mine is off 3 lbs in all for tires.

 

TPMS sensors by design are extremely accurate while manual tire pressure gauges even expensive ones are generally off. Since you checked it with two separate gauges hopefully of good quality I would say the vehicle is doing something on the display. I sell TPMS tools & sensors, I have checked my sensors hundreds of times during demos & mine are accurate to the Evic within .3 lb. I would recheck the pressure with a high quality gauge & see if the readings are different. The other option if your really curious is to check the sensors with a quality TPMS tool like the Bartec, by reading the sensor at the wheel you will have the exact pressure reading of the sensors before the info is sent to the module. Most every major tire chain has a Bartec 400 & it takes less than 5 minutes to check.

 

I am about to put a set of after market 22's on my truck and I need some TPMS sensors. What am I looking for as in price and where to buy? Do they just set in the wheels?

 

Also as a side note, the tread act as its written states that the TPMS warning light will illuminate if the tire is 25% low which is why the sensors need to be so accurate. The tread act is the reason we have TPMS in the first place FWIW.

 

i use a truck tire gauge
places like Orielly's, SEARS, Home Depot, Lowes, Advanced Auto, etc carry them
they are pretty darn accurate
i personally like the MILTON brand

http://www.oreillyauto.com/site/c/detail/MII0/S927/N0176.oap?ck=Search_N0176_-1_-1&pt=N0176

 

I rep Milton too so thanks for supporting us! Yes, both Milton & Tru Flate are quality gages with excellent accuracy. I would recommend either over the usual gages you pick up at most auto part stores.

 

Can Cold Affect Accuracy

When I started my '09 Ram a couple nights ago my "Low Tire Pressure" message came on. It was 26 degrees out and the coldest it's been since buying the truck in August.
I checked the pressure when I got home and they ranged from 34 psi to 30 psi. The next morning I equalized the tires at 35 psi and drove it several miles, parked it, and when I restarted it the warning was gone and has not returned.
Can cold affect the sensors?

 

Cold will not affect the sensors unless it is extreme cold like -30. The tires will have lower psi when cold than hot. If you checked them as soon as you got home from driving them expect them to be about 2-3lbs higher in the winter when they are hot vs. cold. In the Summer you can see 4-6psi difference. So in other words when you started the truck the tires were cold so the TPMS light went on, when you came home even the tires registering 30psi hot are still too low. The system will reset itself when the tires are set to the tire placard spec. The sensors are reading whenever the wheel is in motion & sends the data constantly for the module to read.

 

Cold will not affect the sensors unless it is extreme cold like -30.

What happens at -30? I have already seen that temp this year. Are they less accurate?

 

Two digital Accutire Tire Pressure Gaugesrecently topped Consumer Reports' rating as most accurate.

I have the one in the link below and nine times out of ten, it's dead-on with the cluster TPMS readout.

http://www.accutiregauge.com/progra...grammable-digital-tire-gauge/accutire-ms-4350b-programmable-digital-tire-gauge/