i have noticed flat spot and it takes a while to warm up, is that normal with the Perellis

 

I moved my pressure from 35-40 on my 2008 F-150KR. It made a huge difference in the flat spots. It used to ride rough until it warmed up, now it rides well from a cold start.

 

I just use the factory recommended 40 psi settings and have had no problems whatsoever.

My guess is, with all the negative publicity surrounding some of the defective tires in the last 10 years, they're pretty serious about the recommended pressures.

- Jack