Interpretation ID: nht80-1.45

DATE: 04/03/80

FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA

TO: Dick Pilch

TITLE: FMVSS INTEPRETATION

TEXT: This is in response to your February 7, 1980 letter to the Department of Transportation, in which you complained about the failure of a tire on your truck. Specifically, you stated that the tires on the front axle of your truck were overloaded by 570 pounds each, and that no non-radial tire is currently manufactured which would not have been overloaded if used on this front axle.

If the tires which were overloaded came as original equipment on the truck, the manufacturer of the truck violated Federal Motor Vehicle Safety Standard No. 120 (49 CFR 571.120). Paragraph S5.1.2 of Standard No. 120 requires the sum of the maximum load ratings of the tires fitted to any axle to be at least equal to the gross axle weight rating of that particular axle. This requirement is applicable to all trucks manufactured on or after September 1, 1976. If your truck was manufactured after that date, please send me the name of the manufacturer as well as the information provided by the manufacturer specifying the appropriate tire sizes to be used on the truck. The information concerning appropriate tire sizes will appear on a label on the door latch post on the driver's side of the truck. If the manufacturer has violated Standard No. 120, appropriate steps will be taken by the agency.

You also stated that certain radial tires would have met the load-carrying requirements for your truck, but that you would not use radial tires because of erratic wear patterns. For your information, I have enclosed a booklet published by the Rubber Manufacturers Association setting forth information on the care and service of radial and non-radial truck tires. On page 11 of this booklet there is a description of the irregular wear to which you refer, as well as instructions on how to prevent the irregular wear from lessening the overall mileage the tire will give you. Hence, if you wish to use radial tires on your truck, there is no reason to expect them to perform unsatisfactorily.

More significant, however, is the misunderstanding you have in suggesting that no bias ply tire is manufactured which would not have been overloaded on your truck. Such a tire is now manufactured and has been manufactured for at least the past 20 years. On page 30 of the enclosed booklet, you will find a table showing the load-carrying capacity of bias ply tire sizes mounted on 15 degrees drop center rims. The tire size mounted on your truck, the 11-22.5, does indeed have a maximum load of 5,430 pounds if it is a load range F tire. However, a load range G tire of that same size has a maximum load of 6,040 pounds, and would not be overloaded if used on your truck. This is the tire you should probably use on the front axle.

I am sorry to hear of your accident and hope that you have recovered from your injuries. Your complaint about the failure of the Uniroyal Delta tire has been recorded, and the agency will be alert to other indications of problems with this tire. To date, however, we do not have sufficient data indicating a safety problem to open a formal investigation.

I want to thank you for taking the time to express your concern about motor vehicle safety. It is only through the efforts of concerned citizens such as yourself that we can ensure maximum safety for all users of the highway. If you have any further questions or concerns about this matter or any other aspect of highway safety, please do not hesitate to contact me.

SINCERELY,

February 7, 1980

TO WHOM IT MAY CONCERN:

It is unfortunate when corporations become so large that they influence our Courts and brainwash the general public through advertising and news media.

Case in Point:

An individual purchased two tires to replace those that were wearing out. He bought bias ply tires in preference to radial tires because eratic wear patterns are standard for radial tires on a free turning wheel on all makes and this hasn't been corrected to this date. The last set was on the vehicle for 85,000 miles and was in good enough condition to put on the rear of the truck. Some 30,000 miles later, after 1-1 1/2 hours driving time on a cool morning, the temperature being 60 degrees or less and raining lightly, the tire blew out with no warning, causing the vehicle to go off the road over an embankment. The vehicle came to rest turned almost over on its side and spilling the load off the vehicle. This destroyed the truck and trailer and injured the operator. The driver was unaware of the injury at the time of the accident. The symptons became apparent about three months later, which rendered him almost crippled for many months. To this day the driver is still in pain, sometimes quite severe.

Getting back to our "Great Society" (as the joke is sometimes put), we are supposed to look out for the people that use the products that these careless giants put on the market, which are a danger to life, limb and property. There is also the danger of one of these tires blowing out on a six-lane freeway, such as that in Los Angeles, where one driving during the traffic rush about 3 p.m., could kill several people. However, those companies can continue to manufacture defective equipment by the thousands and sell it to the people. It appears as though nothing better can be had.

Example: Our federal and state governments have passed laws that a large truck can gross 80,000 pounds if it is equipped with five axles and the proper length. Front axle 12,000 pounds Tandem driver axle 34,000 pounds Tandem trailer axle 34,000 pounds

Let's look closer at the manufacturer's specifications.

A single tire, 5,430 pounds at 85 pound psi X 2 = 10,860

From 12,000 pounds - 1,140 for both For a single tire = 570 pounds overload.

Does the manufacturer say anything? No. They appear to be unconcerned as long as they can sell tires.

Let's continue. Concerning the manufacturers and their specifications, they say on dual tires, one should run 75 pounds psi and be able to carry 5,060 pounds on each tire. Let's compare the weight difference.

State and Federal Manufacturer 85 psi 12,000 pounds - single steer axle 5,430 X 2 = 10,860 pounds 6, 050 X 8 = 48, 75 psi 34,000 " - dual tandem axle 400 " 34,000 "- dual 6,050 X 8 = 48,400 " 80,000 pounds 107,660 pounds

Let's take a closer look for safety's sake. Or does safety go out the window when you are talking about a multi-million dollar corporation? It seems to apply only to the poor, dumb truck driver, doesn't it?

Look at 34,000 pounds divided by 8 = 4,250 pounds maximum weight. The safety margin is good, to say the least.

12,000 pounds divided by 2 = 6,000 pounds. Woops! Where did the safety margin go? Now doesn't this make a lot of sense? Run dual wheels on driver axle or trailer axle and you have 1,750 pounds to play with. If one tire should let go, you could in no way lose control of the rig. However, on the steer axle, you have no safe margin, As a matter of fact, you are exceeding specifications all the time. Most trucks are carrying approximately 10,000 or 11,000 pounds on the front axle at all times. Also, there isn't a tire manufactured that has the specifications that it should have as far as safety goes. There is a radial tire that will carry the 6,000 pounds, so they say. However, the manufacturer will state that on two free rolling wheels, you will have eratic wear patterns. As yet there isn't a tire manufactured that doesn't have them.

There are two ways to remedy the problem. Let's either change the load limits to compare with what the manufacturer says, or make the manufacturer (which we know won't happen) make a tire that has the rating needed to put the same percent of safety on the steer axle that there is on the dual driver or trailer axles. The third way to remedy the problem and the one most likely of the three, is to place this letter in the round file, commonly known as the "trash can".

Yours truly,

Dick Pilch

P.S. Also, we could make the same true for tire manufacturers and make them totally responsible for their products, pull them out of production when found bad and let them suffer the loss of what the user does in terms of injury, income and life.

TO:

UNIROYAL - Detroit, Michigan KIRO TV - Seattle, Washington

KING TV - Seattle, Washington

KONG TV - Seattle, Washington

20/20 - Seattle, Washington

Senator Jackson - Washington, D.C.

Senator Magnuson - Washington, D. C.

U.S. Department of Transportation - Washington, D.C.

U.S. Department of Transportation - Seattle, Washington

Office of Chief Counsel - Washington, D.C. Federal Highway Administration

National Highway Safety Administration - Washington, D.C.

Center for Study

c/o Ralph Nader - Washington, D.C.

Judge William Goodloe (Superior Court) Seattle, Washington

Over Drive Magazine

Robert Peterson

c/o Mother Trucker Magazine - Los Angeles, California

DEPARTMENT OF TRANSPORTATION NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION VEHICLE OWNER'S QUESTIONNAIRE

Pleading Omitted. Vehicle code provisions omitted.