Tire pressure monitor?

[jasin1]

Originally Posted by jadatis

Also keep in mind, that TMPS also introduces new things to worry about. Then if you learn, what is important, and what not, you yudge the readings better.

1. Temperature reading of external sensors isworthless, because it gives the temperature of the end of the valve, and not the gascompound in the tire ( fi air or Nitrogen).
And even internal sensors dont always give temp of inside tire gascompound, metal valves transport the temp of rimm and outside tire air to the sensor.

But you can calculate the pressure back from the pressure, rising.

For that I made a list.
Gives pressure filled at 70 degrF, and the temperature rising ( or lowering) per psi.
So look up the pressure you fill cold at 70 degrF back in this list, and remember or write down the degrF/psi behind it.

Then on the road if you see 5 psi pressure rising on tmps , multiply by the degrF/ psi, and add that to 70 degrF, and you know more exact the temperature of the inside tire .

Never 100% exact, but better then what sensor gives. And because of all the inacuracies also never exact. So you can do rough calculation by head while driving, acurate enaugh for the purpose.

Pressure measured at 70 degrF/ degrF per psi.

70degrF./degrF/psi

20 psi/ 15,5F/psi
21 psi/ 15F/psi
22 psi/ 14,5F/psi
23 psi/ 14 F/psi
24 psi/ 13,5F/psi
25 psi/ 13,5F/psi
26 psi/ 13 F/psi
27 psi/ 12,5 F/psi
28 psi/ 12,5 F/psi
29 psi/ 12 F/psi
30 psi/ 12 F/psi
31 psi/ 11,5 F/psi
32 psi/ 11,5 F/psi
33 psi/ 11 F/psi
34 psi/ 11 F/psi
35 psi/ 10,5 F/psi
36 psi/ 10,5 F/psi
37 psi/ 10 F/psi
39 psi/ 10 F/ps
40 psi/ 9,5 F/psi
42 psi/ 9,5 F/psi
43 psi/ 9 F/psi
45 psi/ 9 F/psi
46 psi/ 8,5 F/psi
49 psi/ 8,5 F/psi
50 psi/ 8 F/psi
53 psi/ 8 F/psi
54 psi/ 7,5 F/psi
58 psi/ 7,5 F/psi
59 psi/ 7 F/psi
63 psi/ 7 F/psi
64 psi/ 6,5 F/psi
70 psi/ 6,5 F/psi
71 psi/ 6 F/psi
77 psi/ 6 F/psi
78 psi/ 5,5 F/psi
86 psi/ 5,5 F/psi
87 psi/ 5 F/psi
96 psi/ 5 F/psi
97 psi/ 4,5 F/psi
109 psi/ 4,5 F/psi
110 psi/ 4 F/psi
126 psi/ 4 F/psi
127 psi/ 3,5 F/psi
148 psi/ 3,5 F/psi
149 psi/ 3 F/psi
177 psi/ 3 F/ps

Huh??……that’s a lot of numbers
.
.refrigeration uses a pressure temp relationship because a particular gas has a specific pressure at a specific temperature…you can figure out what kind of refrigerant is in a system based on that( as long as it isn’t multiple types thrown in.

But I believe the tpms on the valve stems use an internal temp sensor that measures the inside wheel air temp itself….I have multiple different hvac instruments that do that ..or it converts it in its reading displayed

This is from my faq questions for my tpms monitor..it states the temp is from within the tire not external

[wegone]

Originally Posted by Mikelff

I double check my tire pressure every morning that I tow with a high end accurate tire gauge, and adjust if needed. The flow through sensors are great and takes just seconds to confirm cold tire pressure. I have steel stems because I’m running G rated tires. Max 110 Psi. You are correct though, the flow through require metal stems.

Mercy...110, that is a keg.

Why do they say max pressure anyway, shouldn't a tire be designed to a optimal pressure fill?
Not sure why they offer a range, or do they?
Seems your load might better be adjusted according to the suspension???

[Courser Farm]

Again, TST 507. Have been using them for 15 years.... replaced the monitor with the newest one last year. Purchase extra sensors and keep a couple with us in the camper. Have saved us at least 2 blowouts. AND the folks at the TST number answer the phone day and night. I know because when I first got them, I called a few times for help and they are fab. Have called over the years- somebody always answers. I'm in charge of them because as I've said before, the Boss doesn't like to read directions. LOL

[flybouy]

Wow, this all seems complicared, convoluted, overthought, and down right rediculouse. Jeeze, maybe it's just me but I don’t see the difference between taking the cap off an flow thru sensor and taking off a "standard sensor", at least not at the 80 psi my tires require. And what's all this pressure adjustment tables stuff? Are you going down a NASCAR track with your rig? Check the tire pressure with a tire pressure guage? I bought a TPMS so I wouldn’t have to do that. If I don’t trust it I'd throw it away. Am I missing something here?

[jasin1]

Originally Posted by flybouy

Wow, this all seems complicared, convoluted, overthought, and down right rediculouse. Jeeze, maybe it's just me but I don’t see the difference between taking the cap off an flow thru sensor and taking off a "standard sensor", at least not at the 80 psi my tires require. And what's all this pressure adjustment tables stuff? Are you going down a NASCAR track with your rig? Check the tire pressure with a tire pressure guage? I bought a TPMS so I wouldn’t have to do that. If I don’t trust it I'd throw it away. Am I missing something here?

What? You don’t have one of these on your dash?? I thought we all had one..got mine originally from CW…

[flybouy]

Originally Posted by jasin1

What? You don’t have one of these on your dash?? I thought we all had one..got mine originally from CW

I'm old school. Took Calulous using a slide rule. I'll be damned if I'm pulling over to calculate my tire pressures.

[wiredgeorge]

All this gobbledy-goop got me thinking. Was out a month ago and my Guta TPMS worked fine. Wasn't sure about two things:

1. If I air up my tires anticipating a new trip, do I need to re-pair with my dashboard control box. To pair initially, I just held the sensor next to the box before install.
GUTA TECH SUPPORT SAID: NO - It will take a few miles for the new pressure to display.

2. All four of my PSI readings showed up within a few miles going out to the campground but one took about 20 miles to show up on the way in. Why?
GUTA TECH SUPPORT SAID: Did you have your cell phone near the inside monitor? If so, the cell phone radiation may interfere. (I did).

I learned a couple things and wanted to pass this along.

Last bit of advice... Like all things discussed on a RV forum, the self appointed gurus will over complicate things and while they may offer sage words of wisdom, if they make no sense and you survived without that wisdom previously... well just move on.

[FlyingAroundRV]

Originally Posted by travelin texans

Whatever system you chose I'd recommend a couple things;
#1 it gives pressure & temperature readings
#2 batteries are user changeable
#3 my opinion is that it must have its own monitor that displays temps/pressures constantly, not using your cell phone.
#4 be sure to have metal valve stems installed on all the wheels.

I'll second all that except the metal valve stems. They are good IF you can fit them to your rims. My rims won't take them but I've been running with standard stems for two seasons and over 20,000 miles with no problems … yet
PS, I have the TST 507 with flow thru sensors.

[Tireman9]

I have been running TPMS since 2009. Since 2011 I have been doing a direct comparison of two different systems on my Class-C w/6 tires. (The only direct comparison I know of)
I am running the TireTraker 500 external system vs the TST internal system. S0 for both have worked well at 26°F to 102°FR ambient temperature.


As a tire engineer I can tell you to not get too hung up on the temperature readings and the Pressure readings from my 12 sensors are accurate to +/- 2.3%. I write a blog on RV Tire Safety and have been publishing performance reports.


I can recommend either system.

[travelin texans]

I've found the the TST507 temps are very near the tire temps compared to .y infared temp gun, close enough for me anyway & I don't need a scientific calculator to convert either of those temps.
I originally ordered the flow thru sensors but found it made to stems too long for the inside wheels on a dually, TST swapped them at no charge. I also removed the security devices off all the sensors, too big a PITA especially with duals. I figured if someone walking by & knew what they were that if they needed that bad they could have them.

[jasin1]

Originally Posted by jasin1

What? You don’t have one of these on your dash?? I thought we all had one..got mine originally from CW

Edit: joking of course. I just have the tpms. It’s all I need

[Tireman9]

Originally Posted by Island Eddie

Mercy...110, that is a keg.

Why do they say max pressure anyway, shouldn't a tire be designed to a optimal pressure fill?
Not sure why they offer a range, or do they?
Seems your load might better be adjusted according to the suspension???

Federal Reg require the tire be capable of supporting 50% of GAWR and RVIA regs require a tire be capable of supporting 55% of GAWR.


Using the Max load capacity of a tire is the lowest cost way for RV Company to meet those requirements. Only a very small number of companies put larger tires (more load capacity) tires on the RV because that cuts their profit margin.

[Tireman9]

Originally Posted by jasin1

Huh??……that’s a lot of numbers
.
.refrigeration uses a pressure temp relationship because a particular gas has a specific pressure at a specific temperature…you can figure out what kind of refrigerant is in a system based on that( as long as it isn’t multiple types thrown in.

But I believe the tpms on the valve stems use an internal temp sensor that measures the inside wheel air temp itself….I have multiple different hvac instruments that do that ..or it converts it in its reading displayed

This is from my faq questions for my tpms monitor..it states the temp is from within the tire not external

Not sure if I agree that an external TPMS is reporting the temp of the air inside the tire.

1. Air is a good insulator so why / how would that small column of air inside the stem override the temperature of the Brass stem that is conducting heat directly from the rim to the metal base of the sensor?

2. My test of running both an internal and external sensor shows the external sensors run 20F to 30F cooler than the internal sensors
3 Tire pressure with change by about 2% for each change in temperature of 10°F. I posted the mathematical proof on my blog.

[sourdough]

Originally Posted by flybouy

Wow, this all seems complicared, convoluted, overthought, and down right rediculouse. Jeeze, maybe it's just me but I don’t see the difference between taking the cap off an flow thru sensor and taking off a "standard sensor", at least not at the 80 psi my tires require. And what's all this pressure adjustment tables stuff? Are you going down a NASCAR track with your rig? Check the tire pressure with a tire pressure guage? I bought a TPMS so I wouldn’t have to do that. If I don’t trust it I'd throw it away. Am I missing something here?

No, No....Now Marshall I think we're missing something here. Maybe this tire pressure thing IS way more complicated than we've been thinking....or giving thought to!! I forgot....it's not yesterday....it's TODAY!! We NEED some air pressure tables, some daily calculations maybe even some graphs (Brent I've got that Python thing on order ). It CAN'T be easy.....right?

I gathered up some stuff off my desk to have DW throw in the console of the truck so I can do hourly calculations on the tires, temps etc. when traveling. Maybe make some homemade spreadsheets until I can get that gee whiz thing Brent linked to. I started a list of how I need to do this to "stay on top" of it but need to get some equipment to measure outside ambient temp vs the internal temp of the tire through the wall since the sensors don't tell us anything. I'm working on that but all I keep coming up with is a flat tire. Talked to DW about what we needed to compile and analyze and she advised we may never get out of one space by the time we did all that and made the calculations/graphs and IF we did we certainly wouldn't make it beyond the 1 hour stop to remeasure/graph everything. I'm working on that but looks like trips may be much longer in duration and much shorter in length....but I'll have a heck of a lot of numbers and paper!! (Note the slide rule in the pic )

[wegone]

As odd as this might sound, it's true.

I use to have a knob on my TV, and I turned it, to 1 of 5 stations....honest.
And I knew something was wrong on my first bike with its tire when it was rolling on the rim, instead of nice a smooth motion...every time the cause was because it was flat, I didn't have any instruments that needed to tell me that.

How I got through that primitive life, not sure how....well, I guess I was just chosen.

[flybouy]

Originally Posted by sourdough

Welcome to the forum. I and many others use the TST 507 system and highly recommend it.

Originally Posted by jasin1

Edit: joking of course. I just have the tpms. It’s all I need

I wasn't. No way an I pulling over to chipher on my fingers and toes (broke that slide rule years ago playing fetch with a dog).

[Gunny Mike]

We use the Tire Minder for our 2nd year now. We bought the 4 stem unit for the TT only. The alligator clips for the booster could be better as one already rusted out. I didn't put the anti theft device on as its easy to take them off and test the device for a rapid release. I use them for an accurate psi reading when I keep the tires at 80 PSI. I also went out a bought a VIAR digital air gun for my compressor to fill up the tires. It locks onto the stem better. The HF air gun and gauge were great for a few fill ups but the locking latch was not locking onto the stem after a while. Will probably change out the batteries next year.

[flybouy]

Originally Posted by sourdough

No, No....Now Marshall I think we're missing something here. Maybe this tire pressure thing IS way more complicated than we've been thinking....or giving thought to!! I forgot....it's not yesterday....it's TODAY!! We NEED some air pressure tables, some daily calculations maybe even some graphs (Brent I've got that Python thing on order ). It CAN'T be easy.....right?

I gathered up some stuff off my desk to have DW throw in the console of the truck so I can do hourly calculations on the tires, temps etc. when traveling. Maybe make some homemade spreadsheets until I can get that gee whiz thing Brent linked to. I started a list of how I need to do this to "stay on top" of it but need to get some equipment to measure outside ambient temp vs the internal temp of the tire through the wall since the sensors don't tell us anything. I'm working on that but all I keep coming up with is a flat tire. Talked to DW about what we needed to compile and analyze and she advised we may never get out of one space by the time we did all that and made the calculations/graphs and IF we did we certainly wouldn't make it beyond the 1 hour stop to remeasure/graph everything. I'm working on that but looks like trips may be much longer in duration and much shorter in length....but I'll have a heck of a lot of numbers and paper!! (Note the slide rule in the pic )

Feel like I should have a time & tide table, moon phase calendar and Capurnicus on speed dial. When I learned how to fly I used a paper disc " flight computer" that wasn't that detailed. Got to admit when the DW bought me a Jeppesen Sanderson one gor Christmas it was nice. Still kept the manual one as a b/u as it didn’t rely on batteries.

[P&DZ]

Mikelff
You mentioned you use a high end accurate tire gauge. Can you please provide the details on that gauge. I have two dial tire gauges and neither read the same or correspond to the GMC TPMS.

[Javi]

I got a TS something or 'other 507 something and I turn it on to see if my tires are somewhere between 105 psi and 115 psi... yep... I'm good

Heck.. it's 96 degrees and one side says 102 and the shady side says it's 94.. but the spare says it's 89 degrees and107 psi...

Now what the heck do I do...��