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SLOW DOWN AND ROTATE

Posted: August 1, 2014 by Jim Park

There’s more to keeping your tires fat and happy than just thumping them with a stick from time to time. In fact, proper inflation is only part of the strategy. Keeping the tires running true and wearing evenly might mean two or perhaps three rotations over the life of the tires. Sure, that means a little extra work, and a few dollars out of pocket, but the payoff could be substantial.

Take this guy, for example. The February 2004 ‘Roundup’ section in highwaySTAR featured a short piece on Jerry Wallage, an owner-operator based in Cambridge, Ont. who rolled a whopping one million km on a set of drive tires [“A Million Clicks on a Set of Drives”]. His claim to fame is regular tire rotation.

Wallage is pretty easy on the brakes and the throttle too, he says, which certainly contributes to making tires grow old gracefully, but rotating them at the appropriate time can wring out tread mileage never before imagined.On tandem drive axles, the tires on the rear axle will wear faster than the tires on the forward one. To even out tire wear on all eight drive tires, extend tire mileage, and prevent having to replace your rear tires well before your
forward drive tires are ready for removal, it makes sense to rotate the rear drive tires to the forward axle and vice versa.

Many people use an X pattern for rotation and move the left rears to the right forward drive position and the right rears to the left forward position.

Since tire wear rates and wear uniformity also vary with wheel position, you may want to put the inside tires on the outside and the outside tires on the inside too. This rotation should be done when the difference in tread depth
between the forward and rear drive tires is between 3 and 4/32nds.

Rotating tires at this point will also prevent excessive slip, loss of traction, and differential strain due to mismatched tire diameters between the axles. That means less wear and tear on the driveline.

On the steer axle, right front tires wear more slowly than the left fronts, but are more susceptible to irregular wear conditions that can necessitate early removal. To extend steer tire life, watch them closely. Should you see a
difference of 3/32nds between them or an irregular wear pattern beginning to develop, rotate them left to right. Steer tires that have developed truly ugly irregular wear patterns should be rotated to the drive or trailer axles to use the last remaining 32nds of tread depth there. And check your alignment while you’re at it – the likely culprit in accelerated and/or uneven wear.

One of the first tire maintenance policies that may deserve re-examining is when to remove a tire from a vehicle. Regulated standards here and in the U.S. require that tires on steer axles have a minimum of 4/32nds of tread, and all other tires must have 2/32nds. However, in order to improve
retreadability, consider removing tires at 4, 5, or even 6/32nds. Sacrificing a few 32nds of tread for higher casing value is a trade-off worth considering.

And finally, when it comes to repairing damaged tires, don’t be quite so willing to scrap a tire with a few nail holes or more than one section repair. Radial tires can have a maximum of three section repairs provided the repairs are made properly and the repair units do not overlap.

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