Talking Trucks Tuesday: Tired of the Pressure

IMG_3614 TTT II

By G. R. Whale

Of all consumer motor-vehicles, pickup trucks are the most likely to be worked to their limits.

And except for a few commercial vans, pickups generally have the widest variances in weight. Some heavy-duties are capable of carrying their own weight, which makes it difficult to figure out exactly what tire pressures are correct, which varies with load and speed.

After the federal government mandated tire pressure monitoring systems in 2007, we noticed most owner's manuals dropped sections about tire pressure adjustments for speed and load. These sections included a listing of worst-case, fastest conditions, meaning maximum loads and highest speeds. That's a disservice for consumers.

Today's pickups come with tire pressures listed on the sidewall of the tires; these pressures are for a full load. So, if your three-quarter ton isn't carrying 2,000 or 3,000 pounds, you get an extremely stiff ride and excessive rear tire wear. However, if you air down the tires to improve ride quality, the tire pressure monitoring system will turn on a warning light, even if the display shows nothing is lower than the amount of air you put in your tires. You're also likely to get an annoying chime each time you start your truck.

I drive and test pickups with the tire pressure matched to the load I'm carrying (or not carrying) — not what the tire pressure monitoring system thinks is correct — and I haven't had a tire failure in 40 years.

What do you do about tire pressure? Do you adjust your tires to specific conditions or merely run them at max pressures as stated on the driver's door sticker or the tire sidewall? Let us know in the comment section below.

Cars.com graphic by Paul Dolan; Cars.com image by Evan Sears

 

Comments

A perfect illustration of the grief we endure when Washington bureaucrats intrude into the realm of private lives and private decisions.

I confess to appreciating the tire pressure tech because for me it's convenient. However, the author describes a classic annoyance, not much different than the dopey seat belt chimes.

Given the opportunity I bet many buyers would love to hit delete on quite a few of these nannies in today's cars/trucks.

I run my DRW at 70 in the front and 80 in the rears and leave it alone.

But I am usually hauling or towing a heavy load.

I wish the author knew that the pressure on the sidewall does not relate to that truck at all, but is the maximum that tire can be inflated to regardless of what it's mounted on. The door jamb has the correct pressure for that vehicle, not the tire. This is one of the most basic misunderstandings you see tire websites try to correct.

I love tire pressure monitoring systems and look forward to having them on my next truck.

Another thing to consider is, when you go up several tire sizes from stock, the door sticker/manual no longer show the correct value for inflation. The bigger tire (assuming you stuck with stock rim size) has more internal volume and requires less PSI to hold the same amount of weight.

I ran 285 series tires on my old HD Sierra (16% larger tire than the 245 series tires that came stock on those trucks) and the ride was significantly more harsh if I aired them all the way up to the factory inflation values.

I did a simple test where you draw a line of chalk across the tread of the tire and observe how it wears off (more worn in the middle = overinflated, more worn on the shoulder = underinflated). That got me to about 40 PSI in the front tires (factory label called for 45-50) and 35 in the rear when unloaded (factory label called for something like 60-80 when loaded if I remember right). I ended up just running 45 all around after that test just so I wasnt having to air up every time I wanted to put anything in the bed, but it made a huge difference in tire wear and ride quality from making those little adjustments.

Now that I drive a halfton, I havent changed the tires out yet so I just run the factory recommendations and no complaints so far.

I run psi according to load. Same on my 5th wheel. I have E rated tires on the 5er. since it came with d rated tires I only need to inflate the E's to the d psi.
Same on my truck. It came with some 245/70/17's. I upped to 275/65/18,s. No need to run them at a higher psi. I run what the door sticker says.
So many misinformed people have no clue about what psi to run.

I have a mid-size truck and went up several sizes to 33 inchers. I do not like the warning light so my rear tires are over inflated for the lack of load I am carrying unless I am going on a hunting trip.. I bought some E-rated tires once, each tire was rated to carry my whole truck, talk about rough riding, but they lasted 80k miles..

I have a mid-size truck and went up several sizes to 33 inchers. I do not like the warning light so my rear tires are over inflated for the lack of load I am carrying unless I am going on a hunting trip.. I bought some E-rated tires once, each tire was rated to carry my whole truck, talk about rough riding, but they lasted 80k miles..

Government is not the problem. Government is the solution.

Since most truck people dont care about towing or what their truck can tow, they wont be worried about pressure in tires either

If you buy a truck that has the capability to meet your needs, why worry about the ride? Just make sure you do your research and buy a pick-up for what you need. If a 1500 series truck will meet all your needs, why would you buy more capability?


People who are not appreciative of the tire pressure monitoring systems can thank Ford for it. Fords handling of the "Exploder" with their Firestone tires installed has led to these tire pressure monitoring systems.
Now for one, I have no issue with TPMS.

You can thank Firestone and their tires for this.

At work, I drive a 2010 RAM 2500. There is a button on the dash, just below the radio, that allows for two different tire pressures without upsetting the TPMS. You run the rear tires at 80psi when loaded or towing, and you can drop pressure to 45psi, or thereabouts, when running empty. Makes for a MUCH better ride when empty, and more control over bumpy roads.

I hear that RAM did away with this system after a year or two because idiots were forgetting to air their tires back up when hauling, having tire failures, and then suing RAM. Blame the lawyers.

Here's an option for bypassing the TPMS.

Get a piece of 4" PVC pipe, about a foot long. Also get end caps to fit it. Put your four TPMS sensors in the pipe...add some filler material like foam or insulation to keep sensors from rattling around.

Drill a hole in one of the end caps and insert a Schrader valve. Glue the end caps onto the pipe. When cured, add 35psi (or whatever your vehicle calls for) air pressure to the pipe via the Schrader valve. Toss the pipe into your back seat, bed, or wire up securely under the truck.

Never worry about the TPMS light on your dash again. Change between dedicated summer and winter wheel sets with impunity. Just be sure to check your tire pressures every now and then, especially when the seasons change...

You can thank Firestone for the crappy tires.

You can thank Ford for the awesome sensors that have a lot of benefits including no more manual gauges, increased mpg, and better insurance rates.


@papajim-- http://www.sexycongress.net/i/f33.jpg

I adjust my tire pressure to the load I will be carrying. Tires are expensive and I want to maximize the miles I get out of them. There are tables available that show how much pressure a given tire size will need to handle a given load. I use this as a starting point. From there, I watch the wear pattern on the tire and adjust the pressure up if warranted.

Max pressure all the way, all the time. Live a little.

Firestone screwed me. I keep my tires at the max psi and check them every month and I had a rear tire blow. I was unloaded too. I made a claim with Firestone and had to send my tire in. I got I letter back saying my tire was under inflated and the would not pay for the damages to the truck. They were the Steetex tires also. I will never buy Firestone tires again.

On my car, a 2015 Sentra SL, I went down from a 205/50 R 17 to a 195/65 R15.

I re-used my tire pressure monitors.

I'm sure somebody will question why I went from a 50 series to a 65, but it's pretty simple that I lost about 6 or 8 pounds per wheel, which equals better gas mileage.

Tire size was supposed to be off by only not even a tenth of an inch, but realistically it is off by almost a quarter of an inch. But, with the bigger tire/wheel combo on there it wasn't reading as many miles is it was covering. So it's more realistic now than what it was before.

Tires are cheaper, more choices, better mileage, and, the 65 series actually has a higher weight rating than the 50 series, I think per tire I can hold maybe about 20 more pounds.

Oh, the ride is better also. I didn't buy a Sentra to be a road race car.

Similar stuff applies to trucks.

@devilsadvocate--I had to put 45 psi in the tires of my truck with a tire monitor system just to get the tire pressure monitor to go off. I usually put 35 to 40 psi in my tires which is what I put in my other truck without a tire pressure monitor.

I run my air pressure for comfort on road. 45/50 psi. 65 psi with the trailer. one pound of air equals five pounds of spring pressure. Have to air down for off road. Sand is about 15 psi. No axle wrap and smooth on the dunes. 15 Ram 2500 Power Wagon.

G. R. Whale and Mark Williams - - -

Thank you for bringing this topic up. It's really very complex, with lots of variables. Here are ten of them:
1) Starting Ambient Temperature;
2) Actual Total Load over/on each tire;
3) Speed and linear acceleration of travel;
4) Cornering or turning needed (radial acceleration);
5) Duration of the trip;
6) Conditions of the road surface (potholes, etc);
7) Weather, e.g., bright hot sun or cold heavy rain;
8) Side Angle the vehicle must endure on the trip;
9) Tire-fill gas (whether Air or Argon or N2);
10) Tire quality, construction, and wear cycle.

So there is a LOT to think about and unfortunately, no one tire pressure setting at the outset can meet all conditions. But by considering what you may be getting into, you may also avoid the "Gee,-the-tire-just-blew-on-me" scenario.

My experience over 40 years with mostly "1/2-ton" trucks has produced four guidelines: CHECK, SLOW, LOOK, and FEEL.
1) CHECK the tire pressure at the outset and CHECK and adjust along the way;
2) SLOW driving, SLOW cornering, and SLOW acceleration are essential (way different from driving an empty truck!);
3) LOOK at where you driving, and LOOK at what your tire "looks like" along the way (too squat?, rim side-wall cracks?);
4) FEEL your tires! At most, they should be warm, but never too hot to touch. Pay attention to your tire's temperature rating, and even use a thermocouple contact or IR thermometer to measure tire surface temperature, at the side wall (which works the hardest).

Rule O' Thumb: I have typically started off with Load-range D tires at about 35 PSI in an empty pickup (for best ride), and gone DOWN for off-road traction (empty); but gone UP in 5 PSI increments for every 500 lbs added load IN THE BACK. I'm sure others have alternative "rules"...

======================

Those that put larger than 22" rims on a 4x4 are really dumb!

Off-roading 101, you need to air down for better traction, you cannot air down much with 20" or greater rims!

Walmart has ASE Certified Tire Technicans where they are fully trained and they told me I CANNOT exceed the air pressure with TMPS sensors cause the sensors will go off and flash on my dash when I exceed the recommended pressure. My truck calls for 35 psi and I installed 10 plys and put 80 psi in and my sensors didn't go off

ON some vehicles, the TPM settings are adjustable.
Correct tire inflation is a 3 step process
1. Weigh each axle (scrap yard, cat scale, whatever) or at least find accurate axle weights.
2. use this formula to calculate how much pressure you actually need: (psi for max load)*(axle weight/(2*max tire load)= approximate correct pressure.
3. Test and adjust- make several chalk lines across the tread and drive the truck mostly straight- edge wear needs more pressure, center wear needs less.

@gms, so what you are saying is GM followed FOrd down the TPMS path?

@gms, so what you are saying is GM followed FOrd down the TPMS path?

Posted by: Nitro | Mar 8, 2017 7:09:06 AM

Nope. I did not say Ford introduced or developed it first.

Firestone recall and legal mandates.

The Firestone recall in the late 1990s (which was linked to more than 100 deaths from rollovers following tire tread-separation), pushed the United States Congress to legislate the TREAD Act. The Act mandated the use of a suitable TPMS technology in all light motor vehicles (under 10,000 pounds), to help alert drivers of under-inflation events. This act affects all light motor vehicles sold after September 1, 2007.

its all very easy, I was told a long time ago to run tires as soft as possible, for the best ride handling mix. Then go out on the hyw and build up some temperature. Then check the pres. if the tire have gained more than 5 lbs of air, they were too soft! Loaded its the same way, go out as soft as prudent, then after some miles check them again, once again if they have gained more than say 5 lbs, they were too soft to begin with. After a while you get to know what is best for your vehicle. I will say this, having the new systems built it does make it a lot easier to check the pres. as you can now do it as you roll along. I have found using a gauge now, is not as mandatory as before, now I just count a number of seconds as I let air out, get close with the gauge, then walk up and look at the dashboard to see what the system is telling me!

@Sandman--I still use a tire gauge but I use the round dial type which I have found to be more accurate. Once a month I check all my vehicles tires when they have not been driven. I have a portable air compressor, it is not a big deal to add additional air into tires. Usually I put the maximum tire pressure that is listed on the side wall of the tire except for my Isuzu which has the tire pressure monitors that go off unless you add an extra 5 lbs of pressure above the maximum. I have the tire caps on all my vehicles that warn if tire pressure is low--green is good, yellow is a warning, and red is the tire is under inflated and needs air. The air compressor that I use has a tank on it and fills the tires fast with little effort.

@Jeff S

We admire the attention you give this but too much pressure can be just as dangerous as too little. Maybe worse. An overinflated tire over a period of time becomes fatigued in ways that are not readily visible.

I suggest that this might be simplistic, but just check your tires in the morning when they're cold and watch for signs of underinflation.

During the hot hours of the day a tire that's too hard is pretty easy to spot, in my experience. Radials and bias plys need a different approach of course.

@papa jim-I always check my tires when they are cold. The only tires that I have over inflated are the ones on the Isuzu because the tire pressure monitor will come on if I don't. Maybe I need to replace the tire pressure monitor system, but I will see. Usually in warm weather I don't have to add any air. The tire caps with the low pressure indicator work better than the monitor and are much less expensive but the monitors are now required on all vehicles. I agree with one of the comments above that said we have these monitors because of the Explorers and the Firestone tires which both could have been avoided it the tire pressure was properly maintained. I have always maintained my tire pressure and keep tire gauges in every vehicle along with jumper cables and a portable air compressor. A lot of problems with vehicles can be avoided by proper maintenance and using common sense, but unfortunately most people lack common sense.

Unless you are running the exact same tire size, load rating, and even manufacturer, the door jam sticker is a guide.
My truck has one size on the sticker, but came with LT load range C ties of a different size. It was a factory option package, not a dealer add-on. Discount Tire has never been able to figure it out, but suffice to say the chalk trick works and is the most reliable.
As far as running the tires at the max cold pressure listed on the sidewall-this will give a more firm ride and may accelerate middle tread wear, BUT, the majority of heat comes from sidewall flex. Starting at the max cold PSI reduces sidewall flex and the radical temp deltas.
Running D or E load LT tires will dramatically impact ride and handling, but load carrying is vastly improved.
I've wheeled around 10,000 miles on load range Es and they are great. Better on and off road, more puncture resistance, with better sidewall strength at low pressures.

@James--Thanks for sharing. Good information to know.

I got sick and tired of multiple flats with the stock Wrangler SR-A's. I went with 10 ply "E" rated tires and haven't had a flat. The truck is more stable under load running the factory recommended tire pressures.

To those who are complaining about TPMS, you can thank all of the idiots out there who never check their tire pressure.

You can reset the TPMS on Ford pickups. I assume that there is a way to do the same for other brands.



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