Tire pressure PSI question need help . Read details?

Question

So i got new tires on my Scion and the tire PSI right now is set to 43 PSI on my new 18 inch tires .

The max it says on all 4 on my tires are 50 PSI .

However Toyota recommends 30 PSI on back and 32 on front .

So should i keep it the way it is at 42 PSI or deflate the air to the recommend 32 PSI .

Answer 1

run them all at 40 psi.... thats what i run mine at and i get good gas milage and normal tire wear.

Answer 2

The tire pressure recommended on the door post on our Avalon is 32 PSI. The local Toyota Dealer recommended 36 PSI they say.

Answer 3

The higher pressure will extends the tier life, the Toyota pressure gives you a softer ride but the tiers wear faster. I would leave it at 42 lbs longer tier life.

Answer 4

However Toyota recommends 30 PSI on back and 32 on front .



Do that.

Answer 5

I'd just run them at 35 PSI.

The Max. rating on the sidewall is only for the maximum air you can put in the tire to seal the bead to the rim and has nothing to do with the inflation pressure for driving

Answer 6

Sorta depends on what you want vs factory specs.

If most of your driving is regular street travel than lower PSI/factory specs should be fine but for longer drives a slightly higher PSI can increase milage. Harder ride VS better milage?

Answer 7

Since you're not using the recommended TIRES or wheels, the recommended tire pressure is irrelevant.



Wide, low profile tires (if you have them) on 18" wheels need more pressure to keep the tread flat on the pavement. How much more? That's up to you. Ask the tire dealer.

Answer 8

Toyota probably knows the handling characteristics of that vehicle.



ADDED: some here are recommending the same pressure, front and rear......even when the car maker recommends different pressures. I think it is important to maintain the car maker's recommended ratio. Example: I had a Jeep CJ - Jeep recommended different pressures front/rear.......invariably, when I had the oil changed the lube place would pump all tires to the same pressure - the result was tricky handling on that vehicle. The car makers usually know at least as much as the lube stop guys (just like when Chevy had specific pressure recommendations for the Corvair - - all the horror stories of them flipping-over were when the pressures were fiddled-with and recommended differential front/rear ignored).

Answer 9

Set it per vehicle. Toyota says 32 front and 30 rear, so do it that way. 42 will give you a hard ride.

Answer 10

Go with what Toyota recommends: 30 PSI in back, and 32 on the front tires. That's "cold" pressure: measure it when the car hasn't bee driven for a few hours.



43 PSI... I'd bet that you were bouncing all over the road. Or: is it possible that you have a bad gauge?



What matters here is the weight of the car. Toyota knows that number. The tire manufacturer does not.

Answer 11

NO NO NO! The tire maker knows more about their tires than the vehicle maker. Trust the PSI imprinted on the tires, which are probably not the original tires.

Answer 12

Try it and see what feels best. The lower pressure may feel more comfortable, but the higher pressure may give better gas milage

Answer 13

I run mine at 40psi

Answer 14

Run what the manufacture says to. If you load it to the max then add a couple of PSI (not 10). The max pressure rating on the tire only applies at the load rating on the tires which is probably much higher than the vehicle load rating.

Answer 15

Sounds like your replacement tires and wheel are not original equipment size and the recommendation would be different than stock. Ask the tire shop why the PSI higher than previous tires.

Answer 16

READ the whole warning message on the sidewall of the tire.



It usually states the MAXIMUM pressure, at the MAXIMUM rated weight of (#### lbs/kgs) on the tire, which is not the actual vehicle weight that's on the tire. Hopefully, the actual weight on each tire is significantly LESS than the MAXIMUM tire weight rating.



If the tire is the size that belongs on the car, then use the manufacturer's recommended pressure as is listed on the sticker on the drivers door or door jamb.



If you are confused because the tire is a different size than what originally came on the car, then call the tire manufacturer and ask them for their recommended pressure. They may ask you what the actual weight on each tire is.



-General automotive mechanic since 1972. Retired in 2018.

Answer 17

Read carefully what the tire says, it says something like: Maximum load 1819 lbs at 50 PSI. Are you running maximum weight? If you run max pressure and underload the tires you will balloon the tires and wear the center too fast, will have a harsh ride, and little traction.



I don't know what exact size and brand tire you have but I got the 1819 lbs off Goodyear Eagle P265/45r18's. A Scion xB has a curb weight of 3000 lbs, and a gross loaded weight of 4105 lbs. That's far less than the 7200 lbs the tires are rated for, you don't need 50 PSI !



But the rating on the door is between comfort and performance, I might boost the pressure to 35/36 for better performance, but would watch the tire depth wear.

Answer 18

IGNORE WHAT IT SAYS ON THE TYRE



try reducing PSI to about 35 and see how it feels then Go to 30 front and 32 Back

Answer 19

Use psi for the tires you are running.

Answer 20

The pressure on the tire is a max value, not a recommended value for your car.

Answer 21

You can guess. Or you can get the tire manufacture's chart for what PSI for how much weight the tire will be carrying. Then weigh each corner on your car carries.

Answer 22

Tyre fitters pump up tyres very high on initial fitment to ensure the tyre bead seats correctly on the rim. Let the tyre down to what Toyota recommend. They know what ground pressure the cars exerts and how much tyre compliance you need to have. As a rule, most cars need around 30 psi more or less. Only heavy vehicles that carry loads like trucks and 4WDs, need pressures around 40psi. The max pressure marked on the tyre is NOT the recommended pressure. The tyre maker can't know what car that tyre will be fitted to. The pressure on the side wall is the maximum permissible pressure for that tyre at max load, at it's rated speed. Think of it as a "never exceed" pressure. The max load and speed ratings are indicated by alpha-numeric codes on he tyre wall if you really want to research them.

Answer 23

Watch the tread wear patterns! Get a good tool to measure tread wear. If the tread in the center of the tire wears faster then the outside edge- decrease tire pressure. If the tread on the out side edges is wearing faster increase tire pressure.

Now if you read the fine print in the instruction manual it says "or manufactures recommendations" which interestingly is identical to the disclaimer from the tire maker!

I would suggest you go back to the place you bought the tires and ask them! They no doubt warranty them for at least a few things and as such you need to follow their recommendations.

Answer 24

I'd go about 35 psi per tire. Not enough to wear out the center but enough to keep the light off until the next oil change.

Answer 25

If you are running the stock tire & wheel size, then go with what the car says. The rating on the tire is just the max that it can handle, that does not mean its correct for the weight and performance on any particular car. The car manufacturer knows what your car needs.





If you have changed the wheels or tires, then you may need to adjust pressure. For example if you went with larger rims and low profile tires to achieve the same outer diameter, then you have less rubber between the rim and the road, and you may need a higher pressure to keep the tire stiffer so it doesn't flex and let the rim touch the ground if you hit a bump or pothole at high speeds. In that situation you need to use your best judgement and maybe consult the tire pros at the shop where you had the new rims & tires installed.

Answer 26

Tire pressure goes by the vehicle tag usually located near the door latch...