Air Pressure in Tires

Mixed tires are difficult. I would say start with 95% of tires' sidewall max in the front, and 90% of same in the rear. If you want to take up the habit of measuring tread depths, you could see if this gives you a good balance of edge vs. center tread wear, and adjust up/down accordingly.

Stay with side to side tire rotations to keep the like tires together. Your regular load tires could spend some time in the front, but preferably not if you are driving fully loaded, high speed, in the summer.

No advice on dash rattles, other than louder music. Them are often tricky to find and cure.

 

<div class='quotetop'>QUOTE(Alexstarfire @ May 26 2007, 11:01 AM) [snapback]450412[/snapback]</div>

you need to go by what it says on your door jam and the same thing will be in your owners manual. those max pressures are for if you have your car loaded to max wieght capacity. having them over inflated will were the center of your tires out in a hurry.

 

jimgrames62, I gotta tell you, tire inflation is a topic that has come up for Prius at least since 2001. The world includes folks who stick with the door jamb numbers, and those who go higher. The former group have faster tread edge wear, with perhaps a few exceptions. The latter group has not yet reported excessive center tread wear. Ever.

Please understand that if high pressures did this I would be among the first to notice. And to speak out against the practice! I have been measuring tread wear with micrometers on my Prius for 106k miles, with 3 sets of tires so far. Much nerdly data that I would be happy to transmit.

But first things first: safety. Prius tire blowouts have happened, but those to folks who air to the low side. Tires with too much sidewall flex can overheat and fail.

Traction is a very important question! So far, nobody has set up an S-course with orange cones at a Prius meeting, so that we could see where the best is. I hope that conversations like this will cause that to happen. In the meantime, I continue to believe that even (center vs. edge) tread wear is consistent with the best traction that can be achieved. That even wear will simply not happen at Prius-recommended 35/33 pressures, with any tires I have yet seen.

The 'center wear at high pressures' doctrine (that I read so often) appears to be a relic from the days of bias-ply tires. Please, at your convenience, examine the construction of radial-ply tires, and decide for yourself if it seems physically possible that they could bulge up in the center at any inflation pressure. Steel or polyester belts will not stretch.

Not suggesting 90 psi of course. Up there somewhere, either the bead will fail, or the wheel itself could, and nobody wants that. But whatever it says on the tire sidewall is a good starting point for best psi. Let's work down from there.

 

48 lbs air pressure in each tire
I was putting air in our bikes and while I was at it I thought that I would check the pressure on my 2 week old 2018 Prius Prime. All 4 tires were 48 lbs! 4 lbs over the maximum pressure per the side wall.

So much for dealer prep. I'm guessing that the car gets shipped here with that much pressure, to be adjusted by the dealer. I have never checked the pressure this soon on a new car glad I checked...

 

They might have missed other things. There's a couple of oblong shaped plugs typically needing to be installed on the underside, for one. They're about 2" by 1", fill holes in reinforced plate, maybe used for some sort of locking pins during shipping?

Let the service manager know, maybe you'll get something complementary. They should actually redo the the prep; you paid for it: but maybe let sleeping dogs lie. Ask him what he thinks.

 

Thanks Mendel,

Now that you mention this the windshield washer tank was not filled and my wife noticed this when we were picking up the car - Thanks

 

Should have mentioned: the plug locations (if similar to 3rd gen) are just a little inboard of the rear scissor jack locations. Heavy plate in the area.

 

Thanks, Let's hope I don't need to know. I had a 2 year lease on a 2002 Mercury Marquis and that car had 3 flat tires during the 2 year lease ! It wasn't the car's fault. AFAIK I had one other flat since then on my 2008 RAV4. I can't imagine having to have the car towed some place because of a flat! BTY I've changed all of my own flats... OK, a kind soul helped me with the RAV 4 .

 

Does rav 4 have the spare under hatch floor? I think so? What I don't like is spare hanging under the car. Pilot is like that, a real handful.

 

Starting with my first Prius in 2009, I've checked each new car's tires immediately, with intent of raising pressure somewhat from the door label. That first Prius was at 39-40 all around, and numerous other readers here found the same. Yes, it was the factory pressure for the Pacific cruise, intended to be reduced to the label pressure as part of PDI.

Starting with Gen4 (I don't recall if it was just Prime, or the others too), we started hearing reports of 50-ish psi at delivery.

 

The 2008 RAV 4 had a full size spare off of the back door.

"Yes, it was the factory pressure for the Pacific cruise, intended to be reduced to the label pressure as part of PDI."
Thanks, that confirms what I thought. The full size spare provided by the dealer had the correct 36 lb. pressure,
indicating that the dealer probably did not put air in the 48 lb. tires. I think 48 lbs. is a big deal, given that the maximum
pressure stated on the side wall is 44lbs.