Delta 88 V6-3800 3.8L (1988)
Irregular/premature tire wear is aggravated by excessive toe-in (or toe-out). Excessive camber can also be a contributor, as can operating conditions,
such as city driving with a lot of cornering. Irregular tire wear usually occurs on non-drive axles, such as the front wheel positions of rear drive vehicles.
An early indication may be an increase in tire noise. In most cases, modified "X" tire rotation, which is a scheduled maintenance at 7500 miles, will
equalize tire wear (see Fig. 1). Some amount of wear is expected and should be considered normal. Only when the cross grooves in the tread disappear
within 12,000 miles should the tires be replaced under warranty (see Fig. 2). Even when these grooves disappear, however, the tire is normally only half
worn in this area. Whenever tires are replaced for this reason, alignment should be checked and reset to specification, if necessary. If tires are needed for
any of the above conditions, they should be purchased from your local tire outlet. If tires are not readily available, each tire manufacturer has a toll-free
assistance line for car and truck dealers. These numbers have been previously provided in Dealer Management Bulletin 88-1-12. The tire invoice amount
should be entered as a net item on the warranty claim. Labor code E0420, replace wheel and/or tire, should be used.
In Figure 1, the rotation pattern eventually gets each tire on all four positions. It gets those tires on the non-drive axle, which are most prone to irregular
wear, to turn in the opposite direction. This will equalize wear the quickest, and tire noise related to tread wear will actually become quieter after a few
thousand miles.
Evaluating Tire Wear - Typical All-Season Tire. (Figure 2)
Tire should be replaced only if these grooves are no longer visible within first 12,000 miles.
