Tire air pressure.

ZenUber

Well-Known Member
For the mechanics out there. The tires say max pressure 44 PSI ,and the door says cold tire pressure 35 PSI. What number should I go with? And are my tires still considered cold If I drove a couple miles to the gas station? It’s a Chevy Traverse - usually only have one or two passengers.
 

FLKeys

Well-Known Member
Go with the ratings on the door, the tire rating is a do not exceed for the tire and nothing to do with your car.

If it is warm outside and the tires have been driven on a little bump it up a pound or two and then check it first thing in the morning and see if it is where it should be according to the door sticker.

I use nitrogen in my tires from a nitrogen tank, I inflate my tires to 3# over the cold tire pressure because nitrogen is not subject to as much pressure change like regular air is from heat. Also I have found with regular air my tire lose on average 2# a month where with Nitrogen the molecules are bigger and I only lose around 1/2# per month.
 

TomTheAnt

Well-Known Member
The nitrogen thing is interesting...

Normal air consists roughly 80% of nitrogen, so at least for me it doesn't make sense to pay for it. Yes, they hold consistent pressure longer, but I check mine every week, anyway, so not a huge issue. And yes, I had to pay for my 26-gallon air compressor from harbor Freight and all that, but that's used for other things that just tires, anyway.
 

FLKeys

Well-Known Member
The nitrogen thing is interesting...

Normal air consists roughly 80% of nitrogen, so at least for me it doesn't make sense to pay for it. Yes, they hold consistent pressure longer, but I check mine every week, anyway, so not a huge issue. And yes, I had to pay for my 26-gallon air compressor from harbor Freight and all that, but that's used for other things that just tires, anyway.

There is a lot of debate on the nitrogen issue, I would never use a nitrogen scrubber as I consider that a waste of money. I got a used Nitrogen tank on Craigs List for $5 and it had a regulator with broken gauges, regulator works gauges don't, no issue filling car tires. I paid under $10 to do a tank swap at a welding shop. I get about 2 years out of it for 2 cars and 4 bicycles. I like not having to fill mt tires all the time.
 
It's better to be slightly overinflated than underinflated. Over inflation is generally better for mileage/wear, and protects against slow leaks, but you have to decide whether the rough ride and potential greater suspension wear is worth it.

I will describe the method I use for filling tires: I use a cheap 12v compressor. Remember that as a rule of thumb, you get 1 psi for every 10f in temperature.

To get the minimum tire pressure:
Suppose the temperature right now is 55f, but I know that temperatures may drop to 35f (-20f). I know that the recommended tire pressure for my prius is 35/33, so I over shoot the tire pressure by 2 psi and fill tires to 37/35, so that if temperatures drop to 35f I will still have 35/33 in my tires.

To get the maximum tire pressure:
Again suppose temperature right now is 55f, but I know temperatures may increase to 85f (+30f). I know that max tire pressure on my michelin defenders are 44psi, and I know I have to maintain a 2 psi difference between front and back. So I will fill my tires to 41/39, so that if temperatures rise to 85f I will have 44/42 in my tires.
 

ZenUber

Well-Known Member
Go with the ratings on the door, the tire rating is a do not exceed for the tire and nothing to do with your car.

If it is warm outside and the tires have been driven on a little bump it up a pound or two and then check it first thing in the morning and see if it is where it should be according to the door sticker.

I use nitrogen in my tires from a nitrogen tank, I inflate my tires to 3# over the cold tire pressure because nitrogen is not subject to as much pressure change like regular air is from heat. Also I have found with regular air my tire lose on average 2# a month where with Nitrogen the molecules are bigger and I only lose around 1/2# per month.
Cooool. Never heard of using nitrogen.
Post automatically merged:

It's better to be slightly overinflated than underinflated. Over inflation is generally better for mileage/wear, and protects against slow leaks, but you have to decide whether the rough ride and potential greater suspension wear is worth it.

I will describe the method I use for filling tires: I use a cheap 12v compressor. Remember that as a rule of thumb, you get 1 psi for every 10f in temperature.

To get the minimum tire pressure:
Suppose the temperature right now is 55f, but I know that temperatures may drop to 35f (-20f). I know that the recommended tire pressure for my prius is 35/33, so I over shoot the tire pressure by 2 psi and fill tires to 37/35, so that if temperatures drop to 35f I will still have 35/33 in my tires.

To get the maximum tire pressure:
Again suppose temperature right now is 55f, but I know temperatures may increase to 85f (+30f). I know that max tire pressure on my michelin defenders are 44psi, and I know I have to maintain a 2 psi difference between front and back. So I will fill my tires to 41/39, so that if temperatures rise to 85f I will have 44/42 in my tires.
Wow, I like the science and the math. Thanks for the detail.
I plan on checking my tire pressure on a weekly basis, so I’ll have to take temperature changes into account. That 1psi per 10 degrees f will really come in handy. I would have been scratching my head without that knowledge.
 
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Ubermcbc

Well-Known Member
For the mechanics out there. The tires say max pressure 44 PSI ,and the door says cold tire pressure 35 PSI. What number should I go with? And are my tires still considered cold If I drove a couple miles to the gas station? It’s a Chevy Traverse - usually only have one or two passengers.

Go to the nearest hub and ask the same question. They will guide you better. Please make a video so we can see their facial expressions. Your video will go viral. Lol.
 

Atom guy

Well-Known Member
For the mechanics out there. The tires say max pressure 44 PSI ,and the door says cold tire pressure 35 PSI. What number should I go with? And are my tires still considered cold If I drove a couple miles to the gas station? It’s a Chevy Traverse - usually only have one or two passengers.

Love the individual readouts for tire pressure that GM does. Makes it a lot easier to figure out which tire has the latest slow leak
 

ZenUber

Well-Known Member
Love the individual readouts for tire pressure that GM does. Makes it a lot easier to figure out which tire has the latest slow leak
Yea, the reason I posted this was because I’m getting a message on the dash that my right front tire is low.
 
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