A guess indeed...for comparison, I am mounting a non-run flat (Falken 612) to compare to my run flat (Kumho Ecsta SPT). Of course, I'm not sure how scientific that comparison will be since they are two different brands of tire. If it performs any better than my Kumho, I will be ecstatic. As a starting point, I will be running about 10 more psi in this new tire.