Originally Posted by SVOboy
My friend put 50+ (gauge went to 50) in his tires on his civic and I beat the hell out of it and the steering was fine. Normal understeer of course but we did some crazy drifting in that bucket. You should be plenty fine at 50. I think dan's tire limit is 35 and he's at 50.
The Prius has 44 MAX rated tires but I have had them at 50PSI for about 60k miles with no problems. I had them at 60psi for another 3k but the ride was a little bumpy. This subject has been discussed at some length and like SVOboy said, no one has ever been able to provide me with evidence that any tire has blown after being inflated to 50PSI. According to someone whom I would consider an expert, auto tires are designed with a minimum 120psi explosion rating. Truck tires are designed for 300-400 PSI.
I am not going to recommend that anyone do anything. Just providing data. Remember that there are hundreds of Insight drivers with 50+ in thier 44max rated tires. Again, I have never heard of a failure. What is quite clear is that there is more blowout danger associated with underinflated tires than with overinflated tires.
All that being said, I doubt that you will notice much of a gain, maybe 1/2 MPG.