Looking for Tire recommendations for my 2020 Prime

I have no idea how the tire pressure would influence the alignments. But if it does, I probably never had a correct alignment on my car. My tires are almost always off not by much but by 2-3psi higher than specified tire pressure for the OEM tires. Some Prius owners habitually overinflate the tires all the way to the max psi of the tire. But I have never read anyone complaining about the alinement being off. I would not think tire pressure affects alinment at a noticeable level, even if it really does affect it.

 

My Nokian Nordmans take 50 lbs, It snowed here yesterday and a chance is in the forecast today. brrrrr

 

Do you mean 50 psi? We are getting the late-season storm now. But the temp is just above 32F. It will be mostly gusty rain in our area. Of course, I just changed all snow tires back to AS tires. Not expecting any more accumulating snow this season. But we have had snow as late as into May in the past.

 

Had my summer tires put on last week. This morning? 15cm of snow. Yay!

 

@Salamander_King the 50 lbs sure wasn't the tire load rating . I think it was almost clear enough the way is was. But yes your call is accepted as the correct label. 50 psi or 50 lbs per square inch.

 

Yeah, inflating a tire all the way to the limit can be a fun experiment. I have only gone up to 42 psi on my tires rated 51psi max. I didn't notice much mpg improvement, but the ride just got harsher. I settled at 2-3psi above the recommended pressure at 38 psi in all four corners.

BTW, I had to look it up, but the pressure of 50 psi is only 3.45 bar. My manual espresso machine pushes boiling hot water through the coffee grain at 9 bars of pressure. So, 50 psi is relatively low pressure... LOL

 

I was wondering what took so long for you to reply. google must be out to lunch.

That's a lot of pressure for expresso, does it make foam too?

Air um up! I usually stop at 40 too, unless I'm seating the bead.

 

Do you mean frothed milk? Then no. My manual espresso maker is just for a shot of espresso. But it creates beautiful crema if that's what you were asking.

 

Mostly camber and caster I would think. Toe and thrust angle should only depend on the left–right direction of the front and rear tires.

 

This shows how little Toyota knows about tires.

Looking at Page 14 of the inflation tables I posted, the load rating at 35 psi for the P195 P-metric tire is 1279 lb and saturates at 35 psi. If you look at Page 34, the same load rating is at 33.5 psi for the 195 ISO-metric tire, and saturates at 36 psi, where it reaches 1356 lb.

So, different load ratings (by 6%) and different pressure (by 1.5 psi) requirements.

 

I think Toyota understands the tire characteristic and did this intentionally, for the reason I commented. 2017 PP was 4 seater. It required less load capacity, so P195 at 35/36psi was sufficient. When they remodeled the PP to a 5-seater without adding much weight to the car, they now had to use tires with higher load capacity for the extra passenger. Thus they used 195 (without P) with a higher load index to allow the 5th passenger to be in the car. It makes the perfect sense to me.

 

You mean 195.

That's a plausible explanation.

Also, if you switch from P195 to 195 and vice versa, simply have a four-wheel alignment done so that the new tire shape and/or pressure won't throw off your alignment. Of course, never mix P195 with 195.

 

Yes, I caught that myself and edited it. But not fast enough.

I really don't understand how the different tires especially P to ISO of the same size would affect the alignment. If that is true, then every PP owner who put different size wheels and tires would be having the alignment thrown off. In fact, if the load index difference is the only difference between P195 and 195 tires, then using a different brand of tires with the same size P195 to P195 or 195 to 195 having different load index would throw off the alignment. I have never heard or read such remarks. Nop, I am not wasting my money on unnecessary alignment unless I have a reason to believe alignment is off, such as a car pulling to one side, or tires wearing unevenly. I never had those problems when I was using P195 summer and 195 winter tires on my 2017 PP.

 

Even changing the tire pressure changes the alignment. Every alignment technician knows that. Simply hook up the alignment sensors and watch what happens when you inflate or deflate the tires. Pressure changes the shape of the tires. Likewise, P-metric and ISO-metric tires have different shapes, and the alignment will be different if you swap one for the other.

 

With that explanation, I would have to re-align my vehicle every morning and night. By simple daily temperature changes and driving the car, the tire pressure fluctuates +/- 5 psi every day. Sorry, even if what you say is true, I see absolutely no merit in performing alignment simply due to tire changes or pressure changes. If the alignment changes, then it is unavoidable changes the car sees every day and it is mostly nonconsequential requiring no owner intervention other than simply monitoring and maintaining proper cold tire pressure occasionally.

 

It's the ideal-gas law—you need to convert it to kelvin (K), which makes it more like ±1 psi between day and night.

For peace of mind, I wouldn't change between tire standards if I bought new tires. ISO-metric tires seem to be better, and if I switched to them when I bought new tires, I would ideally get wheel alignment as well, but the alignment shops often mess up the alignment than fix it. The dealers are probably better at alignment. Perhaps stick with the factory alignment until something goes bad.

 

Maybe in your region's night and day. In our region with 30F differential and driving on the road, I do actually see +/- 5 psi tire pressure daily flactuation. On winter days (30F) cold tire pressure set at 36psi would change to the lowest tire pressure in the morning (0F) to 32 psi, and to the highest 42 psi in the afternoon (30F) after driving ~30miles. I had TPMS monitor the tire pressure live on the display and this type of fluctuation happened very frequently.

And again, you can do whatever you wish to do with your car, but I am not buying the notion that tire changes or tire pressure changes require alignment. I may ask the dealer to perform the free alignment check when I bring the car in for other services, but I would not spend money or my time nor worry about the alignment being off every time tire or tire pressure changes.

 

I'm not buying that a change in P to metric sized tires affects alignment. They both have the same dimensions. Very few people on this forum adhere to the pressures on the placard anyway (most over inflate to get better mpg). Tires wear and a new tire tread depth is 10/32" and a worn-out one is 2/32". I'd think that would affect alignment more than a small pressure difference.

 

There is a range in the measurement of each ( alignment adjustment point a vehicle has) that is within manufactures specifications. The idea is to get all the adjustment points in a position where each measurement will be within those specs, (without having to add any aftermarket parts to the suspension.)
It's not rocket science, but it's getting there, probably sooner than later.

 

The reason for that pressure drop is the condensation of water vapor in the tire. Perhaps you should consider filling with nitrogen and getting green valve-stem caps, indicating nitrogen filling. Ideal-gas law (if you had nitrogen instead of humid air), would give 255 K / 273 K × 36 psi = 34 psi. Tire pressure is measured when tire is cold.



ISO-metric tires have rounder profiles than P-metric tires, which would change the camber. Here are the Toyo NanoEnergy A41 (ISO-metric) vs. A29 (P-metric):