Anybody know what the threshold is (lower limit) of tire pressures on a stock super duty? I'm interested to learn how low I can go w/o triggering the TPMS warning. My sticker tells me I'll have 3475 pounds of payload available to me, so it'll ride like crap unladen.

Putting a battery tender on the battery and checking tire pressures is one of the first couple things I do when a new vehicle comes home. Assuming things go correctly w/ my F250 purchase in the coming days, what can I air the tires down to and not trigger the light?

 

On my '17 I think its 50 psi or below, however I had a guy use Forscan and he lowered it to 40 psi. With Forscan you can also remove it all together. I would assume the '23 software is the same as far as TPMS is concerned.

 

Don't know where it triggers but I used FORScan to set mine to 30psi. I always run 40-45psi so being set at 30 i know if it triggers then I may actually have a low tire and not just the air fluctuating a couple PSI

 

I’ve found it will alarm around 15psi below the set pressure. If you want it to alarm at 40psi I recommend setting it at 55. If it’s set at 30 it might not alarm until the tire is below 20 and you could do some real damage running on an under inflated tire.

If you change the settings, or just want to find out where it actually alarms just drop the pressure a bit at a time until you get the warning.

 

My rear wheels were stickered at 80, and the TPMS light came on at 62. I lowered the warning to 40 with Forscan, and actually run them at 52-54 unless towing. I want the warning to be for a real tire problem, not just an annoyance.

 

I check my tires religiously and don't rely much on the TPMS anyways, it was more of just a fail safe. Before I lowered it, it would trigger if the psi dropped due to cold weather. So I made sure it wouldn't come back on unless it was really low. I no longer have that truck and my 450 doesn't have TPMS enabled and have no desire to add it even though many on here have done so.

 

Ok, not the same as folks responding so far but info for those with 2023 350 dually wondering about the same issues:

My sensors are incredibly accurate versus a hand gauge (Milton service station).

Inflation Sticker on door frame
Front 75
Rear 65

Zero issues when loaded heavy with tires inflated to:
Front 80 (max)
Rear 70

Running empty
Front down to 60 no issues (I have 7.3- this may be a bit mushy with heavier diesel).
Rear 55 OK but note below
Rears running at 55 has no issues but if outside air temp drops enough overnight, as it tends to do this time of year, and screen shows 54 (confirmed with Miller) alarm screen comes up upon every start thereafter, and the orange inflation indicator on dash stays on when running. Next morning temps back up and light comes on indicating cold inflation is 55 but will not stop despite several restarts and during noon sun days driving at 59 psi. Ditto if outside morning air next day is high enough to indicate 59 (confirmed with Miller). Orange indicator light stays on at 55 and 59. Only way to get either/both back to “ok/off,” other than Fortran, is to inflate back up to 60 psi in the morning BEFORE first ignition cycle. Inflate to 60, cycle ignition. Alarms gone. Deflate to 55, alarms stay off until hit 54 again. MAYBE hard or heavy driving could raise psi to 60 from 54, and that would similarly reset the alarm screen and indicator light, but have not tried it.

My empty 2023 7.3 350 dually rides best at 60 front/50 rear. I have 5th wheel prep. When “empty,” I almost always have 80# torneau cover and 125# air hitch in the bed. Maybe 25# of tools under the rear seat.

 

The placard on the F250 in question reads 60 front / 65 rear.

 

I want to say they trip at 15 or 20% below the value on your door sticker or something to that effect.

 

I have the same recommended PSI on label. My low PSI warning has only popped up once, that tire was 20% below sticker PSI.

 

I’ll probably weigh the truck and run it over the CAT scales just so I have a baseline for the axle weights (after the tonneau and bedliner, etc.). I’ll try 15% off the back and 10% off the front and see how it goes.

 

20 F350 7.3, sticker and original setting was 60/80. I could run 50/65 and be safe as long as the temp didn't drop too much. Once the TPMS warning starts, you damn near have to bring them all the way up to get it to shut off. Switched tires and wanted to consistently run 50 all around. Simple Forscan adjustment to put them all at 40 and problem solved.

Erik

 

I am really ignorant as far as computers and Forscan go,
Will dealers lower the TPMS threshold?

 

I doubt it, it's federally mandated with a trigger point based on the vehicle manufacturers suggested cold PSI.

 

Dealer will not adjust it and in fact when I asked the service manager he blatantly lied to me and said it couldn't be done.