there is no consensus here. Some swear by adding 10+ psi upwards of 45PSI. Others say 40. I like to erro ont he side of caution, I have to beleive that 45PSI is casuing less tire to contact the road and thus I feel it is unsafe. I run 3-4PSI over to allow for some natural loss of pressure and minimal loss of contact with road. There is a reaosn the car maker sates a certain PSI. Regardless of the "slightly harder ride" which they could compensate for in suspension they spec 32 for a reason, if the MPG benefit were that great with no loss in saftey I am sure when gas was $3 a gallon they woudl spec 40PSI or 45PSI. I read and article a while back where they interviewed a Michelin engineer who said use the MFR number, but in general it is better to be 3 over than 5 under. Why did he only mention 3? beats me, but if it were that safe to be 5 or 10 over I am sure he woudl not have compared 3 over to 5 under! We all take responsibility for our actions, I have decdied I will be responsible for me and my passenagers at 3-4 over, I won't risk hydropaning or a smaller contact patch for 1-3 MPG. If my life were worth the extra MPG I would sacrific comfort over saftey and get a Prius first and get 8-10 better MPG.

OK I stepped off my soap box...