Greetings,
I had my Mustang parked for 2-3 months in the garage and recently noticed the rear passenger tire was flat. (Tires are about about 8 months old with only 300 miles on them) The other 3 lost about 8 Psi each. Re-inflated the flat tire and 10 days later it lost 12 PSi. Took it in for repair, they removed tire from vehicle and put in water and they can find no leaks, not even around the valve. When I first drove it the tires definitely had flat spots for sitting so long, but this resolved after driving a few miles.

Anybody experience this before or have any suggestions?
Last thing I need is to constantly worry about flat tires.
Here's the details on Tire/wheel combo.
Continental ExtremeContact DWS 06
Front: 255/45ZR18
Rear: 275/40ZR18
Shelby Razor Wheels

Thanks for any help
LJS

 

Hairline crack in the rim?

 

Submerge the entire tire and rim in a tub of water. That's the best way to find it.