thallium

I used to work at a tire shop and at first glance that looks like it was driven on very low air for some time, like nearly flat for a number of miles. Proper air pressure allows the heat to dissipate. When driven on very low air for long enough the sidewalls get very hot and degrades the rubber which eventually breaks down. What does the inside look like? If it looks similar that's what it is. If the inside is fine then it's something else grinding it but I doubt a curb unless it's really short because the rim is not severly curb rashed.

DallasJhwk

Tires were fine on the inside but Discount Tire seemed to agree that the damage was caused by under inflation. I replace all the tires.

Took the car to a mechanic for brakes and pointed out the rubber buildup and he told me that it's not rubber but rather plastic buildup from the air dam bottoming out. Now I need to figure out why the right side is bottoming out with no leakage from the strut.

It also needs new control arms (bushings are cracking).

Thanks to everyone for weighing in on possible problems/solutions.

thallium

That's what it looked like to me but I'm surprised that the inside did not look similar. Did the driver remember a situation where they might have driven it for a number of miles at a good clip with very low air?

DallasJhwk

The 21 year old driver is my daughter who uses the car to commute to school. I can confirm that I found the tire with only about 20 lbs in it a few months ago. The car doesn't have TPMS unfortunately and I need to do a better job of staying on top of the condition of both her car as well as that of my wife.

thallium

I just realized we might not be talking about the same thing. When I said, what does the inside look like, I meant the opposite sidewall but realized you might have thought I meant the interior of the tire. For what it's worth, if the tire has run long enought, hot enough the rubber on the interior of the tire will degrade too and when you dismount the tire there will be a lot of fine rubber granules and and a similar groove there as well.

DallasJhwk

I assumed that you meant the outside of the tire facing inboard and can confirm that the inboard of the exterior was in good shape. The tire guy theorized that turning more in one direction (right) can put uneven stresses on a tire that's compromised by under inflation.

sbagdon

I can see that a less-expensive tire would have a weaker sidewall, that would be more sensitive to fluctuations in tire pressure... and that a more-expensive tire would have stronger sidewalls, permitting more fluctuations in tire pressure. It also is probably related to comfort... strong firewall, more tolerance, less comfort... weaker firewall, less tolerance, more comfort.

The sidewalls in the pics just don't appear very strong.