“What is recommended to monitor RV tire pressure? I check my dual tires with a hammer when on the road. I also use a gauge from time to time, but I’m looking for something a little better.”
As you may know, I monitor a number of RV Forums. I recently saw the above question. So here is my answer:
I am currently running the ONLY (as far as I know) direct comparison of Tire Pressure Monitoring Systems (TPMS): a TireTraker™ external vs. TST® internal.
Every “review” I see on the internet is basically someone’s opinion based on the use of one system, but I do not see anyone presenting actual data showing the accuracy of either the Pressure readings or Temperature readings. Sometimes I have noticed the “review” has links to sell the units that someone has “recommended,” but I do not see any direct comparison data or test results. I’m wondering if those posting the “review” are just interested in selling products?
I started my direct comparison of TPMS brands/types in March 2018 and have test data on Pressure and Temperature readings from 26°F to 98°F in actual service, along with a direct comparison of all 12 sensors for pressure accuracy measured on a custom-built test fixture.
While internal TPMS normally report hotter temperatures because the sensor is not being cooled from external air, I can report that the temperature difference runs about 20°F cooler on external sensors. Except for that difference, I would consider BOTH systems essentially identical when it comes to reporting pressure, which is more important than temperature readings.
The original poster on the Forum said he was looking for something better than the “Hammer Test”. Here are my observations on that test.
Tire pressure “Hammer Test”
While working as a Tire Design engineer (about 45 years) I was able to observe the “Hammer Test” when a dozen experienced (more than 500,000 miles driven) truck drivers were all presented with the opportunity to “Check” the pressure on two truck tires. As I recall, one tire was properly inflated to 105 psi and the other was set to 50 psi. We ran the test twice over the day and switched the tires around. Half the drivers could not consistently or correctly identify the tire with low pressure. Three of the remaining six did identify the low tire in both tests, but provided estimates from 30 to 75 psi. Only three truck drivers were able to correctly and consistently identify the 50 psi tire as being between 45 and 55 psi both times.
If you remember that any tire operated with a 20% or more significant loss of air is considered “flat,” the test results do not support the value of a Hammer Test other than the fact that if a tire has lost 75% or more of its air the “hammer” might tell you something was wrong.
What TPMS do I recommend?
With some 30,000-plus miles of use, I feel comfortable recommending either system, as the small variation in PSI reading and temperature readings are not, in my expert opinion, meaningful to the average user. I have replaced a number of batteries in the external system and expect the internals to need new batteries soon.
What is important, even if you get or already have a different system, is to be sure you test your system at least once a year, as I covered in this post.
It is also important that you program the warning levels for your RV, as the factory setting of the TPMS may or may not provide sufficient advanced warnings for you. Here is what I do.
Bottom line. I can recommend either system. I do suggest that any TPMS be purchased from someone that supports the RV community and that has a phone number and web page with info on the TPMS. There are some low-price units. But, personally, I think a TPMS with Lifetime Warranty is a good deal.