Guide

Safety Warning – Speed Rated Tires

The following is current information regarding speed rated tires. Please note that many of today’s vehicles are equipped with speed rated tires. Please not that many of today’s vehicles are equipped with speed rated tires. It is NOT recommended that tires on these vehicles be replaced with tires which exhibit a lower speed rating than those specified by the vehicle manufacturer.

Safety Rules for Selection, Mixing, Repairing, Retreading, or Alteration of Speed Rated Tires

It is important, for the safety of the consumer, that the following safety rules be followed in the selection, mixing, and servicing of speed rated tires.

A. When replacement of tires is desired, consult the placard (normally located on the door frame or glove box door) or the owner’s manual for correct size. If the tires shown on the vehicle placard do not have speed ratings, the appropriate size tire with any speed rating may be applied, if desired. When the placard tire size nomenclature contains a speed symbol, for example P205/60HR15, the replacement tire must have the same or higher speed rating symbol if the speed capability of the vehicle is to be maintained. If the replacement tire is not speed rated, or has a lower speed rating than indicated on the vehicle placard, the speed capability of the vehicle is limited by the speed capability of the replacement tire. A Mickey Thompson produced dot tire without a speed rating has a max highway speed of 85 mph.

B. Mixing

If tires of different speed ratings are mounted on a vehicle, the tire with the lowest speed rating will limit permissible tire related vehicle speed. If any replacement tire is not speed rated, the speed capability of the vehicle is limited by the maximum speed of that tire (85 mph for Mickey Thompson produced tires).

C. Retreading, Repairing , or Alteration of Speed Rated Tires

Speed rating no longer applies to a mickey thompson produced tire that has been altered (for example, by retreading or repairing).

Service Life of M/T Tires

Understanding The Service Life Of Your M/T Tires

DETERMINING THE AGE OF A TIRE

The manufacturing date of a tire is incorporated into an 11 digit code, called a TIN (Tire Identification Number) located down by the bead of the tire. The only exception would be most Pro Drag Radials, which do not incorporate traditional TIN’s. On street legal tires, the TIN is preceded by the letters “DOT”. The last four numbers of the TIN represent the week and year of manufacture. In the Example below, this tire was produced the 35th week of 2017. EXAMPLE: CY1JM5FJ3517 (3517 = date code)

THE SERVICE LIFE OF YOUR M/T TIRES IS NOT ENTIRELY DICTATED BY CHRONOLOGICAL AGE.

All M/T tires are designed with conscience efforts to maximize tire life with maximum performance. That being said, the useful life of a tire is a function of its use, application, and storage conditions. Since these elements can vary widely, and are not controlled by the manufacturer, accurately predicting the life of any specific tire based on calendar age is near impossible.

However, with that understanding Mickey Thompson does recognize the benefit of a uniform approach regarding the service life issue. Accordingly, M/T has come up with the following age criteria for removing tires from service. These dates are based from the manufacturing date.

Race Tires – 4 years.
Bias Truck Tires – 8 years
Radial Light Truck Tires – 10 years
Passenger Tires – 10 years

Under no circumstances should these recommendations be consider as an “expected” service life. Most tires will need to be replaced before these time limits are met due to service conditions.

Tires can be removed for several reasons, such as:

Tread worn down to the minimum depth
Signs of damage (cuts, cracks, punctures, impact damage, etc)
Abuse (Long sustained burnouts, overload/under-inflation, improper repair etc)
Weather checking
Misapplication
Performance levels falling off.

TIPS FOR MAXIMIZING THE LIFE OF YOUR M/T TIRES.

GENERAL

Proper inflation pressure and rim widths. This will help evenly distribute the load across the contact patch and even out wear.
Inspect the tires for damage such as cuts, leaking valve stems, or punctures.
If the vehicle is not frequently used, keep the tires out of direct sunlight.
Proper balance and alignment.

RACE TIRES

Rotate the tires as often as you can. If they “feather” too much in one direction, they may take a run or two to come back. This also means they should be rotated more often.
Never let the tires sit flat or at low inflation pressures while under load on the car. Put the car up on jacks, or remove the tires and store them on their side.
Tubes at times can help extend the tire life.

Diameter, Rollout (Circumference) And Revolutions Per Mile Chart

DIAMETER, ROLLOUT (CIRCUMFERENCE) AND REVOLUTIONS PER MILE CHART

Below is a chart to assist in vehicle drive-train calculations.

Diameter	Rollout	Revs/Mile*
17.5	55	1222
18	56.5	1186
18.5	58.1	1152
19	59.7	1120
19.5	61.3	1090
20	62.8	1061
22	69.1	960
22.5	70.7	938
23	72.3	917
23.5	73.8	896
24	75.4	877
24.5	77	858
25	78.5	840
25.5	80.1	823
26	81.7	807
26.5	83.3	791
27	84.8	776
27.5	86.4	761
28	88	747
28.5	89.5	733
29	91.1	720
29.5	92.7	708
30	94.2	695
30.5	95.8	684
31	97.4	672
31.5	99	661
32	100.5	651
32.5	102.1	640
33	103.7	630
33.5	105.2	621
34	106.8	611
34.5	108.4	602
35	110	593
35.5	111.5	585
36	113.1	576
36.5	114.7	568
37	116.2	560
37.5	117.8	553
38	119.4	545
38.5	121	538
39.5	124.1	524
40	125.7	517
45.5	142.9	453
46	144.5	448
53	166.5	388
53.5	168.1	384
54	169.6	381

*Based on approximate loaded radius.

Passenger and Light Truck Used Tires

Consumers should be aware of possible serious risk associated with the installation and use of previously used tires. While tires are designed and built to provide many thousands of miles of excellent service, they must be maintained properly throughout their service life to achieve optimal performance. Proper tire maintenance includes regular (at least monthly) visual tire inspections for signs of damage or abuse (ie. Cuts, cracks, bulges, snags, irregular wear, etc.) and inflation pressure checks. Tires can be damaged over the course of their service life due to abuse or improper service, maintenance, repair, or storage conditions, and such damage can eventually lead to tire failure. Only the original owner of a new tire can know the full extent of a particular tire’s service and maintenance, and the conditions of use or abuse the tire has experienced. Thus, Mickey Thompson Tire fully endorses the RMA Tire Information Service Bulletin, “Passenger and Light Truck Used Tires”.

Mickey Thompson urges that used tires should not be purchased, sold, or installed if they exhibit any of the conditions listed in the RMA bulletin, or if the used tires are offered by anyone other than a qualified tire service professional at a reputable new tire sales facility. Also, it should be noted that any used tire deemed not suitable for immediate service is also not suitable for spare tire applications. When a faulty spare tire is eventually used, it will be dangerous in service.

Consumers should also be wary of used tires that:

May have been used on vehicles involved in an accident
May have been used in sever service conditions (e.g. used for off-road, sporting, military or law enforcement purposes)
May have been exposed to unusual environmental conditions such as sever storms, floods, fires, etc

Tire Inflation - Nitrogen

Nitrogen inflation in tires is gaining popularity in the light vehicle (passenger and light truck) market. Nitrogen inflation in tires is not new to the tire industry however, and has been used under severe service conditions such as in large off-road tires, aircraft tires (as fire prevention) and racing tires for many years. Nitrogen inflation does not harm tires nor does it affect the warranty.

One of the most important factors in tire care is maintaining proper inflation pressure. The proper tire inflation for a vehicle is specified by the vehicle manufacturer and can usually be found on the tire placard (or sticker) attached to the vehicle door edge, door post, glove box door or fuel door as well as the vehicle owner’s manual. Proper tire inflation, whether nitrogen or normal air, helps tires wear longer, saves fuel and helps prevent accidents. Under inflation, regardless of the inflation gas, can make it harder to steer and stop your vehicle, result in loss of vehicle control, cause sudden tire destruction, and lead to serious injury or death.

Nitrogen inflation will not prevent damage or loss of inflation due to road hazards. Nitrogen inflation will also not prevent tire damage due to under inflation, overloading of off road service. Tire inflation should always be checked and adjusted to proper inflation pressure on a regular basis (at least monthly and before long trips), regardless of the inflation gas, to provide optimum tire performance.

Tire Mixing

When tires need to be replaced, do not guess what tire is right for the vehicle. You must consult the tire placard, which is normally located on the vehicle door edge, door post, glove box or fuel door. The placard tells you the size of the tires (including the spare) that were mounted on the vehicle as original equipment (OE). It also includes the recommended cold inflation pressures for the front/rear axles and the spare tire as well as the load capacity. If the vehicle does not have a placard, check the owner’s manual or consult with the vehicle manufacturer or tire manufacturer.

IMPORTANT: Always check the vehicle manufacturer’s recommendations for the OE tire size, load capacity, inflation pressure, and speed symbol information before replacing a tire with a different size and construction. It is not always possible – usually due to temporary emergency conditions – to select the same tire size for a replacement tire. Never choose a smaller size replacement tire and/or a tire with less load carrying capacity than the specified size on the vehicle placard. The RMA provides the following insight for emergency/temporary nonstandard fitments:

The following is a passage from the RMA Replacement Guidelines for Passenger & Light Truck Tires manual.

TIRE MIXING

It is recommended that all four tires be of the same size, speed rating, and construction (radial, non-radial). In some cases the vehicle manufacturer may require different sized tires for either the front or rear axles. NEVER mix P-Metric or European Metric passenger tires with light truck sized tires on the same vehicle.

Match tire size designations in pairs on an axle, except for temporary use of a spare tire. (See Mickey Thompson Tech Bulletin #15 “Replacing Less Than Four Tires”).

If two radial tires and two non-radial tires must be used on a vehicle, put radials on the rear axle. If radial and non-radial tires are used on a vehicle equipped with dual rear tires, the radial tires may be used on either axle.

Speed rated tires – If the vehicle tire placard and/or owner’s manual specify speed rated tires, the replacement tires must have the same or higher speed rating to maintain vehicle speed capability. If replacement tires have lower speed capability than specified by the vehicle manufacturer, the vehicle’s speed must be restricted to that of the replacement tire. Also, vehicle handling could be affected. Consult vehicle manufacturer or tire manufacturer for recommendations – and consumers should know the speed must be restricted to the limits of the replacement tire. With the exception of winter/snow tires (see below), if tires with different speed ratings are used, it is recommended that the lower speed rated tires should always be placed on the front axle. This is to prevent a potential oversteer condition.

Four-wheel drive (4WD) and All-wheel drive (AWD) vehicles

If no instructions for tire mixing appear in the vehicle owner’s manual, follow these guidelines:

DO NOT mix tire sizes. All four tires must be marked with the same tire size, unless otherwise specified by the vehicle manufacturer. This also applies to winter/snow tires.
DO NOT mix radial and non-radial tires. All four must be either radial or non-radial.
DO NOT mix tread pattern types such as all-terrain and all-season.
Winter/Snow tires – It is always preferable to apply winter/snow tires to all wheel positions, including duals, to maintain vehicle mobility and control.

Tires and Tubes Affected By Flood Waters

The Mickey Thompson Tires and Wheels Company recommend the following with the respect to tires and inner tubes that have been exposed to flood waters. Flood water contains contaminants such as oil, grease, salt and other contaminants which can be damaging to tires and tubes. This recommendation applies to all types of tires including passenger, light truck, truck, off-the-road and agricultural tires:

Tires that are currently mounted on vehicles that have been exposed to flood water should be cleaned and inspected for physical damage such as cuts, tear holes, or scrapes which might allow contaminants into the tire. Tires should be cleaned using a mild vegetable based soap and non- pressurized clean water. A pressure washer should never be used to clean tires. If the tire damage is present, the tires should be discarded. If no physical damage is found, the tires may be returned to service. Due to the likelihood of damage to the inner structure of a tire by contaminants, un-mounted tires that have been immersed in flood water should be discarded. All other un-mounted tires should be inspected for debris damage by a qualified tire professional before being placed in service. Inner tubes that have been exposed to flood waters should also be discarded.

Understanding DOT Tire Inflation Pressures

TIRE SIDEWALL INFORMATION

Federal regulations mandate that tire manufactures place permanent information on all DOT tires showing maximum load and inflation. The inflation pressure shown is the maximum allowable under any circumstance, and necessary only to provide a safe load carrying capacity of the tire or when sustained high speeds are expected.

PROPER INFLATION PRESSURE

Again, the pressure listed on the tire sidewall is the maximum pressure and not intended as a guide for normal inflation pressure. These things are dictated by the vehicles weight and use (ie: high speed). Always start with the vehicle manufacturer’s information on inflation pressures. With modified vehicles, or vehicles using tire sizes other than OE, it is valuable to understand the weight bias of the vehicle and intended use along with the maximum load capacity and inflation.

Always use a tire with a load carrying capacity that matches or exceeds the weight carrying capacity of the OE tire. With light truck tires and applications, the load capacity is more critical than the load range when choosing non OE sizes. Due to the reduced load capacity on P-metric tires, Mickey Thompson does not recommend their use on O.E. LT tire applications.

It is also important not to check tire pressure when the tires are hot after use. Over-inflation can produce a harsh ride, makes the tires susceptible to impact damage, and promotes faster than normal tread wear along with decreased traction performance. Under-inflation (or over-loading) will cause excessive heat build up which can lead to tire failure.