Rick's Free Auto Repair Advice

Tire sidewall indentation — tire damage?

Tire sidewall indentation — something to worry about?

Tire sidewall indentation or “undulation” tire sidewall indentationis a normal result of radial tire construction. They’re formed during the manufacturing process as tire cords are wrapped around a mold. The cords wrap from one tire bead, up the sidewall, across the tread area, down the opposite sidewall, and finally to the opposite tire bead area. The cords are wrapped side-by-side and as the wrapping is finished, the final wrap overlaps the first cord. when the tire is finished, this overlap can be seen in the tire’s sidewall as a tire sidewall indentation or undulation. This is a perfectly normal visual result of tire manufacturing and is NOT a defect. It does not impact the performance of the tire.

Tire sidewall indentations are more noticeable on larger sidewalls

The indentation will be more noticeable on tires with larger sidewalls than on low profile tires. The tire sidwall indentation may also be more noticeable on tires with higher inflation pressures.

Tire sidewall indentation versus tire bulge

While tire sidewall indentation is perfectly

tire sidewall bulge

tire sidewall bulge

normal, a tire bulge is not. The tire in this image is unsafe and must be replaced.

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Posted on by Rick Muscoplat


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