The right tire pressure on 17" Rims

Not 215/45R17? What tires?

Ours are Michelin Pilot HX MXM4 (whew), I've settled on 36 psi all 'round. Still pretty firm, turns you into a bobble head on every speed bump.

Lifetime average currently is 4.9 litre per 100 km (48 mpg US)

I wouldn't buy them again though: ours day GreenX, but the new ones don't??

Might go with Primacy MXM4.

 

The more psi (up to max rating on the tire), the better for mpg, but you have to balance that with ride quality. At higher psi, you might begin losing your fillings due to the harsh ride. In fact, I had to trade my 2013 Persona with OEM 17's due to the overly harsh ride, even at moderate psi. Now, I'm happy to report that the Gen 4 Touring models are much more pleasurable on their OEM 17's.

 

I doubt you'll lose mpg with higher pressures, but I think the improvements are a bit overblown. Especially with lower orofile 17's, the ride gets really harsh, the higher you go. I've gone down to 32, and up to 40: the first few pounds of raise is most significant, from there on up I saw little improvement.

 

I never saw the point of making the already harsh ride of 17's even harsher still by hiking the tire pressures. Did that for almost a year. OEM tires lasted to only 30K miles. Backed them back down to 35/36 psi and enjoyed a better driving experience. Mileage isn't everything.

 

Keep in mind too: if the ride is really jarring, it's might be reducing the lifespan of shocks and wheel bearings.

 

I personally set the right tire pressure to be the same as the left tire pressure...

 

This is smart. To not do that would wear out one side of the car more, and the the other side of the car less. You want to wear out both sides, less, like you are doing.

I also use a very custom gaseous mix of 78% nitrogen, 21% oxygen and 1% argon and other trace elements. I know I'm right, but the tire dealers tell me that 100% nitrogen is a much better choice for the $10 they want to charge me.

 

Yeah, and why should I need to rotate tires: they get plenty of that, every time I drive!