Tire pressure variances question

[olustee bus]

I inflated tires to correct pressure before a trip and a week later, preparing for a return trip home I had lower readings and I think it was in the inner tire. The variance was on both sides of the rear. I have extensions.

This has happened often. Could it be that the extensions have that effect on the tp readings?

[Rocky Larson]

Only if they are leaking.
Ambient temperature can cause swings. Inside tires don't get the sun as much as the outer.
What are you using to measure. TPMS are rated for accuracy, are you within the +/- RANGE?
Take them off and give it a week. That should give you your answer.

[NYBobbo]

Originally Posted by olustee bus

I inflated tires to correct pressure before a trip and a week later, preparing for a return trip home I had lower readings and I think it was in the inner tire. The variance was on both sides of the rear. I have extensions.

This has happened often. Could it be that the extensions have that effect on the tp readings?

The extensions can effect the temperature reading but should not have any effect on the tire pressure.

Remember to fill your tires very early in the AM since as the sun comes up there will be a few pounds difference once the tires warm. You can tell the difference from the sunny side to shade side of your rig.

I have found some variation in how the tires warm when driving. Seems the inside tires get warmer than the outside, possibly due to breaking, or the fact that the inside rims are steel and the outside is Alcoa.

[hilgert]

Originally Posted by olustee bus

I inflated tires to correct pressure before a trip and a week later, preparing for a return trip home I had lower readings and I think it was in the inner tire. The variance was on both sides of the rear. I have extensions.

This has happened often. Could it be that the extensions have that effect on the tp readings?

Watching tire temperatures go up and down while driving is one of my hobbies. I've seen large differences between the sun side and the shade side on an open road, seen them all come down when driving at night, and all over the place when winding up/down mountains were the sun and shade sides change. I can also see higher temperature on tires closer to certain parts of the vehicle.

I always check my tires when the vehicle has been in the shade (on all sides) for some time. Having a TPMS makes it easy to check any time from inside the motorhome, and I've found our TPMS to be accurate within a pound or two (certainly within the accuracy of any gauge).

[THenne1713]

Soap bubbles and brush might work also, but LOOSE NUT on metal stem at the rim is what caused me to lose a tire after a few hundred miles; have read many negatives on stem extensions, but wonder if you cannot just get longer stems that work? Google/ Amazon here I come :-)

[NYBobbo]

yes, I had longer valves installed -expensive at around $220 but makes adjusting the pressure easy and can withstand having the TPMS valve caps on. Make sure you get the ones that fit your wheels - It took several attempts before the correct ones for my Alcoa wheels finally were installed.

extensions are prone to causing issues

[coachmanjay]

Replace all your extensions with DuallyValve solid stems. They will be the correct length and make checking and adjusting the pressure very easy and they don't leak. They are mounted on the wheel itself so require the tire to be dismounted. This can be done for $12 to $25 per tire depending on where you have it done. (could be no cost if you are a customer of the tire shop). Many tire shops sell them at a better cost then buying direct from Borg Equip.

[wa8yxm]

Extensiohs are known leak poihts. many of them leak a bit. (Many do not) they are not recommended because of that.

However another thign is sunlight. You inflate the tires COLD. ok then you go to someplace sunny and the sun heats the OUTER dual. Increasing the pressure.. you might be surprised at how much.