Topic: TPMS heat sensor on dually behind exhaust  (Read 273 times) previous topic - next topic

WIth the dually tires I was uncomfortable not knowing the pressure of the inner back tires, so the solution was a TPMS that was already in the box in back of a 2016 Unity I bought 2 years ago.  After installing it (and now knowing why the previous owner hadn't gotten around to doing it) I noticed that the pressure readings do increase as expected especially with highway travel.  However,, I also noticed the temp on the R rear dually will run anywhere from 10 to 50 degrees warmer than all the others, although the tire doesn't feel particularly warm.  The tire pressures rise and fall appropriately and equally with speed, regardless of temp readings The exhaust is just in front of the R rear dually, just behind the galley door.  Has anyone had a similar issue where the temp sensor is reading the exhaust more than the tire temp?

I do have an IR temp gun coming to actually measure the tire separate from the sensor, so hopefully not an issue.  This may be a case where there is just plain too much information.  That then becoming perplexing and misleading just by the hot exhaust flowing over the dually with TPMS sensors--that is I hope.  Any thoughts appreciated.

Which (or both) of the RR tires shows this temp difference. Is it only when stationary or do you see this while driving. I don't monitor the temp on my RF TPMS sensors, but the PSI is about the same on all four rear tires on a 2019 Mercedes chassis.
Hopefully the IR temp reading will confirm that the difference is with the remote sensor.

Edit: I see you only mentioned not knowing the inner tire{s}. I installed aftermarket sensors (valve cap) on all 6 of my tires. Not sure what type TPMS you have.

Didn't get the IR out for the last short trip, so maybe today.  The concern is both outer/inside tires read similarly, again the pressures of both match the left side dually.  As it turns out getting a pressure reading on the back tires is a bit involved so the TPMS is useful for both, the inner was the one I was most concerned about, so I added the monitors to all 6 tires (and probably would to any towed equipment).  As it turns out the TPMS was fantastic when I developed stem leaks on on both my front tires after a tire change,  I knew of the leak prior to damaging the new tires.

The unassembled TPMS system that came with the RV is TST 507, has been worth the cost (if I needed to) despite potentially getting too much superfluous info, will update after IR readings.

If you have Borg long stem valves on the rear, most of your temp readings are from the air on the outside of the outer wheel.  Some does come from the stem.
If you don’t have Borgs, then it could the air temp between the duals.

Turns out I didn't need to use the IR meter (yet another item bought but not yet used) since I noticed the end of the tail pipe was no longer there--the exhaust was heading directly to the space between the tires.  The sensors are under the hub cap, wasn't able to find any extensions that would get the stems outside the hubcap.  I doubt the tires were heating up as much as the sensors since the temp would change quickly based on the engine running and the load on the engine.

Planning on a trip to the shop to see what a tail pipe will do to me.