Rotating tires is necessary to balance wear

Hey there, time traveller!
This article was published 23/09/2005 (7489 days ago), so information in it may no longer be current.

QUESTION — I have a question regarding tire rotation. I replaced BF Goodrich tires (worn out) with Good Year Allegro tires at Canadian Tire (CTC). I went in for the 10,000 mile free rotation the other day and gave them a diagram of rotation from the car manual – RF to RR, RR to LF, LF to LR, LR to RF – simple enough. They said this was wrong, and went front to back, back to front on each side — no crossover. I asked the service manager later and he said this is done on the first rotation (10,000) only and any subsequent rotations would be as per the car manual. Probably no harm done but I have never heard of this procedure before, have you?

A. Tire rotation always brings up some controversy. The objective of rotating the tires is to balance the wear so that all the tires wear evenly. Some rotational patterns even include the spare tire (if it is a full size spare) so it will wear the same as the other tires. I recommend against this though unless you rotate tires often, because placing two different size tires on the drive axle can cause differential gear wear.

The tire rotation shown in your manual would be fine at any time, but sometimes it can also cause a problem. Occasionally, a tire will take a “set” and cause a pull to one side or the other. I have swapped many tires that caused a slight pull in the steering. It seems as if the tire was constructed with the inner cord materials at slightly the wrong angle. Usually, it is a cheaper tire that has developed this problem. Most do not. The tire may be fine when new, but after it has worn some and gone through many heat cycles, it tends to cause a pull in the steering. If this tire is placed on the rear axle of the vehicle, the pull is hardly noticeable. If it is on the steering axle, then the pull can be objectionable.

Many technicians will rotate the tires front to rear on both sides, to prevent a tire pull the opposite way. Sometimes a wheel alignment technician will adjust the alignment angles to compensate for a slight tire pull and if the tires are rotated side to side, the problem becomes very noticeable, requiring either new tires or another alignment. The simple way to reduce this possibility is to keep the tires on the same side of the vehicle.

There is nothing wrong with the way the tires were rotated on your vehicle, but I am unaware of this being a requirement of first rotations only! Rotate them with either pattern, but do rotate them regularly for best tire wear.

Q. I have a 1999 Safari All Wheel Drive, 170000 km. In June 2003 I had new pads and rotors installed (life-time pads and rotors). In April 2004, April 2005, and July 2005 I had the rotors replaced because they were out of round (feels like pulsing of brakes). It is now two months since they were last replaced and I can feel the pulsing returning. I have been told by the installer that going though puddles when the brakes are hot, and hard braking, warps the rotors. Puddles I cannot help but I do not hard brake. This problem started with the new lifetime pads installed in 2003. I have suggested that the pads are too hard and are over heating the rotors and warping them. I have to go back to get the rotors replaced by warranty. Any ideas?

A. Hard braking that overheats the rotors can warp them, as can suddenly cooling them after they have been very hot, but if driving through puddles would warp rotors under normal driving, then every vehicle on the road would have warped rotors. I suggest there is something wrong with the rotors or installation.

Have the technician measure rotor lateral runnout after the new rotors are installed. The maximum runnout for your vehicle should be .003 inches. If it is more, then even though the rotor braking surfaces are parallel, they will wear unevenly, causing brake pulsation. Excessive rotor runnout could be caused by a poorly machined rotor, a bent spindle or dirt between the rotor and the mounting hub (on free rotors only). Clean everything thoroughly and measure again. The rotor may need to be machined using an on-vehicle brake lathe to eliminate runnout.This should correct your brake warping problems.