I just purchased 2004 F-250 extended cab long bed 4X4. It has General tires on it side wall says 80psi cold but dealership told me that they need to be run at 50 psi. Fronts seem to be squatting way to much who do I believe Ford (firestone problems because of underinflation) or the rating on the tire. Thanks Andy

 

The 80 psi on the sidewall is likely the maximum amount of tire pressure that the tires can safely hold. You really should look at the inside of the door jam or the inside of the gas cap door for the accurate tire pressure for your truck. There should be a sticker whichs gives the appropriate pressure. I have a a 2003 F250 4X2 and mine calls for 70psi for the rear tires, 50 psi up front. Like you, I thought that 50psi was too soft of a ride, so i've been running 60psi up front and it feels pretty good.

 

Thanks for your reply but I am not sure what ford has to say about tire pressure is not just for there best interest. I believe part of the problem with the ford/ firestone problem was fords fault by haveing the tires underinflated so there vehicles would pass rollover tests.

 

I Just got new tires for my truck.

I ran 60 psi for 33,000 and they wore dead even. They are still legal too. I had the generals as well.



I can see ford Thinking about themselves with the rollover testing. But if there was to be a problem, they'd blame you or the tire manufacturer.

Personally, I think it's a bigger risk to run pressure too low. Especially if you have any kind of load on.

The low pressure could actually cause a roll over in its self. as you turn the uninflated part of the tire may roll under itself and blow the tire seal.

 

Hmm.. mine won't help, with my tires i run 33 psi in the front and 30 psi in the back.

But, back when i had my 35's i was running 50 psi all the way around and that seemed pretty good. The sticker on my fuel cap says 80 psi in the back, and with any tire that seems like a whole lot. i would say play around with the psi's some and find what "feels" best.

 

The higher pressure listed for the rear tires is for when you are carring your maximum weight rating. Obviously, the front tires are always carring around the same weight while the rear tires sit under a bed that is sometimes empty and sometimes full.

I run my rear tires at the same pressure as recommended for the front when I'm empty and pump the rear up when I tow my camper. This seems to make the empty ride a lot smoother and the tires are ready to handle the load while towing.

Edmo

 

I don't know what engine you have, but I got an inflation chart from the tire manufacturer, and I run way more up front when empty due to the weight of the diesel. When I tow or carry, I pump up all the tires to close to max. It extends tire life and improves handleing.

 

thanks for the replys, dealer was full of it 50 all the way around tag on drivers door 65 front 80 rear. this also does not make sense to me because weight of diesel but truck handles better. Thanks Andy

 

For Ford trucks, there’s 2 types of tires possible. Small trucks like a Ranger will probably have Passenger car tires installed. Passenger car tires start with P in the part number. Trucks like a F350 will come with Light Truck tires. Light truck tires start with LT in the part number. These 2 tires are built to different standards and have different pressure requirements. Passenger car tires have a max inflation pressure listed on the sidewall. Light truck tires do NOT have a max pressure listed on the sidewall. Go outside and look at one; it only has a max load at a listed cold pressure. My comments following apply to Light truck tires.

The label on the door jamb is assuming a truck is loaded to the GAWR’s (Gross Axle Weight Rating). If you are operating at a lower weight, you can reduce the pressure for better tire wear, smoother ride and better traction. The label is also assuming you have stock tires as delivered from the factory. If you have a different tire installed, you need to use the correct pressure for the tire installed.

Here’s the proper way to determine what pressure to run in your tires. Weigh your truck, getting individual weights for each wheel (or at a minimum each axle). Then consult the tire inflation chart for your brand/model of tire. The chart will tell you what pressure to run based on your weight. If you got individual wheel weights, use the heaviest wheel on an axle to determine what pressure to run on all tires on that axle. If you weigh your truck unloaded you’ll need to do this again with your normal load. If your load fluctuates all the time, it’s probably easier to just keep the tires inflated to handle the highest load you anticipate.

In my case, I carry a 4000 lb slide-in camper occasionally. I keep the truck tires inflated for unloaded driving most of the time. Then before I load the camper, I pump them up for the extra weight. That way the truck rides smoothly with good traction and even tread wear while unloaded. If I was loading and unloading the camper daily or even weekly, I’d probably just keep the tires pumped up. Changing tire pressure daily on a dually would get old real quick.

It's a good idea to read the footnotes and fine print in tire inflation manuals also. For instance, in the Firestone manual it says that if you are driving for long periods at 65 to 74 mph, you should increase the tire pressure 10 psi (provided the wheels are rated to handle the pressure). In the case of the Firestone Steeltex 265/75-16 tire that would be 90 psi if you are at max load. This means that the 80 psi listed on the sidewall is not the max pressure. If you want to drive 75 to 84 mph , you still need those extra 10 psi, but you also need to reduce you max weight capacity by 10%.

You can view a tire inflation table for LT235/85-16 tires at http://www.goodyear.com/truck/pdf/LoadInflLTMetric.pdf .

Here’s the inflation table for the LT265/75R16 Firestone Steeltex tire

Weight Pressure
1910 35
2100 40
2280 45
2470 50
2625 55
2790 60
3000 65
3105 70
3260 75
3415 80

If you are driving at higher speeds for extended periods, you need to add more air:

65-74mph add 10psi
75-84mph add 10psi & decrease max load 10%

 

I'm not sure if this will add anything to the conversation but here's an inflation trick I learned when iron-butt riding bikes long distances (like 1000 mile days - Maine to Daytona in 34 hrs). Take tire pressure cold - drive about 20-30 miles to get the tires warmed up and check pressure.

If the pressure has increased more than 10% of the first reading your tires are underinflated - (too much sidewall flex and that generates heat) so you have to add some air pressure. If the new tire pressure is less that 5% over the cold reading your tires are too hard and you can let some air out for a more comfortable ride.

This had the advantage of being a "rule of thumb" I could utilize almost daily whatever the load on my bike was without having to weigh anything. I don't see why this idea wouldn't work for trucks too