Sidewall Indentations / Undulations
Fig. A: Vertical indentation on sidewall from rim to tread.
A common byproduct of radial tire construction, sidewall indentations/undulations are more noticeable in tires with taller sidewalls or operate at higher inflation pressures. Fortunately sidewall indentations are a cosmetic condition that does not affect the performance of the tires.
Tire casings are reinforced by multiple fabric cords encased side-by-side in a thin sheet of rubber. Radial ply tires feature one or more layers of cord (depending on the tire's required strength) that run parallel to each other from bead to bead (with each individual cord running up the sidewall, across the tread and down the other sidewall). Because of their "straight across" radial orientation, the overlaps where the sidewall cords are lap-spliced may cause indentations.
When the tire is being cured, it is pressed against its metal mold. However when the tire is mounted on a wheel and inflated to operating air pressures, it is free to expand. These overlapping splices may create slight indentations since the stretching capacity of the lap-splices is slightly less than the rest of the body ply. In reality, the splices are the most reinforced area of the tire's sidewall.
Since radial tires feature steel cord reinforcing belts under their treads to keep them flat, indentations only appears on the sidewalls.
Sidewall indentations are normal, and every radial will have them to a degree. Some are more noticeable than others. That being said, an excessive sidewall indentation may be prorated by the manufacturer if necessary.I have less than 1500 miles on my new maverick. I just happen to look at the rear tire today and noticed that there’s an indent. There are no blemishes on the side of the tire. I didn’t curb anything. Are the tires under warranty I know this is unsafe.
