TPMS Observation

[dan-nickie]

I noticed on my TPMS that my rear 'inside' duals seem to run 2-4 lbs PSI higher after they warm up after several miles.
I'm not sure why this is?
So a couple days ago I decided to set the cold pressure a couple lbs lower on the 'inside' rear duals.
Now when the all warm up, they have the about same amount of pressure across all 4.
I feel better this way.
YOur thoughts????

[dan-nickie]

OP here.
Well I really don't think a couple lb difference is any big deal either.
What got me thinking about it was that I had a blowout on an inside rear the day before.
Two year old Michelin Load class E. The Michelin dealer judged it a 'defective' tire and I got a new one for $35 pro-rated.
All tires were set that morning for proper pressure.

Like I said, I don't think the different pressures were/is a problem, it's just that blowouts get your mind to thinking about stuff and wanted to know what you guys thought about it. 🙂

[CA_Traveler]

RCMAN46 wrote:
I have found the sun is not much of a factor after about 20 miles. I have found the tires on the sun side of my trailer run at the same temperature as the shade side after about 20 miles of travel.

T ome the most important thing to watch for is a change in pressure after 20 miles and that all tires on the trailer are near the same. If I see a tire changing pressure when the others are not there is usually something going wrong on that tire.

Typically I see 20F+ difference in the SW.

[29FlyinDutchmen]

So FYI, 10 degrees of temperature change = 1 psi change

[RCMAN46]

I have found the sun is not much of a factor after about 20 miles. I have found the tires on the sun side of my trailer run at the same temperature as the shade side after about 20 miles of travel.

T ome the most important thing to watch for is a change in pressure after 20 miles and that all tires on the trailer are near the same. If I see a tire changing pressure when the others are not there is usually something going wrong on that tire.

[lanerd]

I set all tires on my coach and toad in the early morning hours. All the tires on the coach (8) are at 110 and the toads four tires are set at 35. Within a few miles of driving, my tire pressures all differ from each other by as much at 1 to 2 pounds on the toad tires and up to 5 or 6 pounds on the coach.

There are just too many pressure/temperature factors involved, so I just don't worry about it. Now if a tire differs on my tpms by more than 10 lbs, then i start to worry and will stop and check out the offending tire (hasn't happened yet).

Ron

[CA_Traveler]

Air flow is one reason a inside dual can be warmer. Many roads have a slight crown which can cause the inside dual to be warmer.

But the really BIG factor is the sun. The outside dual and front tire on the sunny side will be much warmer than the inside dual and the other side.

So should one adjust the tire pressure based on the suns location? :S

I run all tires on an axle at the same cold temperature setting.

[ron_dittmer]

TPMS data varies from sensor to sensor. This based on experience with my 2003 Corvette with TPMS. The sensors are there for general monitoring and notification of a significant drop in pressure. Not for pound-by-pound accuracy. When I want true equal tire pressure, I trust a good tire gauge.

I agree with bob_nestor.

[darsben]

What would happen if you moved the offending TPMS unit to a different tire?
could be that the unit is a bit different than the others.
couple of pounds difference is a difference to ignore

[bob_nestor]

Was the difference in tire pressure ever a problem before you had TPMS? Probably not, so why should it be a problem now?

Having too much information can be as disabling as not having enough information. I see this a lot with engineers at work. They become like deer caught in the headlights - surrounded by mountains of information that they can't sift thru to find the simple answers. Their "solution" is to gather even more information, hoping that the correct answer will just fall out on it's own.

I use the TPMS on my vehicles to report on tire pressure before I start driving and to notify me when there's a significant drop in pressure while driving. In between, I don't bother.

[Roadpilot]

They run hotter then the outside tires due to lack of airflow, which causes the pressure to go up. I've never worried about the difference, maybe I should,