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About Barry Smith
Expertise
I have over 30 years experience in the design, manufacturing, and testing of tires. I have served as the technical advisor to the "800" number. I have authored or co-authored many publications - usually without credit. I can answer almost any technical question, but please don`t ask me to compare brands. I probably have prejudices because of my work experience.

Experience
Member SAE (Society of Automotive Engineers) Member Tire Society (Tire Technical Organization) SCCA Regional Competiton License holder Authored many training manuals on tires, their care and use.

You are here: Experts > Autos > Auto Parts > Tires > Cupping Problem

Tires - Cupping Problem

Expert: Barry Smith - 11/5/2009

Question
I have a 2008 Toyota Sienna LE mini van. I rotate tires every 5,000 miles. At each rotation, no irregular wear was detected. After the 20,000 mile rotation, the tires began making a cupping sound. I first took the van to a Toyota dealer and was informed it needed alignment and balance. Next, I went to an independent repair facility for a second opinion; they found the alignment, balance, and road force were within specifications. I then went to another Toyata dealer for an alignment check; I have their print out that also shows the van is not out of alignment. What must be done to fix the cupping problem?

Answer
Bob,

I am of the opinion that published alignment tolerances - not the target value, but the allowable deviation from the target value - are too wide by half.

So even though a vehicle is "In Spec", I don't think it means the vehicle is "OK". Look closely at the toe and perhaps the camber. I think you'll find that the values are not within the inner half of the spec.

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