Tire Pressure - Caps, etc

Duner733 · 05-12-2021, 04:06 PM

I am all over the place on this one. My tire and RV are rates for 65psi.
I have two air compressors that claim I only have about 51psi.
I have a battery operated tire gauges that agrees with this.
The tire pressure caps are rated for 65psi and are green as in ok.
I have a manual tire gauge that agrees with the low 50lbs psi.

Does anyone know if there is a range on these caps before they show low?
I am guessing I need to add some air as the majority of my gauges claim it is low.

Any other suggestions as I am heading out early tomorrow?

Dan

TitanMike · 05-12-2021, 04:12 PM

Quote:

Originally Posted by Duner733

I am all over the place on this one. My tire and RV are rates for 65psi.
I have two air compressors that claim I only have about 51psi.
I have a battery operated tire gauges that agrees with this.
The tire pressure caps are rated for 65psi and are green as in ok.
I have a manual tire gauge that agrees with the low 50lbs psi.

Does anyone know if there is a range on these caps before they show low?
I am guessing I need to add some air as the majority of my gauges claim it is low.

Any other suggestions as I am heading out early tomorrow?

Dan

Those tire pressure indicating caps are notoriously inaccurate. If all your regular tire pressure gauges and compressor gauges agree with each other the message should be clear, the pressure indicating caps are wrong.

Inflate to the desired pressure using one of the 'good' gauges when tires haven't been driven on for several hours and forget the indicator caps.
They'll do a good job of keeping the dirt out of the stem but that's about it.

Duner733 · 05-12-2021, 04:16 PM

I think that is going to be my game plan. I have to fill-up in the am anyway.
I may not push it all the way to 65 but who knows.
We bought this in October of last year and been on 3 trips. We have never addressed tire pressure. I am guessing with storage over the winter, some air can be lost and this makes complete sense.

GeoKat · 05-12-2021, 04:28 PM

Ok so as a RV newbie (almost 4 months in full-timing) I have to make an idiot out of myself and ask. Those caps change color? I’ve noticed that they’re green but never thought twice about it. Go easy on a newbie. No one ever explained that aspect to me.

Duner733 · 05-12-2021, 05:09 PM

I'm here with ya buddy. Exact same scenario here, which is why I am concerned. Many of my tire gauges don't agree with the caps.

Hopefully the gas station I am going to has another legit gauge and give them a final answer.

So how many pounds off is too many? If I am supposed to be at 65psi, I am pretty sure 51psi needs to be addressed. But if I am running at 60psi, would that be adequate?

D W · 05-12-2021, 05:29 PM

A number of factors come into play here:

1. Do your tires say "Inflate to 65 psi"?, or

2. Do they say "Max inflation single XXXX lbs 65 psi"?

3. What is the weight of your "loaded" rig?

NOTE: Inflation psi is always cold, not a heated tire.

**Flybob** · 05-12-2021, 05:42 PM

You said: " Those caps change color? I’ve noticed that they’re green but never thought twice about it. " Are they really pressure indicating caps or are they just made out of green plastic that is used to indicate that they are/maybe were filled with Nitrogen.

charles l · 05-12-2021, 05:52 PM

At least air them to what the manufacturer label says. If that is 65 psi air them to 65 psi. You need the weight of the loaded rv first. Then look at the load inflation chart for your tires. Air up to the psi listed for your load when the tires are cold. I would also recommend getting a tpms so you can monitor your pressure and receive warnings/alerts.

rickkey2 · 05-13-2021, 05:01 PM

Ok if you think that the valve caps change color with pressure then take one off and see what happens. My caps are green as to designate nitrogen filled. Tire says inflate to 65 pounds which is max. Trailer tires should be filled to max pressure that is stated on the tire. I would say that your guages are correct. Inflate to 65 lbs. TPMS is highly recommend as to keep track of tire pressure and temperature.

RadRik · 05-14-2021, 08:48 AM

Quote:

Originally Posted by Flybob

You said: " Those caps change color? I’ve noticed that they’re green but never thought twice about it. " Are they really pressure indicating caps or are they just made out of green plastic that is used to indicate that they are/maybe were filled with Nitrogen.

X2 My thoughts exactly.

mikeyk101 · 05-14-2021, 10:41 AM

I'm wondering if two different style caps are getting confused in this thread. The top ones are supposed to indicate whether tires are at the correct pressure but I have never had success with them. The bottom ones are just regular plastic caps that are used instead of black caps when tires are filled with nitrogen instead of regular air.

mfMcFroggierPod · 08-07-2021, 02:34 AM

Let some air out of the tire and see when the indicator changes. But I would a least air up to the trailer data tag label psi. It will not hurt to inflate to tire cold max psi; it might just give you a rougher ride for the trailer. Good Luck.
But 15psi low is awaiting a tire related problem.

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