Picture of a two Potenza tires

Learn About Tires

What is the proper inflation for my tires?

Tires Plus recommends using the tire pressure that the vehicle manufacturer requires. This information is normally written on the inside driver’s door jamb. We suggest you do not deviate from this tire pressure. Pressure requirements may change when plus sizing tires. You may use This Tool to view the manufacturer recommended inflations for standard sized tires on your vehicle.

What is the mileage warranty on my O.E. (original equipment) tires?

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 has traditionally 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 over 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 3 tires must be run in each configuration to get a good average. At approximately 1 hour per rolling resistance test, this amounts to 3,900 hours or over 6 months just to run the Bridgestone brand.

This explains why these values are estimated. We have some data, however it frequently does not 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 meant by speed rating?

The speed rating of a tire 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 was originally 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:

Tire Description for the 205/60R15 91V
205 = Section Width in Millimeters
60 = Aspect Ratio
R = Radial Construction
15 = Rim Diameter in Inches
91 = Load Index (Service
V = Speed Symbol

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

ZR Designation Examples

Tire Designation


Maximum Speed

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

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.

Tire Speed Capabilities - Indes of Speed Symbols
  A1   5   3  
  A2   10   6  
  A3   15   9  
  A4   20   12  
  A5   25   16  
  A6   30   19  
  A8   40   25  
  B   50   31  
  C   60   37  
  D   65   40  
  E   70   43  
  F   80   50  
  G   90   56  
  J   100   62  
  K   110   68  
  L   120   75  
  M   130   81  
  N   140   87  
  P   150   94  
  Q   160   100  
  R   170   106  
  S   180   112  
  T   190   118  
  U   200   124  
  H   210   130  
  V   240   149  
  W   270   168  
  Y   300   186  

What is the repairable area of a nonRFT (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 (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 many other reasons.

Without physically inspecting the tires it is difficult to make a determination as to why your tires wore prematurely. Please visit our location 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 innerliners 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 innerliner.

Tires Plus passes no judgment on the claims stated by various Nitrogen suppliers.

Will you beat competitors’ prices?

Our Priced Right Guarantee means we'll match any comparable service price, or we'll refund 200% of the price difference on your tire purchase within 30 days.

This guarantee extends to the Customer, within thirty (30) days after the date of purchase, a refund of 200% of the difference between a current locally-advertised lower price on a similar make/model tire and the price of a tire purchased from a Tires Plus store. Customer must provide a current local advertisement. This guarantee excludes clearances, closeouts and catalogs. This refund is not to be combined with any other offer or used to reduce outstanding debt.

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