Tire Pressure

[Bigdog]

2018 F-250 Diesel with High Capacity Tow Package. Recommended psi is 60 front, 65 rear.

The virtually identical F-350 version of this truck recommends 60 psi front, 80 rear.

Is there any downside to increasing the rear psi on the 250 for a little stiffer ride while towing.

[dwaynebmsg]

I have a 2000 F 250 long bed that I used to tow our 35' Big Horn and always ran 60# front and 70# rear.

[Kevin Cooper]

The downside to higher inflation of tires. 1. Loss of some traction, tire touching pavement in smaller area. 2. Tires wear out tread faster, again less rubber on the road. Usually center wears faster. 3. Harder on tires when you hit a pothole. 4. Rougher ride.
Does it increase blowout chances? No.
Suggest you weigh your rig fully loaded, front axel, rear axel, total weight, trailer tires. Then get tire manufacturers charts, find your tire, find your weight, see suggested PSI. Do this for all your tires. Make sure you divide by # of tires per weight from scale.
Hopefully, you are not exceeding your weight limits! But you will know and feel better if below the numbers.
Best wishes, Kevin

[Bigdog]

Thank you for the thorough reply. I do have all of the weights by axle. Where is the best site to find the manufacturers tire charts?

[Kevin Cooper]

Tell me manufacturer name, series name, and tire size. Will try to find it.

[Bigdog]

Michelin LTX A/T2
275/65/20

[Kevin Cooper]

This should serve you well. Especially since you know your weight.
https://tirepressure.com/lt275-65r20-tire-pressure

Best wishes, Kevin

[CAG]

Originally Posted by Bigdog

2018 F-250 Diesel with High Capacity Tow Package. Recommended psi is 60 front, 65 rear.

The virtually identical F-350 version of this truck recommends 60 psi front, 80 rear.

Is there any downside to increasing the rear psi on the 250 for a little stiffer ride while towing.

What does it say on the side of the tire? That will be the max recommended tire pressure.



As mentioned, increasing tire pressure can do a fair amount of damage to the tire if it is over the recommended, including blowing tires out. Ask me, the Chevy dealer rotated tires on my Duramax, over inflated by 20-25 lbs due to a faulty pressure gauge and cost me three tires on a rocky back road. They paid for the new tires and tow.



Want a stiffer ride, install air bags.

[Kevin Cooper]

Max pressure on them is 80psi

[Bigdog]

Originally Posted by Kevin Cooper

This should serve you well. Especially since you know your weight.
https://tirepressure.com/lt275-65r20-tire-pressure

Best wishes, Kevin

Yes, this is helpful. Based on my fully loaded weight, the chart shows that I could be at 60 psi, which is actually below the recommended 65 psi and way below the max 80 psi.

This is probably a topic for a different day, but the calculations show that I’m #700 over my gvwr for the truck but below all of the other limits including tires, axles, etc.

[Bigdog]

Originally Posted by CAG

What does it say on the side of the tire? That will be the max recommended tire pressure.



As mentioned, increasing tire pressure can do a fair amount of damage to the tire if it is over the recommended, including blowing tires out. Ask me, the Chevy dealer rotated tires on my Duramax, over inflated by 20-25 lbs due to a faulty pressure gauge and cost me three tires on a rocky back road. They paid for the new tires and tow.



Want a stiffer ride, install air bags.

The max pressure per the sidewall is 80 psi while the recommended pressure is 65. I have no intention of exceeding 80, but am interested on opinions of the benefits of running somewhere between 65 and 80.

[Kevin Cooper]

Originally Posted by Bigdog

Yes, this is helpful. Based on my fully loaded weight, the chart shows that I could be at 60 psi, which is actually below the recommended 65 psi and way below the max 80 psi.

This is probably a topic for a different day, but the calculations show that I’m #700 over my gvwr for the truck but below all of the other limits including tires, axles, etc.

So, you are saying you have too much weight in the front of your RV.
The chart you looked at from Michelin tells you what pressure you should be running in their tire with that weight on it. Now you want opinions from others because you want to run higher pressure? Hmmmmm. Expert information vs opinion of others that probably do not have your tire or weight exactly the same?
I’m at a loss!

[CAG]

recommended pressure is 65

Recommended by whom? There are two places to see what the tire pressure should be or the max is. On the door post of the vehicle and on the sidewall of the tire.



As Kevin says, you are not going to get expert advice here and I will be the last one to suggest that you run overweight or over pressure.



Your vehicle is not a F-350 therefore those pressure are moot. Go by what your vehicle suggests and make an effort to get the overweight issue corrected.

[CAG]

Short answer is anything up to the 80 on the sidewall is fair game. You need to watch tire wear to see if it is too much. Worn center is a sign of over pressure.

[Bigdog]

Thanks again for your help today. I wasn’t familiar with the tire chart and didn’t realize that I could actually run these at a lower pressure than what is recommended.

My initial expectation was that a needed to be somewhere between recommended and max values.

[Kevin Cooper]

Originally Posted by Bigdog

Thanks again for your help today. I wasn’t familiar with the tire chart and didn’t realize that I could actually run these at a lower pressure than what is recommended.

My initial expectation was that a needed to be somewhere between recommended and max values.

I would have assumed that as well! But if these tires are not exactly what came from the factory, the pressure numbers can change.

[Bigdog]

Originally Posted by CAG

Recommended by whom? There are two places to see what the tire pressure should be or the max is. On the door post of the vehicle and on the sidewall of the tire.

Sorry if I used the wrong terminology. What I’m calling the recommended pressure is from the door post (65). The max per the sidewall is 80.

Total weight on the rear axle is just under 6,000. Rear axle weight rating in 6,340 per the door post. Tire ratings are 3,750 each at max psi per the sidewall and 3,195 each at 65 recommended psi per the tire chart.

[Bigdog]

Originally Posted by Kevin Cooper

I would have assumed that as well! But if these tires are not exactly what came from the factory, the pressure numbers can change.

The tires are the originals with 22k miles.

My next challenge is to understand how the gvwr is calculated and how I can be over that but nothing else. It seems that the total doesn’t equal the sum of the parts.

[Kevin Cooper]

Originally Posted by Bigdog

The tires are the originals with 22k miles.

My next challenge is to understand how the gvwr is calculated and how I can be over that but nothing else. It seems that the total doesn’t equal the sum of the parts.

I have a class a with 19.5” wheels. My tires are 6500 pound rated six tires are good for 39000 pounds. The rv has gvrw of 18000 pounds. Some other class A’s with same tires and wheels have 24000 gvrw. Why? While under the coach the other day, I saw the difference. The springs in the rear have 18K stamped on them. So, the difference is suspension. Pretty sure that is the only difference between 3/4 and 1 ton trucks.
The point is, your truck is rated for front, rear, and combined weight. You should not exceed any of the numbers. Many 3/4 ton truck owners find they are towing more than their truck is rated for and that they should have 1 ton minimum.

[Bigdog]

Originally Posted by Kevin Cooper

I have a class a with 19.5” wheels. My tires are 6500 pound rated six tires are good for 39000 pounds. The rv has gvrw of 18000 pounds. Some other class A’s with same tires and wheels have 24000 gvrw. Why? While under the coach the other day, I saw the difference. The springs in the rear have 18K stamped on them. So, the difference is suspension. Pretty sure that is the only difference between 3/4 and 1 ton trucks.
The point is, your truck is rated for front, rear, and combined weight. You should not exceed any of the numbers. Many 3/4 ton truck owners find they are towing more than their truck is rated for and that they should have 1 ton minimum.

Yes, that’s another interesting topic. These trucks are virtually identical, yet the gcwr/payload goes up by 1,500 lbs on the 350. In my case, the only differences are the recommended rear tire pressure and a single leaf spring in the rear pack.

Through 2019, adding the high capacity tow package actually lowered the payload as it did not impact the gvwr while the added components increased the vehicle weight.

In 2020, Ford rectified this a bit by increasing the gcwr to 10,800 for 250s equipped with the tow package.