BTW, when you*re at the America*s Tire checking out the tire pressure for free, make sure to check your mini spare tire in the trunk too. Unlike the road tires, it should be very low! (40+ psi instead of recommended 60 psi!)
My last several cars that had donut spares have recommended the spare tire pressure to be 60 PSI. That is also the pressure that is embossed on the sidewall of the spare in my CX 5. Why would you think running at more than 30% below the recommended pressure is the thing to do ?