How close should the pressure be on the tires on the same side of the trailer?

[Jeff in Ferndale Wa]

On a trailer with two or more axles, do the tires on the same side need to be exactly the same pressure when checking cold?
I drove mine a couple hundred miles where they were 61 and 65 when starting out(as measured by the TPMS). Recommended pressure is 65
Of course the pressure increases when the tires warmup,but there was still a 4-5 pound difference between them.The temps warmed up, but seemed to stay the same between the two tires.
I corrected it, but I wonder, will that small amount of difference cause excess wear on either of the tires?
Probably would not have given it a thought if not for the TPMS that I never had on any other RV I've owned.

 

[NSRV]

Even 1 psi can make a difference. The lower the air pressure the more the tire is squished down, which means more surface road contact on the tire with less air pressure, so in theory it could technically cause one tire to wear faster than the other. On a trailer its probably not as important as it would be on a car or truck, but I would generally try to keep the tires within 1-2 psi of each other when cold. Also different tire pressures can also cause the wheel speeds to fluctuate or differentiate from each other, which isn't good for anything.

EDIT: Also under inflation and over inflation can also cause the tire to wear unevenly, which also isn't good.

 

[Isaac-1]

It is not all that important as your trailer axles have an equalizer linkage between them, where it is much more important is with dual rear wheels.

 

[Kirk]

I use a digital tire gage and air mine to within 1#.

 

[SpencerPJ]

I wouldn't worry about it. Glad you corrected it.

 

[edjunior]

4 - 5 pounds is probably a bit excessive, but within a pound or 2 I would think is probably fine. I like to keep mine all exactly the same, but in practice, it is a little tough to do.

 

[Henry J Fate]

The effects of tire pressure differential on dual+ vehicles can be detected by the tire temperature. Low tire pressure results in higher heat.

Also... Inside tires on duallyz will vary in temp and pressure some due to the solar exposure which is shielded by the outside tire.

All this stuff is rather picky but it's good practice and healthy to follow and understand tire pressure changes and the results.

 

[Seon]

I venture to say most folks use a cheap pressure gauge, so unless one invest in a high dollar pressure gauge, then a couple of pounds won't make a difference.

 

[Gary RV_Wizard]

As a practical matter, 1-2 psi is "close enough". Even if they are set to the identical pressure when cold, you will likely see a couple psi difference as they heat up while driving.