I was a bit confused and puzzled by the fact that from the factory my stock tires (285/60R20 Firestone A/Ts) came with over 80 PSI in the tires, while the sticker on the door states they should be at 65 psi. Is this a common occurrence on these trucks? Do I lower them down?
No different than any 3/4ton trucks for the last 10 years or so since the NHTSA stepped in and mandated TPMS on light duty vehicles, resulting in 3/4T pickups getting mandated to be sold and monitored to the high pressure rating of E load rated tires.
You can run whatever pressure you want. TPMS low pressure light will come on at pressures much greater than needed for an empty truck (I forget the threshold but it's like 65-70 psi in the rear triggers the idiot light). Won't hurt anything, or you can program it out with aftermarket software (presume still can on '19 models).
Usta be able to program it out with OE software and lower the pressure thresholds, but that became "illegal" in about 2015 and dealer software no longer had that functionality.
So 3 options.
1. Keep pressure too high for an empty truck and keep the monitor happy while spilling your coffee and loosening your molars over potholes.
2. Lower pressure to the proper pressure for the load and keep yer teeth in tact at the expense of the light.
3. Adjust the TPMS thresholds at a $ cost.
Proper pressure for an empty/lightly loaded srw diesel pickup with that size or similar size tires is 60psi +/- front and 40 psi +/- rear.
Same 4th gen tires and wheels on my 07 Mega.
Summer: 55-60F/40-45R
Winter: 50F/30-40R for better traction. only air down that low in the rear if I get into some real snow. Wouldn't drive around indefinitely like that.
4000lb+ truck camper in the bed: 65F/80R
From internet research and trying it myself, the factory TPMS is set for 60PSI, with the light triggering at 48 PSI (a 20% threshold).
At 60 PSI, the outer edges of my my new non factory E load rear tires are clean and the ride is lets say firm.
Not sure how the same E load factory Firestone's at 60PSI didn't wear or ride the same.:confused013: The suspicious nature in me wonders if the factory tires are really D load rated with 60PSI to keep the load capability...?
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