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BurbMan's avatar
BurbMan
Explorer II
Feb 02, 2022

TPMS: What's the latest?

I installed a Dill TPMS on my TT when I upgraded to LT tires about 10 years ago. The system uses special metal valve stems with internal sensors, and at the time, the internal sensors were best for reporting both temp and pressure.
Looking at a TPMS system for the new 5er and I see now on Amazon that there are a wide variety of systems with external valve-cap sensors...anybody have any experience with any of these? How accurate is the tire temp using an external sensor?
  • CabinetmakerII wrote:
    I have 14 tires on the ground. I have a dually, 5th wheel, and a cargo trailer in tow. I LOVE my TST 507 TPMS. My biggest issue so far was repositioning the caps after I had my tires rotated. Particularly on the inside dual tires.


    Why the need for sensors on truck as it should be on them from factory and either can set dash to watch them or just let it tell you something's going on?
  • BB_TX wrote:
    I had the TST507 with screw on sensors and wasn’t quite sure how the temperature was derived with those spinning in free air. But I didn’t care about the absolute temperature, only if one was significantly different than the others.
    The free air reduces the sensor temperature and even more so with metal stems. I've measured 20-50 degree differences. This is based on internal sensors with non replacable batteries that were not replaced during the last tire replacement. The psi difference between the 2 systems varied by 1 psi.

    I suspect TST adjusts for the temperature and it's a non issue. One possible clue is that they recommend to not change the maximum axle temperature while setting up the initial high and low axle psi values. They don't state the reason for this recommendation.
  • I have 14 tires on the ground. I have a dually, 5th wheel, and a cargo trailer in tow. I LOVE my TST 507 TPMS. My biggest issue so far was repositioning the caps after I had my tires rotated. Particularly on the inside dual tires.
  • 2oldman wrote:
    The first thing you'll want to do is remove the anti-theft device from the sensor. It makes it a real pita to put air in the tire.
    I use the 507 cap sensor due to it's lighter weight and it does have to be removed to add air. Mine use a simple nut to tighten as the anti-theft aspect and are easy to tighten/loosen with the supplied wrench. The nut remains on the stem.
  • WNYBob wrote:
    If you get external (cap type) make sure you get or have metal valve stems! The extra weight or stress can Crack the stems.
    Don't ask how I know.


    Good Point about Metal stems... I already had metal valve stems so it was a non issue for me..
  • I had the TST507 with screw on sensors and wasn’t quite sure how the temperature was derived with those spinning in free air. But I didn’t care about the absolute temperature, only if one was significantly different than the others.
  • I've been very satisfied with my EEZRV monitor. No repeater required (but is available if needed), it picks up pressure from all the tires on my 28 ft Class C (including the spare) without a repeater. It's easy to set high/low pressure and temperature warnings.

    https://eezrvproducts.com/

    Batteries in the sensors last me around 18 months. I just use the regular cap style sensors, but flow-thru sensors are available so you can fill the tire without removing the sensor.

    I doubt the temperature is super accurate at reflecting the real temperature of the tire itself (since it's sensing it from the end of the valve stem), but you can tell if one tire is running hotter than the others.
  • The first thing you'll want to do is remove the anti-theft device from the sensor. It makes it a real pita to put air in the tire.
  • If you get external (cap type) make sure you get or have metal valve stems! The extra weight or stress can Crack the stems.
    Don't ask how I know.