new car tire pressure ?

maybe they ship them like that to keep them round, and the dealer prep forgot to lower it?

 

You should be safe. I run mine at 55 psi. I had a 2012 v that I ran at 65 psi for 4 1/2 years and got 100k out of them and never had a problem. I know a lot of people on here don't like them that high, but results are results.

 

I've heard of M-B or BMW pumping the tires as high as 80 psi when they go on the ship to allow for air loss in transit, but it could also be to prevent a flat spot from forming.

 

Another possible reason for over-inflated tires is a bad tire pressure gauge. I'd double check with a different one just to be sure.

 

The placard on the door jam has the recommended cold inflation pressures, 36F/35R. The 44 on the tire is the max allowable according to the tire maker, not the recommended pressure on this car. Higher than recommended pressures reduce the contact patch size and reduce braking and handling capability.

 

Actually, that is a myth. I ran my Yokohama Blue Earths at 65 psi for 100k miles and there was very even wear. I would have kept them longer, except winter was coming and I wanted more tread. Contact patch is the same on current tires designs (except knockoffs). That was true on old designs. I had no braking or handling problems, even in snow. There are other forums (CleanMPG) that have discussed this for years. A whole lot of research has gone into this. But to each his own. Do what you feel is safe.

 

That's interesting...
I've had my 2020 Prius Prime Limited for about a month and a half now and decided to check the tire pressures yesterday morning for the first time. I didn't feel the need to do it sooner because its a brand new car and the dealer surely took care of that during dealer prep, right?

All four tires were at 46 PSI. This was cold pressure - the car had been sitting all night and hadn't been driven before I checked them.
The ambient air temp was 75 degrees F.
I was shocked - the tire sidewalls say the maximum SAFE pressure is 44 PSI.
I fired off an email to the dealer salesman complaining about it (haven't heard back yet)

So just what do they do as part of dealer prep?

 

In your case, evidently not much. Here is a comment from our expert @Elektroingenieur about what pre-delivery service should include.
Rubber plugs installed at pre-delivery inspection? | PriusChat

 

How do you know your tire gauge is accurate?

 

The poor man's way is worthwhile: have three or four gauges, test the same tire with all of them. If they're all close chances are they're accurate. If there's an outlier that's likely what it is.

My preferred gauge happens to read 3 psi high (according to my other gauges). I continue to use it, just keeping that in mind (labelled it accordingly too).

 

I disagree. When I picked up my Prime, the tires were also super high. While accelerating, it would spin the front wheels like I was driving on ice (but I was on dry pavement). After reducing it to 35-40, the traction instantly improved.

There is a margin of safety in the maximum pressure. Obviously they don't explode at 1 psi over 44. But the margin of safety decreases with wear and with age. And we don't know which design parameter determines the maximum pressure. Maybe it's not the strength of the tire casing. It could be that it's traction or handling characteristics that are only tested up to the sidewall limit. So I would just stick with what the tire manufacturer recommends if you want to go higher than what the car recommends.

 

I drive my Prime at 44psi all the time, and always have. No issues.

 

Your dealership gun-decked the PDI.

If you're lucky, that's the only thing they missed.....

 

Its a digital gauge I bought years ago b/c I got disgusted with the inaccurate slide types. I've compared it to many other gauges, including the dealers. I'm satisfied that its accurate enough. To my way of thinking consistency is more important than accuracy. All the other gauges I've had give inconsistent results on repeated measurements. This one is consistent.

 

Not if you're worried that 46 is out-of-spec compared with a max of 44. That's less than 5%. Now, pressure transducers come in accuracies covering an absolutely enormous range. I've seen ones that were not within 10% and I just bought one that, no kidding, had its worst calibration point 0.0017% from true. That's the difference between 44psi and 44.00075psi. Of course, it was $3,400.

 

The cars are lashed down when they're on the car carrier ship. Tires that are inflated harder will lash more securely, less bounce, for a safer ocean transit.

Of course it's the dealership's job to correct the tire inflation pressures. What do they actually do for the car with the predelivery process? Make it pretty.

 

That first pic had me thinking: they have to bring the cars in row-by-row, so the driver's can hop out of the driver's door, without being blocked.

 

I think it is MUCH more likely that one (or more) of their "technicians" thinks that the "right" pressure is the one listed on the sidewall.
I try to remember to check mine BEFORE leaving the service shop.
About 1 in 4 visits, they mysteriously end up about 10 PSI higher than they started out.

 

Watch this. The valet parking lot in Boston does the same thing albeit in much smaller scale.