Interpretation ID: nht76-1.28

DATE: 08/06/76

FROM: AUTHOR UNAVAILABLE; R. L. Carter; NHTSA

TO: Hon. John J. LaFalce - H.O.R.

TITLE: FMVSS INTERPRETATION

TEXT: This is in reply to your correspondence on behalf of Mr. George J. Ciancio, concerning the tires on his 1975 Dodge Van B-100. Prior to responding, this office contacted Mr. Ciancio for additional information.

From the correspondence you submitted to this Administration, Mr. Ciancio did not appear to receive satisfactory responses to the questions he submitted to the Chrysler Corporation concerning the tire problems he was experiencing. We offer the following responses for his consideration:

Question 1 - Stamped on the sidewalls of the original tire the rating is 1400 pounds. Is this maximum load?

Response - Yes. The maximum load rating for an E7815 B passenger car type tire is 1400 pounds. This rating is only applicable when this tire is used for passenger car service. For a van of the type used by Mr. Ciancio, a service factor is applied for "truck service" and the maximum load becomes 1270 pounds.

Question 2 - My registration shows the van weight at 4434 pounds. What is the laden weight of the B-100 van?

Response - Mr. Ciancio was contacted on this point. Our data indicates that the Dodge B-100 van should weigh approximately 3600 pounds depending on the installed equipment. As the Gross Vehicle Weight Rating (GVWR) is 4600 pounds, the approximate laden weight would be about 1000 pounds as indicated by Chrysler. If in fact, the van does weigh 4434 pounds empty, then the laden weight cannot be over 166 pounds, which of course, cannot be correct.

Question 3 - Do I read correctly that my total tire weight allows 5400 pounds, which includes van and load?

Response - No. From page 3 of your Owners Manual, you will note, "The GVW rating of your truck as manufactured is shown on the Safety Certification Label. The GVW rating is the total permissible weight of your truck including driver, passengers, body, and payload." As the GVWR of the B-100 van is 4600 pounds, 4600 pounds is the maximum load.

Question 4 - The axle capacity in the manual front and rear is shown as 2700 pounds. Does this mean with loaded weight?

Response - No. The axle capacity of 2700 pounds is the rating determined by the vehicle manufacturer as the maximum load that should be applied to that individual axle - it does not mean that both axles can take the design capacity for a total of 5400 pounds. Again, the B-100 van is limited to 4600 pounds GVW. Vehicle load on each axle is further limited by the suspension's spring and wheel ratings which reduce actual load carrying capacity to GAWR valves of 2480 front and 2340 rear. These figures indicate the importance of proper load distribution in the vehicle.

Question 5 - Is it true if I increase my tire size from E78-15B to G78-15B, would it make any difference in the load I could carry without jeopardizing the axle weight capacity?

Response - No. By changing the tires on the van from E ratings to G ratings would not change the GVWR of 4600 pounds. The van is still limited to a GVWR of 4600 pounds.

We hope that the responses to these questions will answer some of the concerns of Mr. Ciancio.