Many Flat Spots on both Rear Tires

[BlackGun]

Looked at my daughters Volvo. Both rear Firestone H wall tires have flat spots all the way around. They are at a slight diagonal worn more on the inside. What causes this? Front tires are almost new and look fine. Not from sitting parked that’s for certain.

 

[rdinatal]

Shocks, out of balance (tire, rim)?

What type of rear suspension?

 

[BlackGun]

Shocks, out of balance (tire, rim)?

What type of rear suspension?

I have no idea. It’s a 2007 S40. I’ll look it up

 

[Tailhunter]

Shocks are bad.
Allowing tires to jump, creating flat spots.

 

[Beef15]

Shocks normally the first place to look.
I've seen other better references for tire wear patterns, this is just the first I came to.
https://www.knowyourparts.com/technical-resources/info/understanding-tire-wear/

 

[Schattenreiter]

Drifting.

 

[THE PUNISHER]

Shocks are bad.
Allowing tires to jump, creating flat spots.

Bingo

 

[BlackGun]

Is it possible the tire rotation was done wrong?

 

[Infamous1]

No tire rotation would not cause it. It needs a four wheel alignment and a suspension shakedown by a competent tech.