Factory installed summer only tires.

[ICU812]

Test drove a Mustang and it had a thumping at 15-37 mph, like the tires were flat spotted.
The car had 6 miles of it, Dealer said it had sat for a few months over the winter and these performance tires do that.
These are not bias ply tires so I am confused.
Is this an issue with summer only tires from Pirelli?
I have had soft compound BFGkd(tm) tires before but the car never sat for any length of time on them.

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[EFI]

This can happen on almost any tire if it sits long enough, especially if the psi is on the lower side.

The good news about non bias ply modern street tires is that they usually bounce right back to their original shape after a little bit of high speed driving and the thumping goes away.

 

[Sabre]

Not unusual....especially if they sat in the same spot for a while during cold weather.

 

[Cobra Jet]

If the car is driven a few miles, the flat will go away and so should the NVH associated with it. As others have said, it's completely normal, selfishly sitting in one spot for months on end.

If you're thinking of buying, then negotiate with Dealer and ask if they will swap tires to make you feel better, or take $ off the deal.

 

[ICU812]

I am worried about what it does to the belts and rubber construction of the tire, having the steel belts taking a set like that, pulling on the rubber. The tires are 425.00 a pop to replace if the layers start coming apart. and what does it do to the speed rating and use?

 

[EFI]

I am worried about what it does to the belts and rubber construction of the tire, having the steel belts taking a set like that, pulling on the rubber. The tires are 425.00 a pop to replace if the layers start coming apart. and what does it do to the speed rating and use?

Nothing. You can certainly try to ask for a new tire, but you're most likely not going to get it.

Modern tires are much more resilient than the ones 30-40 years ago, especially if it's a good name brand like Michelin or Pirelli.

 

[ICU812]

Nothing. You can certainly try to ask for a new tire, but you're most likely not going to get it.

Modern tires are much more resilient than the ones 30-40 years ago, especially if it's a good name brand like Michelin or Pirelli.

Oh, I don't expect them to put new tires on it. Just wondered about the effect of this and high speed use.
I have had tire steel belts break at speed. and wire strands hanging out the sidewalls.
Guess if I get the car, I will have to get another set of shoes to put on it while it sits in the winter months.

 

[shogun32]

if the car is going to sit, put it up on stands.
Even my UHP all-seasons do that after a day or two of sitting in cold temps. Find something else to stress about.

It's not the belts taking a set, it's the rubber compound that takes a set.
The following tires 'flat-spot' in 'cold' weather after mere hours to 2 days
Conti DWS06
bridgestone RE980
BFG Comp2 A/S
Pirelli Nero and such 'stock' total shit 'OEM'

Mich PS4s
Goodyear SC3

 

[I Bleed Ford Blue]

Way back in 07 I had an F150 with the factory installed 20" pissrelli scorpions. They would flat spot just sitting overnight at temps below 40 degrees. Pirellis are cheap garbage tires, if you want to greatly reduce or eliminate the flat spotting, get some good tires and ditch the garbage pirellis.

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