I was just at the dealer Friday getting an oil change they claimed they couldn't change the threshold anyway. I pushed that I had read you can and I got the attitude how dare I question him look. I said I don't want to run 80PSI in my rears all the time and he told me it would wear out the tires. I said I didn't care its a daily Highway runner. What's the lowest I can run before the warning light comes on for front and rear? 22 F350 SRW Reg Cab.

 

Can't change the threshold is a lie, plain and simple. Wont change it would be the honest answer. I have changed my TPMS thresholds because they are ridiculous. Mine are set to 40 psi front and 35 psi rear and I generally run 50/42 in the summer unloaded and 60/52 in the winter for the plow and ballast I run. The old "wear out the tires" argument is 100% bunk, my duratracs went 50k miles and were never inflated to the recommended pressures. I dropped the pressures before I left the dealer with my new truck.

 

That shouldn't be a surprise, the tpms is federally mandated and is supposed to alert within a specific % from manufacturer recommended pressure. It could be a liability for the dealership to change that threshold bellow that required set point. So yeah, it's not can't, but won't. Also, if you do lower the psi expect the dealer to increase it during service visits unless you specifically tell them not to.

You can lower the threshold yourself with forscan, otherwise the lowest you can go without the alert popping up is about 20% lower than what the sticker says.

 

I get by by running my rears at 65 pounds. The fronts I run about the same. If it gets cold and the pressure drops, the rears will go off at much less than 65 pounds. I detest the dealer set perimeters, but I don’t have forescan , so I guess I will have to live with them. The fallacy of the TPM perimeters is that unloaded The front needs more pressure than the rear.

 

I don't have a computer able to run forscan, so I just accept the TPMS dash warning light always on. The good thing about running tire pressure below the TPMS warning threshold is that the tire pressure screen always appears with vehicle start up. I like looking at my tire pressures so the tire pressure screen upon start up saves me a step..

 

On my truck the TPMS light comes on when the tires get to 20 percent less than the recommended inflation on the door jam tag. This number fluctuates with different people? It’s a reference point to start at. On mine it’s not low enough to get the tires at a reasonable inflation so I just deal with the light. One day I’ll get forscan and fix it.

 

That shouldn't be a surprise, the tpms is federally mandated and is supposed to alert within a specific % from manufacturer recommended pressure. It could be a liability for the dealership to change that threshold bellow that required set point. So yeah, it's not can't, but won't. Also, if you do lower the psi expect the dealer to increase it during service visits unless you specifically tell them not to.

You can lower the threshold yourself with forscan, otherwise the lowest you can go without the alert popping up is about 20% lower than what the sticker says.


I thought about that its a liability for them at the time. Should have just explained that to me instead of lying just adds to the already untrustworthiness people feel with dealing with them. It was my first experience with them also first service for the truck. it didn't leave a good first impression.

 

But thanks to the good people here for helping out.

 

And depending on who does your tire work.... I bought my last set from the new Discount Tire in town. They do free rotates but inflate the tires to the sticker numbers each time, 70/80 psi in my case because it is company policy to do so.

Then I sit in their parking lot and adjust them with my gauge. I have this dream where they realize this game is a waste of time and set them where I want them but, it is just a dream...

 

In my unscientific opinion, having max psi set for the truck rear tires when traveling in an empty truck with no load and not towing is its own liability on wet surface roads due to the decreased tire contact patch. It also seems to me that max psi in empty truck rear tires also increases the tire sidewall stiffness and the truck rear end is more likely to jitter skip on rough road surface turns.

 

A tread depth guage to adjust air pressure? Wut?

 

It doesn't.

 

Completely agree but what Ford was sued for years ago was underinflated tires blowing. That is the reason TPMS exist in the first place... Government saving us from ourselves by dumbing it WAAAAAAAY down.

It is really easy to weigh your vehicle and consult inflation charts to determine appropriate pressures for the load on the tires. Running 65 psi or mare in the rear tires of an empty truck IS a bad idea but most people are too lazy to take the time to adjust pressures. Much easier to obey a sticker they don't really understand and just look at a dash display with the push of a button. That is the world we live in... You will even find people who insist the sticker settings are their gospel and their tires last 200k miles because of it.

According the inflation chart for my tires, at 42 psi I have 1000 lbs capacity above the empty weight of the truck on the rear axle. Running 65 psi would give me 3000 lbs load capacity, way more pressure than an empty truck needs. My setting of 50 psi front puts me about 500 lbs over what the front end weighs, I air up during plow season for the additional load. My last set of 285/75-18 duratracs lasted 50k miles because I keep them properly inflated and rotated. It isn't rocket science.

Oh and this F350 was plenty comfortable on a 5500 mile empty road trip last spring.

 

Works in theory, not real practical... He is talking about monitoring variations in tread depth and adjusting pressure to compensate.

In practice, the centers of the rear tires wear faster and the edges of the front tires wear faster. Rotating balances these patterns out. Mostly on mine the fronts get a little rounded and I move them to the back to get them squared back up. If you can't see when this is necessary by eye, the depth gauge can help.

I still think the best is setting pressure for load using accepted load carrying charts and the actual weight on the trucks axles.

 

All that inflating and deflating with algebra figuring gets you the same amount of tread life as I get and I carry over 1500# all the time. I see 50k mile life all the time with my tires with 65psi front and rear.
I even had one set of Les Schwab brand tire go 62k miles but those were pricey tires.

Tire rotation is important for the longest possible life. Especially for someone like yourself that is pulling trailers and plowing.