Tire pressure variance on duallies

[ACZL]

For those with duallies and TPMS, how much are your tires off from same side or axle? Example: if front axle requires 70 PSI, are both tires at 70 or is 1 and the other 65? How much difference do you allow?

[Sam_Spade]

ACZL wrote:

Am asking that if your dash readings say the tires for each axle are off by 4-5 lbs compared tom the other tire(s), is that okay.

Yes.
Especially if they are all ABOVE the recommended setting.
Those on-tire sensors were NOT intended to be watched like a hawk.

[Grit_dog]

^ Ok, my bad. I haven't run into those issues. Id go off the gauge pressure and call it done.
Fwiw I had a new trailer tire, never been done the road, lost half its air last week about a week after it was installed. Other 3 were good, new valve stems and flawless rims.
Ended up the tire was not seated all the way, it popped and creaked as I filled it back up.
Thinking about this thread, I been checking it every day or so to make sure it's not leaking down before the trip tomorrow. For kicks I used 3 or 4 differnet random pressure gauges. All the gauges were within 1-2 lbs.
you can't go wrong using the pressure gauge.

[ACZL]

Grit dog wrote:
Seems weird to have a bunch of bad sensors on a 3 year old truck, but stranger things have happened I spose. But the tpms has nothing to do with what pressures you run. Member used to be a day long long ago when a tire gauge WAS your tpms?
So was the question really about compensating for a leaking tire?
Fix the tire air up the tires to your desired pressure and drive away.
Next caller.

Am asking that if your dash readings say the tires for each axle are off by 4-5 lbs compared tom the other tire(s), is that okay.

Was told by AP that Ford did have issues w/their '17 sensors. Yes, I agree I shouldn't have any probs, but I do.

[Grit_dog]

Seems weird to have a bunch of bad sensors on a 3 year old truck, but stranger things have happened I spose. But the tpms has nothing to do with what pressures you run. Member used to be a day long long ago when a tire gauge WAS your tpms?
So was the question really about compensating for a leaking tire?
Fix the tire air up the tires to your desired pressure and drive away.
Next caller.

[ACZL]

I'm going off the TPMS on truck for each tires PSI. However, I check the PSI w/ a long gauge I bought from NAPA No Parts before we go on a trip to get to same PSI readings on all 6 tires (at least to what gauge says) and have only gone on 2 trips thus far. Anyways, the front axle, left tire may read 75 while right tire may read 70. Rear axle: left outside---well that sensor will be replaced once Ford gets them in stock but currently reads around 50. LR inside 65. RR inside 65, RR outside 61. Both rear outside sensors were replaced by independent shop, but will have Ford do 'em again. All checked cold, but once under way, the steers are somewhat equal, but still off by 3-5 lbs. Rear insides dead even. Right outside is within 3-5 lbs like the steers. Left outside--that's in a league by itself until I get it fixed again. In the meantime, I air it up 5 lbs more than inside for a w/e trip to allow for it to leak some.

Now I did buy and will carry a Viair 12v compressor just in case I need it while away from home.

So like one poster said, as long as all the tires are of equal PSI according to tire gauge even tho it may not be the same reading as the TPMS, good to go. That's what I've done the past 15 years.

Thanks for the replies folks

[Grit_dog]

If this is something that requires any real level or thought or consternation, one needs more hobbies or activities!
And define “same”. Now that I got a few vehicles with TPMS, it seems it is pretty close to gauge readings. And of the random gauges I have floating around, all appear to be pretty close. Newver gsve any thought to a couple psi difference.
Unless maybe drag racing or circle tracking.

And if being “accurate” or the “same” super important, do you take into account lateral weight bias per axle. Weight of fuel and passengers can make a big difference dontcha know!

[Durb]

You can calibrate a thermometer with boiling water. There are "certified" to be accurate tape measures. Torque wrenches are tested with higher accuracy test equipment which are calibrated with weights. I suppose you could send your tire a gauge to a Cal-Cert lab and have it tested but what is the point if it cannot be calibrated, pass or fail?

On my dually I use the gauge that is long enough to to reach the inner wheel and use it on all the wheels. It may not be accurate but at least they are all the same.

[Vette_Racer]

I set mine cold using a good quality pressure gauge, then just use the TPMS as a guide in case one gets really low, the TPMS never reads the same as the gauge and is usually off by several LBS tire to tire.

[Xflyhighx]

Snap on make one that works great. It put air in or out and it is digital and tenths. They are pricey but are accurate.

[wanderingbob]

Very few gauges will read the same ! Use the same gauge for all measurements and realize that a few points will not make much difference . Once at a pick up point for " jack rabbit pickup " we compared four gauges and all read different and each of us knew ours was correct,

[JTrac]

Look at the KTI 89001 Digital Tire Inflator on Amazon. I've had mine for a couple of years. It is easy to use and appears to be fairly accurate. It does match up with pretty well with the monitors in my Ford and the wife's Acadia.

[Sam_Spade]

Tvov wrote:
Why would you allow tires on duallys to have different pressures?

There may be a varying of pressures as you drive throughout the day, the tires are designed to handle this.

Seems like you answered your own question.
Once rolling, it is not something that you "allow".

[Sam_Spade]

ACZL wrote:
How much difference do you allow?

It is not something that you really have any control over.

You set them properly COLD and then don't worry (too much) about what they do as they heat up. I have seen differences approaching 10 PSI but that is just going by the TPMS and the accuracy on mine varies all over the place.

Trying to find out WHY would be long and expensive.....and generally pointless. The difference is mostly created by a slight difference in the wheel and maybe air flow. If one side is constantly in the sun, that makes the outside tire hotter too.

My take: Don't worry about it. The TPMS is there mostly to notify you of air loss.

[SweetLou]

Tvov wrote:

Each of my vehicles has its own tire pressure gauge in the glove compartment. When I get a new tire pressure gauge, I compare its' pressure readings with other gauges such as on a service stations air line. As long as it is close, I go with it. Tires are designed to function with a few pounds pressure differences.

So you accept the fact that you might want 60 psi but really are getting 55 or 65? It doesn't matter what a gas station's gauge says because you are comparing it to an unknown standard and I would think we can do better than that. Does anyone have a good idea about a good brand that really reads correctly?