Bridgestone Tour

Bridgestone Tour

Tire FAQ

Generic Auto Tire FAQ
edited by Bill Del Vecchio
target = "_blank"> Generic Auto Tire FAQ

Introduction:

This FAQ (Frequently Asked Questions) is met to address some of the most common questions received at the forum on Compuserve CARS rationale for choice of tires, size and shopping. Try to give an overview covering typical consumer concerns when shopping for DOT approved tires for passenger car in the U.S. and / or Canada. The unaffected variations are greater, in historical terms, the designations of the United States, the tires of trucks and other specialty applications.

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Table Content

1. What do all those brands that side?
A. Size (ie 205/60-15)

B. Index rate (ie, M, V, Z)

Load C. Index (ie, 89, 92, 94)

D. UTQG Rating (temperature, traction, wear)

E. M & S Designation

F. Max. Load

G. Max. Press

H. Construction Type

I. Serial Number DOT

J. Date of manufacture (ie 134) 2. Tire Care: Inflation and rotation

3. Alternate Sizing
A. Why Do It?

B. How do I calculate the height and tire rotations per mile?

C. Can I put wider tires values in my tires?

D. What 's a Plus One, plus two or Plus Three conversion? 4. Buying Tires
A. What brands and models are best?

B. What are important factors to consider when choosing tires?

C. How do I choose between Performance, Touring and all seasons?

D. What all are the best seasons in the snow?

E. Where should I buy my tires? 5. What about snow tires?

6. What about buying new wheels and tires?

7. What about tires for my all land or 4x4?

7. Sources FAQ, Bibliography and Revision History

8. Copyright and Other Important Information

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1.A. How do I read a tire sidewall to tell its size?

The tire size is expressed in the format WWW / AA-DD (ie 205/60-15), where WWW is the tire sidewall-to-sidewall Width in mm (205), AA is the aspect ratio or profile of tire, which specifies the height of the tire as a percentage of its width (60% of 205 = 123mm) and DD is the diameter of the wheel that the tire is mounted in inches (15 inches). If the size P205/60R15 is shown as the "P" stands for passengers and the "R" is for the construction of structure radial. Note that it does not measure the width of the tread, which can vary significantly between the nominal width tires, even within product lines the same manufacturer.

What happens to an old tire that does not show an aspect ratio?

For more tire without an aspect ratio (ie 175R13), generally assumed to be a 78 or 80 series tire (ie 175/78R13 or 175/80R13). Note that for some European tire models, the ration default is 83. Fortunately, the practice of not listing the aspect ratio is becoming less and less common.

1.B. Speed Rating

The speed rating is traditionally shown as a part of size tire, ie "205/60VR15. Since the inclusion of payloads (see below 1.C), many manufacturers are showing the level speed after the size in combination with the carrying capacity, ie "205/60R15 92V. Most common speed ratings are:

Certificate

Top Speed Rating

N 87 mph

Q 100 mph

S 112 mph

T 118 mph

U 124 mph

H 130 mph

V 149 MPH *

More of 149 mph Z

W 168 mph

And 186 mph

* Originally, V was "more than 130 mph. "W and Y ratings are relatively new, therefore, redundancy with Z, which will probably be decommissioned sometime in the future.

1.C. Load Index

The load index indicates the maximum weight the tire can carry at maximum speed indicated by its classification speed. Examples of load indices Rating:

Rating Capacity (lbs)

75 853

82 1,047

85 1,135

87 1,201

88 1,235

91 1,356

92 1,389

93 1,433

105 2,039

1.D. UTQG (Uniform Tire Quality Rating)

... rates three aspects of tire performance, temperature, traction and wear. These ratings are usually located on the sidewall of the tire. Tire manufacturers do their own tests UTQG and assign their own grades. Some variations in testing are inherent due to the lack of controls. Fwiw, experts agree that wear is usually consistent within a given manufacturer of product lines.

Temperature: A / B / C

Displays the capacity of the tire to dissipate heat and its resistance to heat generation. "C": that the tire meets the minimum federal standards measured in laboratory tests, while "B" and "A" indicate performance increasingly well above the government minimum.

Drive: A / B / C

The degrees of humid straight braking performance. One is the best, C is the worst.

WEAR: Numeric Rating

Rates the tire against a standard control with a definite classification of 100 when running on a test course. A score of 300, for example, indicates that the tire will give three times the mileage control wheel. A score 60 is to be carried out in 60% of the control tire mileage.

1.e. M & S Designation

Indicates an all season tire designed for use in mud and snow. Note that this * not * mean that this is a "snow tire" (see Section 6).

1.F. Max. Load

This is the maximum static weight, generally, both in pounds and kilograms, the tire can withstand.

1.G. Max. Press.

The maximum pressure (usually in PSI and kPa) as the tire is designed to handle. This account is not the recommended pressure, which is set by the vehicle manufacturer and indicated in the owner's manual, and on a sticker on the doorjamb or glove box lid (see Section 2).

1.h. Construction

The number and composition of the tread and sidewall sheets are listed on the side, for example:

Layers of the tread: 2 polyester fabric SWR + 1 + 1 cable nylon

Layers of the side walls: 2 Polyester Cord

1.i DOT Number series

All tires approved for street use in the U.S. by the Department of Transportation will display a serial number of the DOT.

1.j. Date of Manufacture

All tires are coded to indicate the week of manufacture. Look for a three digits after the DOT serial number. The date code is stamped rather than molded. The first two digits are the week of the year in which the tire was produced (01 to 52), followed by the last digit of year of manufacture. A tire marked "134" was manufactured in week 13 (week April 4 in this case) 1994.

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2. Tire Care: Inflation and rotation

What inflation pressure should I use in my tires?

As indicated in 1.G. above recommended pressure the tires are set by the automaker, not the tire manufacturer. They are declared in the owner's manual and on a sticker on the doorjamb of the door or the glove box lid. It is important to frequently check the pressure at least once a month - more often if you find that you are losing pressure. For consistency, always measure pressures before driving when tires are cold (stationary for at least four hours, preferably overnight).

Tire pressure affects your car as follows:

Lower pressures higher pressures

Travel more comfortable rigid

Less precise handling and a better sense turn-on

More wear at the edges in the center

Performance of lower gasoline (less rolling resistance)

Tracking constant tends to follow the grooves

Many automakers are conservative (low) with its recommended pressure to maintain a comfortable ride. Drivers who push their cars pretty hard usually prefer a slightly more high. If you want to experience, 32 years of anything is a good starting point - not fit to start their own preferences.

The outside temperature affects the pressure tire, a general rule is that a 10-degree Fahrenheit change for tire pressure of 1 psi. When temperatures fluctuate, check their pressure more often. And if you check in a heated garage, set for temporary workers colder outside.

How about the rotation?

Recommendations for the patrons of tire rotation and mileage intervals vary: Owners of verification of your car manual and the tire manufacturer's recommendations for some guidance. As a rule, rotation is recommended at least every 10,000 miles. It may be prudent to rotate more frequently if you are using ultra high performance tires that wear quickly, or if the suspension settings of your car tend to wear down the tires on one end of the car at a much faster pace. Many people find it convenient and a useful reminder to rotate the tires, along with their oil change schedule, every 7,500 miles for the typical car or every other change for those with more frequent changes. YMMV!

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3.A. Alternate Sizing - Why do it?

Variations OEM tire size are usually done to improve the car handling and performance. Except for snow tires (see Section 5), a common goal is to get a wider tire and / or shorter side without changing the overall diameter of the rim. Wide-tread surface changes tire contact and can lead to a great improvement in handling. In general, more rubber on the road provides a better grip. A shorter sidewall (aspect ratio below) provides less flexible that can improve turn-in, responsiveness and stability. Keeping the overall height of the tire as close to stock reduces the possibility that changes the impact of the accuracy of the automobile speedometer and odometer, changes in general, the dynamics of the suspension and removal introduce potential problems.

Please note: With any change in the size of the OEM, the distance between the tire, fender, defense wells and suspension components is a vital concern. They also expect that changes in tire sizes calculated, whenever possible, measure the real, mounted tires.

3.B. How do I calculate the height and tire rotations per mile?

Theoretical height of a tire in inches is calculated as follows:

Height = (W x (Ratio/100) x 03,937 x 2) + Rim Diameter

The width multiplied by the aspect ratio of more than 100 gives the height in millimeters, multiplied by 03,937 converts to inches, and duplicate what explains the fact that no There are tires on the bottom and the top of the rim.

Rotations Per Mile (RPM) can be calculated as follows:

RPM = (inches per mile) / circumference of the tire

= (5280 * 12) / (Height * 3.1416)

= 20,168 / Height

Some sample calculations of the height of the tire and RPM are shown below:

Height error RPM @ 60MPH Note:

205 60 15 24.69 817-60.0 Stock size

225 55 15 24.74 815 0.2% 60.1 wide tire on the Action

225 50 16 24.86 811 0.7% 60.4 Plus One

245 45 16 24.68 817 0.0% 60.0 Plus One

245 40 17 24.72 816 0.1% 60.1 Plus Two

245 35 18 24.75 815 0.3% 60.2 Plus Three

185 65 15 24.47 824 -0.9% 59.5 alternative snow tire

It may be useful to establish a simple spreadsheet to determine the options. Height and RPM calculations stated above, while the error and speed of 60 mph in a given are calculated from the RPM compared to population size. An error of less than 1% almost always indicates a very good game.

3.C. Can I put wider tires on my stock rims?

The cheapest way to collect additional performance is usually to get a slightly wider tire with a lower aspect ratio for use at the edge of values. For example, a stock 205/60-15 tire can be replaced by a 225/50-15, almost no change in overall diameter. Note well that in addition to considerations of settlement listed above, the width of the tire market should also be able to accommodate the wider tires. Width edge A 6 "easily accommodate a tire of 205/60, but is at the low end of recommended rim widths for most manufacturers 225/50 tires. Whenever possible, seek advice the tire manufacturer or other owners of your vehicle to see the width of the tire rim can accommodate values.

3.D. What is a plus one, plus two or three Plus conversion?

Also shown as "+1", "2" or "3", These designations indicate the change of tires in stock for wheels 1, 2 or 3 inches larger diameter. Go to a larger diameter rim, keeping the height of the tire general about the same tire may allow significantly shorter, which can have a dramatic effect on the handling of a car, ride and appearance.

As shown in 2.B. above, possible replacements for 205/60-15 action can vary from a judicious mix 1 as 225/50-16 to 245/35-18 rather outrageous conversion to a +3. Note that price increases are not linear, although 18 and even 19-inch rims and tires are available, can cost several times what a 15 or 16 inches of installation will run.

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4.A. Buying Tires - What makes and models are best?

There is no "best" options. What is good for you is highly dependent on your car and your preferences. With this in mind, here is a comprehensive list of some of the tires most frequently recommended by users of the forum cars by type:

Ultra High Perf: Pirelli PZero, Bridgestone Expedia

High performance: D40M2 Dunlop SP8000 * and * Yokohama AVS Intermediate * and * A509, P700Z Pirelli, Bridgestone RE71, BF Goodrich Comp T / A 3, Goodyear GS-C

Touring Pirelli P4000 M & S, Bridgestone Turanza M & S, Yokohama A378

All season: * Dunlop D60A2, P500 Pirelli, Yokohama AVS U +4 Michelin XGT V4

Race / Autocross: Yokohama A008 and A008 * RS RS II, BF Goodrich Comp T / A R1 (226 and 230 compounds), Goodyear GS-CS

* CARS All-Stars - more frequent positive comments user satisfaction

4.B. What are important factors to consider when choosing tires?

The best tire depends on a variety of factors, and more specific might ask a professional for advice, the best advice you might receive:

• What kind of car, truck or van you driving?
• What is the stock tire size? Are you considering a change?
• How do you drive? Is his driving style aggressive, passive or middle?
• When you drive? City, road, roads, mountains, on the track?
• In what kind of weather? What is the climate of the region? Is the car used throughout the year? How much snow or heavy rain you get?
• What is most important to you? How to prioritize traction, comfort, durability, steering response, handling and noise?
• What is your estimated price? How important is value in comparison with the elements of performance tires above priority?
• Do you have any particular brands or models in mind? Have you had good or bad experiences with any of the models in the past? How do your current tires?

4.C. How do I choose between performance, Touring and all stations?

Resistant question! Here are some random thoughts and notes to help:

• Ultra high performance tires provide more traction and performance that can be used safely on the street. It is a waste of money for most drivers and most cars unless they are used as a dual purpose road / tire racing. Tire life of 10,000 miles will be expected in some car models.
• High-performance tires also provide more traction and performance a responsible driver should use on the street. But in doing so, increase the margin of safety in emergency driving maneuvers. There are some very competitive, cost-effective models in this classification is not necessary to spend much money to get a dramatic performance and improved security in the original equipment tires.
• The "Touring" designation is relatively new. Definitions may vary among different manufacturers, but most artists are marketed as over the relevant years "that are better than all seasons of driving performance and better tire performance in slippery conditions.
• A true all seasons has a "M + S" (mud and snow) designation of the sidewall. All Seasons usually much better than the tire performance in mud, snow or sleet, but it is a misconception that also do better in wet conditions. In tire testing (see Section 7), performance tires did better in wet handling and braking at all stations. In general, all seasons are a compromise that let use the same year, the tires all year, even when snow is expected. Use of performance tires and a set of snow tires (see Section 5) is recommended by many forum regulars CARS.

4.C. That all the best seasons in the snow?

Richard Engel [76,614.3653] pneumatic tank in Edmonton, Alberta offered the Dunlop D65, Axiom and Sport 4000, Pirelli P300 and Yokohama Y370/Y378 several leading professionals in the snow but is quick to remind everyone that for the best traction, you need a set of winter tires.

4.D. Where do I buy my tires?

Perhaps the best way to buy tires is to find knowledge, a local store that has reasonable prices, staff competent service, modern equipment and give honest advice. For national chains, Super Stores have been recommended as a great place on all counts. Festival tents tire in the Northeast sometimes have good prices if you negotiate, but their recommendations are often biased by what is profitable, storage and service can be spotty.

Among the mail order companies, the rack of tires (800) 428-8355 has been recommended hundreds of times for good advice, excellent availability and very competitive prices. If you call, ask for Robert Scott in x307 or x343. Tire Rack also has an Internet presence Tire Rack - Your performance experts for tires and wheels - It was new 4 / 96, but with an interface very impressive, with good content, and (very) quick operation. Highly recommended!

Discount Tire Direct at (800) 707-8473 also has outlets and not his best to beat Tire Rack prices and delivery. TeleTire (800) 835-8473 does not carry as many manufacturers as some other companies but also committed to trying to give the best price. EuroTire (800) 631-0080 has orders by phone, in addition to selling through their stores, but carries a selection Limited brand.

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5. What about snow tires?

For snow tires, narrower and higher usually works better than the tire size of values, and some experts recommend considering a "minus one" conversion, especially for vehicles with wide tires. The calculations shown in 2.B. above are also used to determine the limited size of snow tires and Minus One conversions, ie:

Height RPM * Error @ 60MPH Note:

275 40 17 25.66 786-60.0 Stock size

205 60 16 25.69 785 0.1% 60.1 Minus One

Height RPM * Error @ 60MPH Note:

205 50 15 23.07 874-60.0 Stock size

185 55 15 23.01 876 -0.3% 59.8 Narrow Snow tire in stock Rim

For serious driving in the snow, regular or all-season tires are no match for a good set of four snow tires. Among the members of Car Forum, the most frequently cited models are the 190P and 210P Pirelli and Bridgestone Blizzak. The Pirelli is a very good all-around choice for a snow tire dry with a reasonable return and the expectations of wear, and the new Pirelli S / P is a good choice for a grave duty tires studdable.

The only Blizzaks recently introduced, but I have a lot of fans. They provide great traction on slippery surfaces, but its dual compound tread design means it can not be a good choice for all situations. Once the Blizzak of the tread is worn below 55%, is designed to work as all-season tires instead of a snow tire. This may work well for someone who puts the annual high mileage in your car, hopes to replace their tires a year and would prefer not having to maintain a second set of tires. With the purchase of a new set of Blizzaks in late autumn, you can ensure optimum traction on snow throughout the winter. As tires wear, you get a competent all-season use until the replacement cycle comes. As an alternative, someone who gets low mileage in your car can maintain a set of Blizzaks through several winters with the installation of them just before the beginning of the snow removed in early spring.

Nokia Hakkapeliittas deserve special mention, perhaps premium snow tires that are used by rallyists more than any other brand. Due to the limited distribution, may be difficult to find, but several forum members have recommended Greer Companies in Milwaukee (414-744-0996) as a source for tires for Nokia.

Is it necessary * * four snow tires?

The question 2 vs 4 snow has been raised several times. Although the convent IONAL wisdom used to be that the snow put the drive wheels was not enough, the key recommendations have recently been using all four. Why? The main concern is that the snow and the seasons have all the handling characteristics dramatically different.
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