Tires will usually handle far more pressure than the sidewall max. Plus when the tire is pumped up more, it should heat up less (most of the heat is generated from the tire deforming a little as it rolls, more pressure reduces that). I would much rather have tires filled 10PSI higher than the sidewall max than 10PSI under the recommended pressure.
I think that it is true inflation makes tires harder on the shocks/struts or whatever. but these cars often come with larger wheels and tires that also have lower profile. that extra weight and lower profile will be much harder on the suspension, than a stock 15 with 51psi IMO.
I have thought about driving around closer to the max sidewall pressure, but the roads are such a disaster and they don't get fixed properly. There are plenty of large-deep divots in the road where you could hide a rhinoceros. I can't imagine what max sidewall would do to my car, so I just feel like I need to keep my pressure closer to 40 psi. Any advice??
Been running 45 front and rear. only slightly harsher ride, slightly improved mpg. Works for me so far!
if you have harsh bumpy roads I would not max out the tire pressuer, I think you already came to a reasonable conclusion. If you have the larger 17" wheels with the lower profile tire I would switch to the 15" the taller sidewall will help a lot with those type of potholes and things like that. they just don't look as cool