I Let The Air Out

Maybe lower pressures are easier on the suspension? Would seem logical. FWIW, I'm setting ours at 42/40psi front/back. Doing that with the 195/65-15 snows through the winter seemed more forgiving than on the OEM's, which are 215/45-17.

 

Sorry about your dad.

I am confused though. What make of tire and car is overinflated at 30 psi?

 

At manufacturer specific psi, I feel like I'm riding on marshmallows! Anything less than 44 psi doesn't inspire confidence in handling. I run mine at 52/50. No uneven tire wear, the car glides better and handling is tighter.

 

If you refer back to post # 15, the tire was an 8" tire. Thus, it was not a car tire. It was actually a tire from a portable generator. My point is that even at 30 pounds per square inch on something so small doesn't seem dangerous, but can become very lethal very quickly. A few inches above or a few inches below where my dad was hit and he would have either been blind or his jugular would have been cut.

Then look at a much bigger tire inflated at 50 psi and also over the maximum recommended pressure and you can imagine the potential for lethal danger if something were to go wrong.

 

Exactly! At 35 psi, POWER mode feels like ECO mode. The car won't move. I may bump up from 42/40 to something more.

 

Tires WILL explode if over inflated. Coming from someone who maintains tires and tubes in aviation I can vouch for that. Not sure of the exact makeup of the Prius tire, but in aviation the general rule of thumb is max sidewall pressure +/- 5%. Obviously burst pressure depends on how many chord plies there are, and the structural makeup of the tire itself (steel belted, rubber quality, etc).. I have toyed around with the idea of upping my sidewall pressure as I have read about on here, but with only 2200 miles on the car I think I am going to give it some more time before deciding on that.. Certaintly a lot of factors to consider when you think about all the stress you put on the tire by over inflating it, the way you drive, road conditions, and the reduction in traction with the smaller contact patch (not to mention these are already tires designed to have low rolling resistance/traction).

 

If I were landing my Prius, I'd go max sidewall +/- 5%. Sounds about right.

For a hypermiler, there is considerable cushion on the upside, though I don't go much past 5% over myself.

Now placard is way below sidewall -5%, and the shortened tire life and reduced mileage and handling are the results.

Thus, overinflated means above max sidewall. Underinflated means below max sidewall. The technical term for psi below placard is "darn near flat."

 

And the 8" tire would be a flotation tire probably spec'd for about 10-12 psi, so 30 psi is way over the top.

 

:d:d:d

 

My dealer leave my pressure alown. He writes down 42 / 40

 

I inlfate all 4 tires to Max sidewall pressure
as marked on the tire sidewall, 44 PSI.

Tire are Michelin Energy Saver, 195X65X15. Over 38,000
miles on them and looks like another 30,000 miles left.

MPG did increase 2-3 mpg's over the stock Yoko Avid tires.

Your tires will probably last longer, tread life, with max pressure
as well as get better fuel economy.

just my opinion.

al