Tires

Ralph-

The decision to remove a tire from service is dependent upon a number of factors and each fleet/operator will weigh these criteria differently depending upon their own preferences and policies. Some of these factors include wheel position, type of service, tire condition, truck maintenance, and willingness to retread.

Looking at wheel position, your 8/32 rule is a common guideline for steer tires. If you manage your tires for retreading, pulling your steer tire with more non-skid enhances casing life enabling a new life as a drive or trail tire. Driver satisfaction and truck responsiveness are other common reasons to pull steer tires at 8/32 or higher. On the other hand, fleets who do not favor retreading, or have high miles/32 requirements, will commonly run a steer tire out to 5/32-6/32 given an even wear pattern. A quality steer tire like the G395 LHS will have excellent wear patterns enabling longer run out before pulling the tire. In the drive position, even wearing tires often run to 4/32 before being pulled from service. Similarly trail tires are often run out to 2/32 before removal.

Various service applications will place different demands on the tire affecting the recommended amount of non-skid at removal. For example, a truck running a regional route may keep a tire in service longer than a line haul truck who puts more demand on the tire and is farther from service locations. Also, poor truck maintenance can result in a 12/32 tread for the majority of the tire, but have an outside shoulder with less than 8/32 thus requiring removal.

A good resource for best practices is the "Recommended Maintenance Practice Manual" put out by the American Trucking Associations. http://tmc.truckline.com

Thanks for the question Ralph