I've got a new to me 2016 F350 Lariat CC with the optional 20" wheels and 275/65/20 Michelin tires. It has a 6.2 gas engine and single rear wheels. I took it to the dealership for an oil change and once over to check things out. They set the tires at 65 front and 80 rear and I think I've got a loose filling from the ride home. How much change will set a TPMS light? What do you folks with a similar truck run for pressures for normal commuting? Thanks!

 

If you check the door tag for your tires, I believe you will find those are the recommended pressures on an SRW. You can probably get away with 10 psi. If yo uahve a laptop, an OBDII adapter and FORScan, you can change the psi points for warning you.

FORScan 2016 Super Duty - Google Sheets

 

Anybody near central Massachusetts that can reset this parameter for me? Dealer service department says he is not able to change settings.

 

I think quite a few of us just air down and when the warning comes on just hit the "okay" button and ignore the flashing light on the bottom right hand corner of the screen.

Steve

 

I run the same tire on my 2019 Power Stroke at 60 PSI all around while unloaded. That gives a good ride while still providing good steering response.

 

A couple things to keep in mind:

1. Manufacturer tire recommendations apply to stock size tires for that specific vehicle and, in the case of Ford trucks, the recommended PSI is so that the truck and axles can be fully to the GVWR and GAWR.
2. There is some give in the TPMS system. Even if the tire is 25% low, it may not trigger the warning lights. Case in point, my truck has a 65 PSI recommendation and at 50 PSI, no warnings came on but my stereo showed the exact PSI at that.

For a better ride, its absolutely OK to air down as long as the tires are still able to carry the weight on that axle. It takes a bit a math and a trip to the scale; however, a more comfortable ride will be the end product.

Here is the Load & Inflation Table Application Guide you can use to determine a tire's load rating at a given size and PSI.

In my case, the truck calls for 65 PSI on the 275/70r18 tires front and rear. This gives me a load rating of 3195 per tire or 6390 per axle. I bought new tires & wheels that were 295/60r20 and to keep the same rating, I would run at 62 PSI. Knowing that the front axle has a max load of no more than 5000 lbs when the truck is fully loaded, the new tires can still run safely at 45 PSI and support 2530 per tire or 5060 for the axle. Weighing the rear, unloaded is about 3800 lbs and can take even less PSI. For me, a happy medium is running the tires at 50 PSI on all corners. This gives a load rating of 2755 per tire or 5510 per axle. In the end, my truck rides better on the 20" wheels & tires with 50 PSI than the stock 18's at 65 PSI and still has the tires still have the ability to safely carry the truck while fully loaded. This is all with the TPMS system functioning and still not giving any warnings.

 

Thanks all for the help. I aired the rears up to 70 to get the light to go off. I backed them down to 68 and still no light. I may try a bit more when I have time to mess with it. The fronts maynget dropped a bit too. The ride is ok but if I can tweek it a bit better I'll do what I can.

 

Get an OBDlink EX and use Forscan to turn off the TMPS altogether. That's what I've done and I've had no issues whatsoever.