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baywatch
02-25-2009, 09:26 PM
Ok, The tag in my door on my truck says 65psi on the front tires and 75psi on the back. The tire itself says max cold psi @80.

Where should I keep them? My guess would be put them all to 80psi when Hauling heavy load and follow the door when I am just doing daily driving.

I don't really claim to know much, so what do you guys do.

Thanks,

Josh

MarylandMark
02-25-2009, 09:39 PM
I go with the door but good question!

I figured the tire is made for like 100 vehicles so has a general rating but the door sticker tells me what to set it at for my vehicle.

I put my like 5% over- they lose a little air most of the time and gives me better MPG I think

inbetween
02-25-2009, 10:47 PM
As long as the tire is equivalent in size and rating to the original tire, go with the psi on the door. The vehicle's ride, handling, safety and fuel economy were designed to to work with those pressures.

Blue Oval
02-25-2009, 11:01 PM
What year is the truck,does it have the tire pressure mont. system?If you don't keep the air in the newer trucks to specs the tire light may come on.

inbetween
02-25-2009, 11:21 PM
What year is the truck,does it have the tire pressure mont. system?If you don't keep the air in the newer trucks to specs the tire light may come on.

good point, I forgot about the tire monitors

Griff
02-26-2009, 03:07 AM
If they are the stock size and load rating, then go by whats written in the door or close to it. Mine says 55# front and 80# rear. I run about 60# front and 75# rear. The tires are rated at 80psi.

baywatch
02-26-2009, 04:43 AM
What year is the truck,does it have the tire pressure mont. system?If you don't keep the air in the newer trucks to specs the tire light may come on.

Thanks for the responses guys. It is an 08 Dodge 3500, and If the the tires are low the tire monitor will come on (That is actually what made me check my tire pressure in the first place).

Thanks again..

Bgchuby01
02-26-2009, 09:58 AM
Always go by the psi on the tire. If you have a failure and the tire is the cause they will look at the psi in the other tires.

baywatch
02-26-2009, 10:55 AM
Always go by the psi on the tire. If you have a failure and the tire is the cause they will look at the psi in the other tires.

So then, are you saying to go by max cold psi on the tire rather than what the door says? Or are you just saying make sure that you are at least congruent with the door recommended psi in the event of an "incident" they will check the other tires?

Thanks,

slowride33
02-26-2009, 03:50 PM
2005 GMC 3\4 ton says 55 up front and 80 rear. I run the rears at 70 during the winter months cause I know I won't be hauling the boat at all, gives a little smoother ride with less pressure in the rears.

sledge
02-26-2009, 04:20 PM
"max cold psi" is what gives the max load rating, NOT necessarily what you should run the tires at every day. You can't go wrong with the door sticker. If you're not carrying a heavy load, losing a few psi in the rear shouldn't hurt as well as carrying a few more in the front.

Also remember a general rule that psi changes with air temp: 1psi per 10degrees. So if you started with 55/75 when it was 70F, you can lose 5psi during winter. Final thought: it's better to have a little more than a little less.

inbetween
02-26-2009, 09:40 PM
Thanks for the responses guys. It is an 08 Dodge 3500, and If the the tires are low the tire monitor will come on (That is actually what made me check my tire pressure in the first place).

Thanks again..


Always go by the psi on the tire. If you have a failure and the tire is the cause they will look at the psi in the other tires.

For the tire monitor required by the gubment for an '08 vehicle, go by the label on the door or the check tire light/message will come on.

Tempest38
02-27-2009, 12:39 AM
Remember in the real heat of summer especially on long tows you can Gain pressure. Keep it in mind.... Just my two cents...

cpmarine
03-01-2009, 10:09 PM
The max pressure on the tire is the pressure required when the tire is loaded to it's capacity. I am always close to max weight so I go by what's on the tire. If you're just using your vehicle for personal use you should probably do what the vehicle manufacturer says, what is stamped on the door.

Chris
03-07-2009, 07:25 PM
If it's something like a Ford Explorer where the engineers f'ed with tire pressure to get the trucks to stop rolling over, stay with the door sticker. If it's a real truck (250/2500+) then go with the tire. Heat kills tires. Tire flex generates heat. The more air, the less flex. They may not ride as well, but they'll do the job- plus you'll pick up MPG.

FULL FORCE
03-09-2009, 02:07 AM
Mine are rated at 80 psi, I run them at that all the time, I agree with more is better, I also tow alot, even in winter, truck feels stable all the time, I can care less about ride, rides good for a F250 to me..

Tony M
03-09-2009, 10:02 AM
THERE was something in the news about changing your air to some other psi but can't recall what the H it was , they would let the air out of your tires and fill back up with ???? and you could pick up 1 or 2 MPG . :)

njthumper
03-09-2009, 04:55 PM
THERE was something in the news about changing your air to some other psi but can't recall what the H it was , they would let the air out of your tires and fill back up with ???? and you could pick up 1 or 2 MPG . :)

Fill with Nitrogen, Nascar cars run with it.

RollWithIt
03-09-2009, 06:51 PM
I typically go with the rating on the tires since that is what the tires were engineered for. Especially on my truck since I switched to bigger tires than came on it stock. But on my vette, the tires are rated at 50 psi cold. If I go over 40 psi the tire monitor sensor comes on saying I have too much pressure. I usually set those tires at 35 like it says on the door unless I plan on doing some hard running, then I raise it.

Tony M
03-10-2009, 09:40 AM
Fill with Nitrogen, Nascar cars run with it. JUST COULD not remember for chit what it was ! :sifone:

WOTW2E
03-11-2009, 01:59 PM
The advantage of nitrogen in a tire is that there is little change in pressure due to changes in temperature. As noted air pressure will increase as the tire heats up. Nitrogen is more stable, thats why it is used for nascar where they are making 1/4 psi adjustments.

Anybody have any first hand experience of an increase in mpg using nitrogen on our daily drivers?

Chris
03-13-2009, 07:54 AM
Nitrogen is just the latest marketing buzzword for the tire industry.

Your tires already have 79% nitrogen in them. The reason nitrogen leaks out more slowly is their molecules are larger than oxygen's. The individual oxygen molecules slip out between the molecules in the tire. The aviation industry uses nitrogen because it's inert, not because it doesn't leak. They check pressures pretty regularly and no flights are long enough to have a measurable drop.

As far as temperature-effect PSI changes, your tires were engineered under the assumption that they would be filled with air and any heat-related pressure changes were factored in.

cigdaze
03-13-2009, 08:12 AM
As far as temperature-effect PSI changes, your tires were engineered under the assumption that they would be filled with air and any heat-related pressure changes were factored in.
Yep. Exactly why the stamp reads "Max Load at XX PSI Cold."

outriggers
03-13-2009, 11:57 AM
I use nitrogen in all my tires. There are some other advantages, althought I think the extra MPG thing is bs. If the pressure is rite, its rite. There is no water or moisture in nitrogen. Ever have a aluminium wheel corode to a tire or have the bead corode so it leaks? I have also been told that in tires that sit alot that they dry rot less because there is no oxygen. The snow tires for my car were stored all summer, I put them on in December and the pressure never changed. I think thats were the extra mpg thing comes from because most people don't check so they are lower than they should be. I buy it by the bottle from a gas outfit. I do think its their is a profit motive and I wonder about the quality. Like Chris says in aviation the pressure is checked alot. If the pressure is low in one tire by a %, that tire and the one next to it also has to be changed. If one tire was low that means that the one next to it was overloaded. On the airplanes I fly, each main gear tire has about 40,000lbs riding on it. (4 tires to each truck), with a 225 mph speed rating. Heat is also a big issue, you don't want oxygen in a very hot tire. Sorry totally off topic, my .02 Doug

KYElimEagle
04-21-2009, 06:25 AM
Lower pressure in my front tires on my F-250 leads to more uneven wear on my front tires. I run 75 lbs. not as good ride but seems to handle better and wear better. I am sure better mileage.

US1Fountain
04-25-2009, 12:56 AM
Anyone ever use the chaulk method to determine tire pressure?

Pachanga
04-25-2009, 07:39 AM
Lower pressure in my front tires on my F-250 leads to more uneven wear on my front tires. I run 75 lbs. not as good ride but seems to handle better and wear better. I am sure better mileage.

I just received a letter from Ford warning about running tire pressure to low on my 250 4X4. Apparently some trucks will develope a severe shimmy after hitting a bump! Too stop the shimmying the truck has to be brought to almost a complete stop. Ford says this is due to running tire pressures too low.