Dealer Service Information Bulletin 68-I-51 – Premature Tread Wear-Out Wide Oval Tires

Early tread wear in the center rib section on Wide Oval tires can be caused by incorrect inflation pressure. The illustration (see Fig. 1 in the scan below) shows a normal tread wear pattern; the upper shaded portion depicts the wear pattern resulting from over-inflation.

It is recommended that Wide Oval tires be maintained at 24 PSI* for both front and rear wheels to minimize the possibility of early wear. Higher inflation will tend to abnormally distort the tire contact surface and cause the center ribs to assume a disproportionate share of the work.

Inflations above 24 PSI should only be used when the vehicle is driven with “full-rated” loads, as described in the Owner’s Manual.

*Always check tire pressure when tires are cold.

This is a transcription of the original dealer bulletin for easier reading and search. The complete original scan, including the figures, is shown below.