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TPMS Question

austinjenna
Explorer
Explorer
I recently installed a TPMS system and was wondering what the high limit is folks used as compared to what their PSI is. So my trailer tires are at 80 PSI and noticed they went up to 89 PSI on the way home. How much of a rise is there normally in tires so I know what to be able to set the high PSI alarm on?

Thanks

2010 F350 CC Lariat 4x4 Short Bed
2011 Crusader 298BDS 5th Wheel
Reese 16K
12 REPLIES 12

CA_Traveler
Explorer III
Explorer III
rlw999 wrote:
CA Traveler wrote:
Check your tire specs for the maximum pressure. TST indicates it should be about a 25% increase.


The maximum pressure on the sidewall is the maximum *cold* pressure, so it doesn't really help determine the max pressure for warm tires.
OK The TST 507 manual states the pressure data charts plus about 25%. Hence the psi is based on the actual weight the tire is carrying after it is weighed plus 25% for the TPMS.
2009 Holiday Rambler 42' Scepter with ISL 400 Cummins
750 Watts Solar Morningstar MPPT 60 Controller
2014 Grand Cherokee Overland

Bob

austinjenna
Explorer
Explorer
Thanks for the replies. I think I will set the high at 96 and take it from there. For the low I will set at 70

2010 F350 CC Lariat 4x4 Short Bed
2011 Crusader 298BDS 5th Wheel
Reese 16K

rlw999
Explorer
Explorer
CA Traveler wrote:
Check your tire specs for the maximum pressure. TST indicates it should be about a 25% increase.


The maximum pressure on the sidewall is the maximum *cold* pressure, so it doesn't really help determine the max pressure for warm tires.

Beverley_Ken
Explorer
Explorer
As the others have said, TST recommends 10% below and 20% above. One hot summer, I got the over pressure alarm 104psi , high for the 80psi tire pressure was set for 96 but all tires were equally high, I reset the high for 105 psi.
Another note, one trip I used my infrared temp gun and found tire temps just over 150F. I checked the 18 wheeler beside me in the rest area and his temps were 175F/

Ken
2006 Winnebago Outlook 29B E-450.
2012 Honda CR-V AWD
Blue Ox Aventa LX tow bar and Brake Buddy Vantage.

Bobbo
Explorer II
Explorer II
I use 10% below to 20% above. For an 80psi tire, I would use 72psi as lower limit and 96psi for upper limit.
Bobbo and Lin
2017 F-150 XLT 4x4 SuperCab w/Max Tow Package 3.5l EcoBoost V6
2017 Airstream Flying Cloud 23FB

FWC
Explorer
Explorer
For reference, a 20% increase in pressure would be a ~60C (~100F) increase in temperature over ambient - that is getting really hot. If you saw that on your TPMS, you would want to pull over and check things out.

bob213
Explorer
Explorer
What "ford truck guy" said x2
You can avoid reality, but you cannot avoid the consequences of avoiding reality – Ayn Rand

CA_Traveler
Explorer III
Explorer III
Check your tire specs for the maximum pressure. TST indicates it should be about a 25% increase. I've seen 10% which does not include hot summer days on the MH.

I have both an internal sensors system (Smart Tire) and TST. The psi difference is 1 psi. The internal sensor temperatures range from 41 to 54 derees higher than the TST values. I attribute this to the TST sensors being mounted outside the tire on brass valve stems and rotating itn ambient air. In other words external sensors have significant lower temperatures than the actual tire temperature.

Stopping and quickly measuring the tire sidewall tempeatures resulted in values 6 to 26 degrees below the internal temperature.
2009 Holiday Rambler 42' Scepter with ISL 400 Cummins
750 Watts Solar Morningstar MPPT 60 Controller
2014 Grand Cherokee Overland

Bob

Lwiddis
Explorer II
Explorer II
Nine pound increase in an 80 psi tire is normal.
Winnebago 2101DS TT & 2022 Chevy Silverado 1500 LTZ Z71, WindyNation 300 watt solar-Lossigy 200 AH Lithium battery. Prefer boondocking, USFS, COE, BLM, NPS, TVA, state camps. Bicyclist. 14 yr. Army -11B40 then 11A - (MOS 1542 & 1560) IOBC & IOAC grad

I just installed the TST 507 series and they set it up for me... I run my tires at 115 psi... the low is set to 103 psi ( 10%) and the high is set to 144 ( 25% ) ..

They told me the standard was 10% for the low and 20-25% for the high setting

I just ran from PA to Richmond VA which was around 300 miles... 1st half was rain and mid 60's.. the psi was 120-122 psi... the 2nd half was sunny and mid 70's... the psi was 138-140... I am curious to see what they show when running in 100 degree heat down south......
Me-Her-the kids
2020 Ford F350 SD 6.7
2020 Redwood 3991RD Garnet

FWC
Explorer
Explorer
The rise in pressure is due to an increase in temperature. Much more than a 10% increase in pressure could indicate you have a problem with a sticking brake or wheel bearing, so setting the high alarm at 10 - 15% over the cool pressure would probably be wise.

fj12ryder
Explorer III
Explorer III
The rise will depend on the ambient temperature to a certain degree (HAR).

Personally I don't worry too much about high pressure, but probably 10-15% rise would be common. I would be more concerned with low pressure, and high temperatures. Those are better indicators of potential problems.
Howard and Peggy

"Don't Panic"