Tire Pressure ?

[Mark McGuire]

Hey Guys,
Leaving in the morning on vacation. Checked tire pressure, all tires are 32 psi, that's whats on the tires. On the door it say's to run 30 in the front, 35 in the rear. Which one do I do?
TIA,
Mark

[RamAirV1]

Re: Tire Pressure ?

Originally posted by Mark McGuire
Hey Guys,
Leaving in the morning on vacation. Checked tire pressure, all tires are 32 psi, that's whats on the tires. On the door it say's to run 30 in the front, 35 in the rear. Which one do I do?
TIA,
Mark

You should probably increase the pressure in the rear to 35 PSI. How much luggage, etc. are you hauling with you?

32 PSI in the front will give a stiffer ride than 30, though the tires should handle that just fine.

Be sure and check the tire pressure while they are cold.

RamAirV1

[Tim Lingor]

Hey Mark,

When you say that is the pressure on the tires, or is that pressure in the tires? You do not want to exceed the max. cold psi listed on the sidewall.

If the tires are the OEM ones, and the sidewall allows it (which it should if they are OEM), then I will follow the manufacturers recommendation.

Have fun on your holidays!!

Tim

[rusty bumper]

Re: Tire Pressure ?

Originally posted by Mark McGuire
Hey Guys,
Leaving in the morning on vacation. Checked tire pressure, all tires are 32 psi, that's whats on the tires. On the door it say's to run 30 in the front, 35 in the rear. Which one do I do?
TIA,
Mark

I always go by the sticker on the door........But I don't exceed the maximum PSI rating on the tire sidewall.

[Murr1525]

My dad and I were just discussing this issue... His tire sidewalls say 42psi, the door says 32psi. ( I may be off a psi or two). But thats a big difference, and finaly we just said maybe 38-40 would be good. though I think 42psi would be best for milage, if a slightly stiffer ride.

I think the tire rating will be best for mileage, and the door panel rating is for the 'comfortable' ride over bumps, etc.

[Mark McGuire]

Thanks Guys,
I will check them cold, and make adjustments according to the ratings on the tires for better mileage. When we get to Williamsburg I will change to the ratings on the door for better ride. First trip for the new Trailblazer. Thanks again.
Mark

[2000]

Originally posted by 2hotford
Hey Mark,

When you say that is the pressure on the tires, or is that pressure in the tires? You do not want to exceed the max. cold psi listed on the sidewall.

If the tires are the OEM ones, and the sidewall allows it (which it should if they are OEM), then I will follow the manufacturers recommendation.

Have fun on your holidays!!

Tim

I have after market tires on mine, but their the same load and speed ratings. so are you saying you follow the door, or the tire?

[Tim Lingor]

Originally posted by 2000
I have after market tires on mine, but their the same load and speed ratings. so are you saying you follow the door, or the tire?

Good question 2000!

When the manufacturers provides the tire pressure on the door, they are providing the suggested pressure to allow their vehicle to perform as advertised. For example: ride quality, ABS programming, tire wear etc... . However, when a person changes the parameters, like adding a heavy load (hauling or towing) then a person "may" need to adjust the pressure based on those circumstances. My truck calls for 55 psi front and 65 psi empty OEM(I think; I will check today). It should, as far as I know, haul/tow its GVWR at those OEM tire pressures. Too much pressure for the load size will cause the tires to wear in the center. Too little tire pressure with cause the tires to where more on the edges. (We won't even get into tread patteren considerations! )

But when I am towing/hauling a heavy load, I increase the tire pressure to 75 psi front and 80 psi back (my E rated tires have a 80 psi max). (My truck and trailer combined is over 16,000 lbs!) Under-inflated tires tend to over-heat when they are carrying a heavy load. Also, when towing, I use 1000 lbs rated weight distribution tow bars. These tow bars equalize the height of the truck by distributing the hitch weight to both the front and back of the truck. As such, this places more weight on the front end compared to a stock truck that is running empty.

If you are running empty, but have aftermarket tires, which may be a different size, then you need to make some changes. If they are the same size and load rating, follow the door sticker for normal use.

For an empty truck, if the tires are a different size compared to stock, one trick I used to use is to take tire chalk and make a stripe across the tire's tread, Then drive in a straight line for about 50 feet. You should have ~1/2 inch of chalk on both edges of the tread. If you have more, lower the tire pressure. If you have less chalk, then raise the tire pressure. I idea is too increase the surface contact patch of the tire in order to get the max performance.

Tim

[jfelbab]

FWIW, the tire pressure indicated on the tire is the "Maximum Inflation Pressure", not to be confused with the optimum air pressure. Generally it is a good idea to use the auto manufacturer's recommendation. If you are heavily loaded you can add a couple more pounds. Under inflation can kill a tire quickly. Inflation to the maximum will cost you comfort and poor handling.

Your tire pressure will increase or decrease one pound for every ten degree shift in temperature. Check the pressure cold.

If you set your tire to the tire's maximum value when it is cold and then drive the vehicle hard the tire pressure will exceed the manufacturers recommended maximum.

You may wish to experiment with the pressure up or down in half pound or whole pound increments and see if you like how your vehicle handles. A couple pounds of air up or down can make a major difference in handling.

It's also a good idea to check the pressures regularly every week or two.

My MR2 handles best with 30 front and 33 rear. My RX330 likes 34/34.

[DodgeStratusR/T]

32 is fine dont waste your time going to the pump.

[Mark McGuire]

update

Well guys, I left the pressure "as is" from the dealer, 32 all around. The ride was good, did not feel overloaded or pushy while driving. Ran 70 mph, avg. 20.7 mpg. On the trip home I will try the door ratings and see how it goes.

On a side note my wife thinks I've lost my mind. After driving 2hrs to pick up my brother in Mooresville, I thought the blazer was to dirty so "I washed and dried it while they waited" I think I've gone "Car Crazy".

[rusty bumper]

I agree with Tim & jfelbab.

My best wear pattern has always come from the using the door sticker numbers, but sometimes I might make adjustments according to the load.

[2000]

this is very helpful, but why would Marks sticker say to run more than the tire says is the max allowed? being a new truck I'm sure they're stock tires, right Mark?

[rusty bumper]

Originally posted by 2000
this is very helpful, but why would Marks sticker say to run more than the tire says is the max allowed? being a new truck I'm sure they're stock tires, right Mark?

32psi for a maximum tire rating doesn't sound right to me.....At least not on tires for a vehicle as big as his.

As a matter of fact, I've never seen a tire that was rated at 32psi. Course, they might be out there, but I've yet to see any.

If his tires are max rated at 32psi, then he needs to take the vehicle back to the dealer and have them replaced.

Something's screwy here IMO.

[Mark McGuire]

Hey Guys, 32psi is not the max for the tire, that is 44psi according to the sidewall. The 32psi is what the dealer put in them before they turned it over to me. Sorry for the confusion. That should be 32 in the tires not on the tires.
Mark