Jaryd21

Hey guys I am just trying to figure something out here. If you buy new wheels for your car and it requires a different (higher) psi in the tire such as 35psi stock and 50psi new wheels does this affect the TPMS. Thanks

Bert

First, you are confusing the pressure rating of the tire, with the recommended pressure that you should run in the tire. All tires have a fairly high maximum pressure, like 50 psi, but that does not mean you should run them that high. You should generally run the pressure that is shown in the door jam label/sticker, like 32 psi for most Mustangs.

Next, the TPMS -- Tire Pressure Monitoring System . . . this is a sensor in the tire that tells when the pressure is too low, based on what is "normal" for the car. in my 2010 Mustang, it will set off the warning light at about 25 psi. This will not change when you change the tires -- 25 psi will still be "too low" and the TPMS will still turn on the warning light at that pressure.

When you buy new wheels, you do need to make sure that you get the right TPMS sensors. The sensors need to be compatible with your car; if you order them for the correct make model and year of the car, then they should work. In the Mustang, the TPMS systems changed over the years:
2009 and earlier
2010-2014
2015+

JimB.

For some reason I thought when I did my swap. New tires, wheels and TPS it had me set the tires at the desired running pressure before programming the new sensors.

Bert

I am not sure how the system determines what pressure to flag the warning light. It might use some percentage of the pressure that was in the tires when you programmed/calibrated the sensors; for example of you calibrate them at 30 psi, then 33% pressure loss would be 20 psi and that's when it would throw the warning.

If that is the case, the the OP definitely would NOT want to calibrate the sensors at 50 psi, because then it would be throwing the warning at 33 psi or something like that.

anyway, back to the original point -- new tires do NOT require higher pressure; if you use the right pressure (32 or so) then this won't be an issue