TRD OR ideal highway tire pressure

Do you think that the engineers who will do anything to save a penny per truck and are trying everything possible to bring the Corporate Average Fuel Economy up a percentage point wouldn’t think to tell everyone to raise their tire pressures by 10lbs? What does it do for traction during a panic stop situation or swerving to avoid debris/animals? Not saying I know the answer, but if it’s that easy to raise the mpg, why haven’t they done it?

 

If the carmaker writes that 30 psi, then your tires are safe with evenly loaded GAWR'S upto max technical carspeed mostly, or upto 160kmph/99mph.

Had myself written by a man from a tirecompany , that you can go much higher then minimum calculated pressure for safety, before centrewear happens.

Tesla prescribes sometimes 42 psi, while probably for safety 30 to 35 psi is enaugh, and that is only to give the battery a higher actiradius. Only sometimes you read on Teslaforum about centrewear.

But a bit to low psi, gives already wearing of both sides of tire.
For acceptable comfort and gripp, i once determined by reactions, that if you have less then 85% of the load , for wich the pressure is calculated for 99mph, that then comfort and gripp gets unacceptable, but on highways the border is lower.
Example: pressure calculated for 99mph for 1000. Then if real weight is below 850, comfort gets unacceptable, below 700 probably centrewear. Over 1200 mayby sides- wear.

Rolling resistence makes about 20 to 25% of total energy use when driving about 50mph.
40 against 30 psi gives 30/40 times surface on the ground , and about 3/4 squaire = 0,5625 x deflection , so if lineair relation 0.5625 times the heatproduction at same speed . So asuming 50mph 25% x 0.5625=0.1406, make it 15% . So fuel consumption goes to 90% with 40 against 30. This is instead of 100/ 17= 5.88gallon / 100miles to 90% = 5.294g/ 100m= 18.88m/gallon. Dont burn me down on the many digits , it is yust an indication.

 

35F 32R

 

The number on the door panel is around 30 PSI and that is for best ride UNLOADED. The number stamped on most P rated tires is about 44 PSI and that is the number you should be using if loading your truck to near the max GVWR.

Anywhere in between is acceptable. When I had P rated tires I always ran 38-40 PSI in my tires because I often carried loads in the bed. Carrying loads with under inflated 30 PSI tires is dangerous. By keeping my tires near the upper end of acceptable air pressure meant I could safely load the truck without having to take the time to air them up every time I had to carry a load in the truck. It also improved fuel mileage by 1-2 mpg. I find the ride suits me just fine at that level.

I've been able to get 55,000-60,000 miles out of every set of tires I've had on the Tacoma at that tire pressure. And I'm not the type to try to squeeze every mile possible out of tires. A lot of people would have driven them another 5000 miles.

Of course I've been running E rated tires for several years now and that is another thread.

 

I had Keller Safari \ Goodyear DOT 11/2014 E load tires \80PSI as max marked, and used them for 40,000 ,miles, try them different PSI but happy with 40-42 psi all the time, 45- loaded; I was surprise they still have life when I change them but I learne d the lesson OFF ROAD TIRES ARE just that .... good look but not nice to Highways, I jumped into a $85 deal per tire with Cooper Evolution HT.\DOT 05/2020.... what a difference !!!! is like super smooth ride.....read the tech of this tire, made in USA and specs close to the Michelin Defender quality for half of price...... anyway , I decided to participate in this Q and found this on internet,,,,

How to Calculate Correct Tire Pressure

1. Read the manufacturer's maximum inflation pressure on the side of the tire.
2. Calculate 10 percent of this amount. If, for example, the maximum is 40 psi, then 10 percent of 40 is 4. Subtract the 10 percent value from the maximum psi value. So, 40 - 4 = 36. Use 36 psi in your tires.

 

There are all kind of theories and ideas, but I like to see things for myself. If you are of that same mindset and want to see what a difference air pressure makes, hop on to your old bike. Spin a lap at 10 psi then bump them up to 50 (or more if it will handle it) and spin another lap. You will see how much easier it goes with more air. The same thing happens with your truck. More air = less energy. You will also notice that your soft comfortable ride gets more harsh. Everything is a compromise.

 

Perfect

 

30 on my 19 OR is perfectly fine.

 

How fast are you typically driving? That will affect your MPG more than a pound or three of tire pressure.

 

I always run vehicle manufacturer specified pressure on stock tires. They did the research to determine it. POTUS Obama a few years ago stated by increasing our tire pressures we could save gas. Must be right.

 

Absolutely don't use that calculation. My E load ST Maxx wear best just north of 40psi hot. Their max pressure is 80psi. I would not want to run them at 72psi. My psi is based on my real world wear observation. I found a chalk test showed a little lower and it rode softer as well, but produced abnormal shoulder wear.

 

+1

I had a similar situation on my bike with otherwise killer tires. I had severe cupping at the factory pressures 33F / 37R. Trying 34F / 38R helped, but 35F / 39R was the magic bullet. Cupping completely gone and I decreased the wear by about 50%.

The shit matters.

 

Dealer set mine to 35 this week. That's too high in my experience... won't allow for a proper footprint and will wear the center prematurely.

With my pickups I also typically run lower pressures in my rear tires, since most of my miles I'm unloaded. When I'm headed camping or towing, I air them up. This was especially necessary in the diesel trucks I've owned since the motor weighed so much.