latest attempt to standardize tire designations, all ratings except Unlimited ZR incorporate the speed symbol and load index as the tire’s service description. For example:

205/60R15 91V
205 = Section Width in Millimeters
60 = Aspect Ration
R = Radial Construction
15 = Rim diameter in Inches
91 = Load Index Service Description
V = Speed Symbol

When "ZR" appears in the size designation with the service description, the maximum speed is as indicated by the service description:

Tire Designation Maximum Speed
P275/40ZR17 93W 270 km/h (168 mph)
P275/40ZR17 93Y 300 km/h (186 mph)

For tires having a maximum speed capability above 240 km/h (149 mph), a "ZR" may appear in the size designation. For tires having a maximum speed capability above 300 km/h (186 mph), a "ZR" must appear in the size designation. Consult the tire manufacturer for maximum speed when there is no service description.

What is the repairable area of a non-RFT (Run Flat) tire?

We only repair tires in accordance with the RMA (Rubber Manufacturers Association) recommended procedures. Some punctures cannot be seen with the naked eye, and other measures are taken to find such punctures (such as soapy water and tire water tubs).

Why did my tires wear so quickly?

Premature tire wear may be caused by many factors other than tire rotation. Some examples are as follows: improper inflation, driving conditions, misaligned vehicles, worn vehicle parts and a variety of other reasons.

Without physically inspecting the tires, it is difficult to make a determination as to why your tires wore prematurely. Please visit your nearest Tires Plus and have one of our trained professionals inspect your tires free of charge.

Does nitrogen make a difference in tires?

Recently, some tire shops and filling stations have been offering nitrogen (N2) as an inflation gas for passenger and light truck tires. Nitrogen is acceptable as an inflation gas for use in Bridgestone and Firestone passenger, light truck and truck tires.

Bridgestone and Firestone tire inner liners are designed to act as pressure retention devices — specifically with the use of air — providing durability for the life of the tire and restricting air loss due to permeability. Nitrogen will not cause any detrimental reaction to the inner liner. Tires Plus cannot confirm or deny the claims stated by various nitrogen suppliers.

Will you beat competitors’ prices?

Find complete details on the Tires Plus Price Match Guarantee.

I only need two tires. Do they go on the front or the back?

When replacing only two tires on your vehicle, new tires should always be placed on the rear of the vehicle. For a detailed explanation, view our Balancing and Mounting recommendations.

Still have tire questions?

Stop by your nearest Tires Plus and talk with a tire technician. Or, contact us by phone or email. We’d love to hear from you!

Find Store

Find a Different Location

Stores Near You

Do you want to change your Preferred Store?