Questions for TPMS users

oldtymer · 03-03-2018, 01:56 PM

I have a 2017 Thor Outlaw 29H and I have been researching TPMS for this coach. I have a couple of questions for TPMS users.

1. Has anyone used a TPMS sensor only on the outside tire of your dually set and, if so, can you reasonable tell from the pressure and temperature if the inside tire is loosing pressure? The theory being when the inside tire pressure goes down, the pressure and temperature of the outside tire will go up.

2. For those with tire pressure sensors on their Toads, have you changed out the rubber tire stem to rigid? If not, have you had any issues with the rubber stem fatiguing or breaking? I tow a pickup and a trailer, at different times, and both have rubber stems on their tires. I am wondering if I need to have all the tire stems upgraded to rigid or what I have will work.

Thanks for the information

gmc · 03-04-2018, 02:11 AM

Quote:

Originally Posted by oldtymer

I have a 2017 Thor Outlaw 29H and I have been researching TPMS for this coach. I have a couple of questions for TPMS users.

1. Has anyone used a TPMS sensor only on the outside tire of your dually set and, if so, can you reasonable tell from the pressure and temperature if the inside tire is loosing pressure? The theory being when the inside tire pressure goes down, the pressure and temperature of the outside tire will go up.

I would recommend sensors for each dually tire (assuming something like 'crossfire' isn't installed)... First I find my inner tires run hotter, and second you aren't just looking for low pressure - high pressure/temp warnings can prevent a blowout...
For the price of two extra sensors might as well have complete coverage.

Quote:

2. For those with tire pressure sensors on their Toads, have you changed out the rubber tire stem to rigid? If not, have you had any issues with the rubber stem fatiguing or breaking? I tow a pickup and a trailer, at different times, and both have rubber stems on their tires. I am wondering if I need to have all the tire stems upgraded to rigid or what I have will work.

I haven't changed stems on toad and no issues.

Oneilkeys · 03-04-2018, 02:25 AM

Absolutely the inside duallys should have sensors. The sensors on your outside tires will give you no information on what is happening to the inside tires. They could have a slow leak leading to a flat and you would never know. Relying on a rise in temperature of the outside tire to indicate problems with the inside tire seems like a bad idea.

bigben · 03-04-2018, 02:25 AM

Not sure about the theory of how you check temps/pressure inner and outer duals without a sensor. We have sensors on all six wheels and keep track of the status continually. Wouldn't be without it. Don't have sensors on our toad, so I cannot speak to those.

Dippytwo · 03-04-2018, 11:59 AM

I agree with the others about the sensors on the inside tires, you do need them. We also use them for our toad and have not needed to change the stems. But I do think you need the senors on the toad, because if one of my tires were to go flat I probably wouldn't even notice it.

Joe-FL · 03-04-2018, 01:09 PM

IMHO if you are gong to have TPMS on all your RV tires except your inside dual tires, then you might as well not have the system at all. The inside duals are the only tires that can go flat that you would not be able to notice while driving.

As far as sensors on your toad, I pull a enclosed trailer with my toads inside so I have them on all 4 of those trailer tires. They are rubber valve stems but with the TST TPMS you can use regular cap sensors with either rubber or metal screw threw valve stems. If you want flow through sensors then TST wants you to have metal valve stems. Not sure about other brands of TPMS since I have only owned TST brand.

RV Pirate · 03-04-2018, 02:28 PM

I'm always amazed at how the tire pressures and temps jump around during a trip. Definitely need sensors on all tires IMO.

oldtymer · 03-05-2018, 10:20 AM

Thanks to everyone who responded to my questions. The consensus seems to be to have a monitor on all tires including the inside tire on dually sets and that rubber tire stems are ok for the cap type sensors but not the flow through type sensors.

bjones3211 · 05-06-2019, 08:35 PM

Have a question I had my TPMS now for maybe six months and I’ve been trying to fine-tune it and have it set right now for my tire front tire supposed be 75 pounds I have the high set for 90 that’s 20% above and the rear tires supposed to be 80 so I have it set for 96 being that I live in the south it gets pretty hot here so the tires will actually go above the 90 and 96 so my question is is how high is considered safe to have it set on the high end also sometimes I get a high temperature setting what should I set it to you
Thank you

**16ACE27** · 05-06-2019, 09:27 PM

Quote:

Originally Posted by bjones3211

Have a question I had my TPMS now for maybe six months and I’ve been trying to fine-tune it and have it set right now for my tire front tire supposed be 75 pounds I have the high set for 90 that’s 20% above and the rear tires supposed to be 80 so I have it set for 96 being that I live in the south it gets pretty hot here so the tires will actually go above the 90 and 96 so my question is is how high is considered safe to have it set on the high end also sometimes I get a high temperature setting what should I set it to you
Thank you

On my ACE I run 82 PSI and have the high pressure alarm set to 100. It is not unusual for the inner rears to hit that on a hot day on the interstate.

Oneilkeys · 05-06-2019, 09:29 PM

Quote:

Originally Posted by bjones3211

Have a question I had my TPMS now for maybe six months and I’ve been trying to fine-tune it and have it set right now for my tire front tire supposed be 75 pounds I have the high set for 90 that’s 20% above and the rear tires supposed to be 80 so I have it set for 96 being that I live in the south it gets pretty hot here so the tires will actually go above the 90 and 96 so my question is is how high is considered safe to have it set on the high end also sometimes I get a high temperature setting what should I set it to you
Thank you

It’s complicated. The short answer is that tires are designed to handle the increased temperature and pressure of both the rise in temperature during the day and the increase caused by the friction of the road. If you set the tire pressure in the morning before you run the tires, then they should be ok. I routinely see tire temps of over 100 degrees on a hot Florida day running at 70mph. For all the info you will ever want go to the link below and look thru the tire track site.

https://www.tirerack.com/tires/tiret....jsp?techid=73

Beau388 · 05-06-2019, 10:20 PM

Starting with 86 psi @ 75 degrees in the rear duels with 6,000 lbs on the duals, I see 105-108 psi after an hour at 100 degrees ambient plus about an extra couple of psi on the sunny side. I usually cruise at 60 mph. The front singles start at 80 psi @ 75 psi and usually end up at 94-96 psi @ 100 degrees ambient. I start out with the dolly at 50 psi @ 75 degrees and it climbs to 61 psi on a 100 degree day. That data is based on empirical observations over the three years in South Texas. Remember it the flexing of the tire that produces the heat. The more flex the hotter the tire gets. Faster speed, more weight and lower air pressure increases the heat in a tire. The increase in air pressure is primarily a result on the heat in the tire.

Pete'sMH · 05-06-2019, 11:35 PM

I have found that a 20% spread between cold and hot alert is not enough. I run all 6 tires between 85 and 90 lbs and frequently get temp alarms. Especially on the rears. Unfortunately on my system you can’t adjust the high trigger independently. So I have my baseline set at 93lbs. No downside as the actual pressure is what displays. Easy solution

You may also like: