Tire Pressure Differences On Same Axles

[tropical36]

Originally Posted by CWSWine

I see a lot of talk about cold pressures but very little about the difference between tires on the same axles.

On the front tires, what are your limits of difference in pressure left and right?

On the back dual tires, what are your limits of the difference of pressure between the dual tires on the same side?

Rear dual tires on the same axle?

I've never weighed each wheel individually. Only the axles and then add 10 - 15psi over the chart specs. for this possible variable, among others that one will encounter in their travels.

[travelinJ]

Personally I defer to the manufacturer when it comes to operation of their products. The manufacturer designed, produced, and hopefully tested the product and knows the limits.

In this case the original question can be answered quite plainly as has been earlier mentioned by a manufacturers user guide. The Michelin truck tire guide as seen here.

Set tire pressure on a cold tire, do not bleed tire pressure of a hot tire and no more than 5 psi difference of any tire on a axle. Since the guide says no bleeding of hot tires, the 5 psi difference is on cold tires.

As had been drilled into me over the years, use a high quality, accurate tire pressure gauge that has been verified or calibrated in the recent past.
In my opinion TPMS are not a good substitute for obtaining an accurate tire pressure. Too many variables in a TPMS system to rely on for an accurate reading. I believe TPMS are designed for gross changes in air pressure not repeatable fine tuning.

[Morguns1cam]

I bought a tire pressure monitor system last year, Ive always known that as the tire heats up the pressure goes up but never realized how much! I start out cold with 95 psi, once the tires heat up, especially on a hot day theyre up to 120-125psi, was wondering what do you normally set the high pressure alarm to?
Cam

[Morguns1cam]

"As had been drilled into me over the years, use a high quality, accurate tire pressure gauge that has been verified or calibrated in the recent past"


where do you get a tire pressure gauge calibrated?

[CWSWine]

I know our local commercial tire dealer can check your gauge for accuracy and give +- PSI. The one I own there is no way to adjust it.

Originally Posted by Morguns1cam

"As had been drilled into me over the years, use a high quality, accurate tire pressure gauge that has been verified or calibrated in the recent past"


where do you get a tire pressure gauge calibrated?

[garyre]

Yes, you can have them set up for TPMS and continuous monitor both inside and outside tires separate. The crossfires equalize the pressure in both inside and outside tires and also have an emergency detection in the event one tire loses pressure that prevents the other from deflating. I am very pleased with them and also run TPMS.

[travelinJ]

As mentioned above a reputable tire shop will have a known source to verify their gauges. Preferably a shop that installs truck tires as their known source will typically be set at 100 psi.
Inexpensive (cheap) gauges are not adjustable. If they become inaccurate, typically replace them with another cheap gauge.
Personally I have at least three gauges on hand at any point, most of which were free giveaways from various vendors. A quick way to verify basic accuracy is to use a known stable source such as a relatively large pressure vessel (air tank or large tire) and compare gauges. Three checks of each to avoid operator induced variations.
If all three gauges read within a pound or so of each other I consider the gauge verified. If one is way out of wack, I'll check it again. If still way off, I'll replace it. At two pounds difference I consider it suspect, at 4-5 psi difference I consider it garbage.
Professional adjustable gauges typically are very expensive and in my opinion not worth the effort unless you have a known source, check it frequently AND know how to adjust it correctly.

[TTD]

There's no better feeling than when I look down at my TPMS and all the tire pressures are reading EXACTLY the same (along each axle).

Sadly, after a little while - one will usually go up or down a pound and the feeling is gone.

[Crasher]

Originally Posted by Morguns1cam

I bought a tire pressure monitor system last year, Ive always known that as the tire heats up the pressure goes up but never realized how much! I start out cold with 95 psi, once the tires heat up, especially on a hot day theyre up to 120-125psi, was wondering what do you normally set the high pressure alarm to?
Cam

If the cold psi you start at is at or above the minimum psi to carry the load, then any increase in pressure from rolling resistance and OAT is normal and designed into the tire. Keep in mind that if the OAT is 20-30* warmer than when you started, your 95 psi would be over 100 psi just from the increase in air temperature without moving the coach. So on a hot day it would be normal for an 18-20% increase, which is what you have when you factor in the OAT increase. With your pressures, I would set the high pressure alarm @ 130 psi. I set all of mine 5-10 psi above normal running pressures after the tires have reached their highest normal running psi.

[Gary RVRoamer]

In my opinion TPMS are not a good substitute for obtaining an accurate tire pressure. Too many variables in a TPMS system to rely on for an accurate reading. I believe TPMS are designed for gross changes in air pressure not repeatable fine tuning.

I don't see any reason to believe the wheel sensor in a TPMS is any less accurate than any other digital gauge pressure sensor. And what other variables are there? Besides, even professional grade mechanical or digital gauges are rated about plus/minus 1% or sometimes even 2-3%, which can put you off 1-3 psi on a 100 psi tire. That's plenty close for setting pressure.

[beenthere]

as always Gary your common sense answers are always appreciated. seems some just can not believe if they didn't read. its not always black and white, there are always variable's and common sense solutions

[twinboat]

Originally Posted by Morguns1cam

I bought a tire pressure monitor system last year, Ive always known that as the tire heats up the pressure goes up but never realized how much! I start out cold with 95 psi, once the tires heat up, especially on a hot day theyre up to 120-125psi, was wondering what do you normally set the high pressure alarm to?
Cam

That is why adjusting you tire pressure a few PSI, thinking it will change the ride it handling, is a futal exercise.