Tire pressure monitoring system
- Thread starter jnutt
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dave10a
Well-known member
The best tire monitor for temperature and pressure are ones that are mounted inside the tire. Valve stem types do not give an accurate representation of tire temperature. Inside tire monitors signals are mitigated with all steel belted tires because the signal is attenuated more that non-steel belted tires.
LBR
Well-known member
TST for us....shows pressure and tire temperatures good enough for DW to notice a problem as we're towing...set your custom high and low alarms for what you wish.
I pull out my IR gun every stop (every couple of hours) and shoot the tire treads and center of wheels for a hub building heat, then make mental notes of any issues.
I pull out my IR gun every stop (every couple of hours) and shoot the tire treads and center of wheels for a hub building heat, then make mental notes of any issues.
jerryjay11
Well-known member
Also TST. Besides tire pressure and temperature you can set it to give an under-pressure or over-pressure alarm.
dave10a
Well-known member
hmm, the TST is a good product for tire pressure, but I don't see how it can accurately provide tire temperature. Can someone provide comparison data of tire temp using an IR temp sensor as compared to the TST reading. I suspect the TST is reading outside ambient temperature more so than tire temperature. If the tire temp reading on the TST is approx. 50 deg higher than outside ambient temperature after traveling at highway speed for an hour then that may provide comfort the reading is representative of actual tire temp.
I believe the main advantage of TST is that it will work well with steel belted tires, where as the inside tire monitors are better at temperature. If some one can claim other wise, please provide empirical evidence.
I believe the main advantage of TST is that it will work well with steel belted tires, where as the inside tire monitors are better at temperature. If some one can claim other wise, please provide empirical evidence.
danemayer
Well-known member
Measuring the temp outside may not be as accurate, but it's sufficient. If the temp on one wheel climbs dramatically, you have a problem. But if you're using a TPMS to manage tire temperature to a specific temperature reading, IMO you're overthinking it.
dave10a
Well-known member
Did not mean to start an argument, I was simply providing an technical point about the difference between TPMS monitors for folks to consider. For example Ford offers in tire monitors with a obscure warning that they are not to be used with steel belted tires which is important to know before you purchase it. Also Heartland has offered in tire (Valor) monitors in the past without informing folks that they should not be used with steel belted trailer tires. Temperature is important to monitor and outside monitors are simply not as RESPONCIVE as in-tire monitors. I question why one would rely on tire temperature with outside monitors while traveling not to be argumentative, but as a learning point based on empirical data.
I forgot to mention that passenger cars and truck do not have the problem with steel belted tires because of very close proximity of the transmitter/receiver, but the proximity of trailer transmitter/ receiver is significantly greater and may require of repeater to reliably pick up a highly attenuated signal from a transmitter behind steel belted tires.
LBR
Well-known member
Been a while since our last good road trip, but for me when the TST shows a said tire at 85-90°, it's outside tread will shoot between 120-130°. When traveling steady hours N and S on I-5, the sun side 3 tires will show on our TST 5-8° warmer than the off-sun side 3 tires.
It will not show exact tread temperatures....it is for comparisons between tires.
It will not show exact tread temperatures....it is for comparisons between tires.
jerryjay11
Well-known member
If the valve mounted sensors are reading just outside air temperature I would need to understand why if the outdoor temp is 70 degs and the TST monitor while driving tells me my tires are at 80 degrees to 84 degrees and pressure running 10 to 12 psi higher how the increased temperature is not reading the air in the tire which is circulating within the tire. Outdoor air temperature didn't increase. But next time I tow the TT I will use my laser temp gun to compare.
dave10a
Well-known member
You have the right idea
BTY It is measuring a combination of outside and tire temp which is weighted to mostly outside temp, but it is not a true measurement of tire temp. However, it is normal for inside tire temp to reach approx. 50 degrees above ambient while traveling 60mph which is a good indication if the tire temp is being monitored accurately. Of course the sunny side temp will be higher as well as load on the tire because many trailers have different loading on each tire.
jerryjay11
Well-known member
Don't know where you are getting your data from because even on the hottest day towing TT through Colorado and Arizona my truck tires (with internal sensors) never increased by 50 degrees using my infrared temp gun. Maybe 15 to 20 degrees with a correlating tire pressure of around 10 - 12 psi. I guess it would depend on load, tire design, speed, road temps, etc. and would be different for each traveler.
158 degrees is considered safe for all tires per TST and tires fail between 170 - 200 degrees. Even if they are not 3 -4 % accurate, if I saw my tires getting up to 100 degrees I would pull over to investigate, though my tire pressure is only 50 psi.
Also according to TST the temp sensors are accurate to 3-4% temp and pressure. I have an inquiry in for TST Technologies for further explanation and next time I take the TT for a ride I will check with infrared and sensor to compare, then return to provide an update.
158 degrees is considered safe for all tires per TST and tires fail between 170 - 200 degrees. Even if they are not 3 -4 % accurate, if I saw my tires getting up to 100 degrees I would pull over to investigate, though my tire pressure is only 50 psi.
Also according to TST the temp sensors are accurate to 3-4% temp and pressure. I have an inquiry in for TST Technologies for further explanation and next time I take the TT for a ride I will check with infrared and sensor to compare, then return to provide an update.
dave10a
Well-known member
My data comes from my Valor in-tire sensor that is measuring accurately and rapidly temperature inside of the tire on my rig with 7000lb axles. Also Valor claims that 50 degree increase is normal for my rig. Also Trailer Life magazine also had an article a while back sustantiating that in-tire sensors are more accurate and more rapid response than outside sensors. I would like to also add that I saved my axle after a bearing failure on I80 in Nevada because I seen the tire temp go from 125 degree to 140 degrees on one wheel. The tire monitor did not alarm because its alarm is set for 170 deg, but I knew something was wrong and stopped before sever damage occurred. The rear left hub was too hot to touch, but were not smoking. I really doubt an outside tire monitor would have shown that temperature increase soon enough to prevent damage that would have resulted in a smoking bearing and possible loss of a wheel. I always monitor temperature over pressure at all times, because if pressure was going down I would get an alert, but temperature does not alert (170deg) until things are really bad mechanically. The tire can handle up to 170+deg but that is not the whole story...
jerryjay11
Well-known member
Interesting thoughts and this is a good conversation for anyone pulling a trailer long distances. I also read that article and from that article this is what I am attempting to get across. Maybe not as exquisite as Mr. Pittman. Here is part of that article that reference what I was saying:
http://www.trailerlife.com/tech/qa/rv-tech-qa-tire-temperature-monitoring/
Valve stems, metal or rubber, are not insulated, so that’s going to affect the temperature reading by a small amount at the tip. However, the air inside the tire is constantly circulating during travel, and even that small amount of air in the valve stem will be changing as you drive, so it’s going to be fairly close.
In general, the temperature readouts are most valuable for relative comparison to the other tires. All of the tires will be reading out their temps under identical mechanical setups. Being aware if one tire’s temperature starts to increase due to low pressure, for example, relative to the other tires, is the important detail.
Article by Larry Pittman | Fenton, Michigan
http://www.trailerlife.com/tech/qa/rv-tech-qa-tire-temperature-monitoring/
Valve stems, metal or rubber, are not insulated, so that’s going to affect the temperature reading by a small amount at the tip. However, the air inside the tire is constantly circulating during travel, and even that small amount of air in the valve stem will be changing as you drive, so it’s going to be fairly close.
In general, the temperature readouts are most valuable for relative comparison to the other tires. All of the tires will be reading out their temps under identical mechanical setups. Being aware if one tire’s temperature starts to increase due to low pressure, for example, relative to the other tires, is the important detail.
Article by Larry Pittman | Fenton, Michigan
So ladies and gents, I have a new cyclone 4270 and I had a valve stem tpms system in it that allows me to set a floor and ceiling on both pressure and temp, what would you recommend for those settings before the alarm sounds?
Thanks,
Tom
dave10a
Well-known member
The "constantly circulating" part is theory and needs to be proven by the author. The best proof would be to compare both types of monitors at the same time in the same conditions. That circulating air sounds good but I could argue that it is speculation and does not take into accounts eddy currents, temperature gradients and air velocity vs time of travel. The "relative comparison" part of the article is the best advise, but the response time for temperature gradient change is in question. In other words will you detect the change before bearing damage occurs? I speculate the in tire monitor would be more responsive because it deals directly with the air inside the tire rather in the valve stem that is subject to gradient differential, eddy currents, velocity and outside ambient temperature. Also the response time of the thermocouple and associated electronics in any senor comes into question. Evidently my Valor was responsive enough for me to catch a bearing failure before it became a real problem, albeit I have to keep random(alert) observation while traveling. The thresholds are not adjustable and are set at the factory, but they do sell a tool the will set the thresholds.
LBR
Well-known member
It actually let's you set an alarm for a LOW temperature reading?
