danny662boy

I just got some sweeet winter tires; 15's. 185/65/15. My question. Currently I have all 4 tires set to 32psi.
When I have my 18s on I have it set to factory settings of 32psi in the front ad 29psi in the back.

Just wondering what to put the Psi on these Winter tires?

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keroRS5

Look at what the sidewall says max pressure is. Subtract 5-10psi according to your liking

SquallLHeart

have them at the factory recommended settings... regardless of tire size, tires should be at the same psi..

now, remember those settings are what the tires should be at when cold... so obviously when it's winter.. you might need to inflate them more to get it to the right psi...

and when it gets warmer.. make sure to decrease it to match the psi settings it needs to be.

engifineer

Never do this. Run what the info in your owners manual or on the door jamb says to run. That accounts for the weight split and overall weight for the particular car. The max pressure shown on the tire is not meant in any way to tell what pressure to run them on your car.

danny662boy

Ok cool so I will keep them at 32 psi in front and then 28 in back. How often should I check since its winter now? Once a week?? Temps have been fluctuating from freezing 32 and lower to almost 50. During a week

Turbo5upra

Once a month unless something looks off should be good... I've bumped pressures by 3-4 over the door sticker.
But that's to make up for garbage sidewalls on some Ventus v12s. Snows I run the factory pressure.

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engifineer

A 10 degree change in temp equals roughly 1 psi. So if the temp drops from 50 to 20 over a couple of weeks, for example, it is a good time to check. Other than that pressures will drop a small amount over time, so you should check them monthly or so anyways.

danny662boy

Does it matter if I drive a few miles to a gas station to put air in the tires ? Or will that throw temps off and psi since I drove on the tires warming them up a little?

keroRS5

It's a good indicator though when manual/door jamb info is not available. The max pressure for a tire of a certain size is usually in the range of 5-10psi from what most manufacturers recommend (for that tire size)

engifineer

I have seen many max pressures rated at 50 psi and above. Run that and see how often you replace tires and how poor handling is. The is a recommended pressure on most tires, which is lower and closer to spec. But, i have never owned a car missing that door jamb info, even cars that were as old as me. So most times the info is available. And if not you are better off running what a similar weight car runs.

keroRS5

Those tires are usually larger and made for vehicles which should run at higher PSI. I've encountered dozens of vehicles with no info on the door jamb/manual missing, working with cars from auctions and such. Of course it is better to find the real specs, but when you're at a gas station getting air you don't have time to call the dealer and ask for specs, or look it up online, so honestly, I wouldn't call it a bad rule of thumb to remember.

engifineer

A better rule if thumb is that on most vehicles with relatively close to stock pressures, you should not exceed about 35 psi if you don't know what to run. On very,
very light cars, stay closer to between 26 and 30. Then take the time to find out the correct pressure. That will keep you within range for most standard passenger cars.

My old Saturn that weighs 2300 lbs runs mid 20's for pressures ( max rating on its tires 50 psi by the way ;) ), my tC which weighs 2900 runs 32/29 and our 4 runner runs mid 30's
The Sonata rental i am driving this week states 45 psi max on its tires, yet runs 32.

Max pressure simply means the maximum pressure that tire can absolutely and safely handle and is not necessarily related to the type of vehicle. So it can be close , or way the heck off.

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Turbo5upra

Max pressure is usually for seating the bead...

engifineer

Yep, the max they can safely use to do so, although that is many times exceeded :p

I dont even aporoach the max rating on my autox tires, which typically need to be run at higher pressures. To keep the tire rolling over just to the arrows on the tread i am still well below max