How much tire air pressure is still safe?

[monroe74]

"all tires on foreign-built cars are inflated to 65 psi at the factory"

This is from a Honda service bulletin (2/06): "New vehicles get shipped from the factory with tire pressures set from 40 to 45 psi. This is intentionally done to prevent flat spots from forming during the long haul."

[1993CivicVX]

Originally Posted by EH3

sidewall says 35. there you go.


100psi is just absurd unless it's a loaded semi or something. inflate to the max psi on the sidewall and you'll never have to worry. the difference in FE above that is probably not even measureable.

Of course it is. I go 44mph at 60psi coasting down my hill, and about 40mph at 45PSI

[VXer]

So, if the car's manual recommends 32 psi (for tires with max 35 psi), but you change your tires for ones with max 44 psi, I'm assuming you should ignore the recommendation. Why wouldn't the car manufacturer just say "fill to 3 psi below max sidewall"?

[CaliberMan71]

My 07 Dodge Caliber has FireStone tires on it and it has max psi on side wall is @44psi, I try to keep 40 psi in them.

[theholycow]

Originally Posted by VXer

So, if the car's manual recommends 32 psi (for tires with max 35 psi), but you change your tires for ones with max 44 psi, I'm assuming you should ignore the recommendation. Why wouldn't the car manufacturer just say "fill to 3 psi below max sidewall"?

The car manufacturer calculates the minimum pressure to provide a safe ride with the original equipment tires when they're brand new. They do this to provide a soft ride when you test drive the car.

Don't forget, just because our first interest here is FE, that doesn't mean the rest of the world feels the same way.

[slurp812]

Originally Posted by molinee

Do you really think that this is true? Mileage would be no better at 45 psi than it would at 35 psi? How is this possible.... Just wondering.

I disagree, I can FEEL the car go easier, and coast further with more pressure in the tires. There has to be a balance tho. Traction, and safety must be considered. I have yet to run anything over 42 psi. 100 psi is just nutz, I do agree with that...

[slurp812]

Originally Posted by VXer

So, if the car's manual recommends 32 psi (for tires with max 35 psi), but you change your tires for ones with max 44 psi, I'm assuming you should ignore the recommendation. Why wouldn't the car manufacturer just say "fill to 3 psi below max sidewall"?

Because they cant predict what tires will be available in the future...