Tire inflation phenomenon - need input

[Joatmon]

This sounds crazy but I cannot get my trailer tires to inflate more than 60psi. This is a new fishing boat and the recommended pressure is 90psi.

Both tires are acting the same. The compressor pressure switch shuts off at 105psi. I verified the pressure at the end of the hose with a gauge to be 105. I have tried two different chucks. I replaced the valve in the stem. The tire inflated rapidly to 50psi then slowly increases to 60psi then stops filling. Weirdest thing I have seen. I cannot understand why the tires will not fill beyond 60pis. Are there pressure safety features on new tires stems? New valve did not make a difference. I get full flow through the stem when the valve is removed.

What am I missing?

 

[Bruce]

What make and model are the tires.

90psi sounds more like maximum pressure when hot not a cold fill pressure.

On the compressor, if not in use does it reach 105? Many compressors will not take a tire that high. 50 to 60 psi is typical for trailer tires. 35 PSI would be typical for a car tire.

 

[ralphsmithiii]

Wow, 90 psi? I suppose I'm new to trailers but my 2019 Shorelandr trailer for my 2015 AR240 has 14" tires with a max PSI rating (they are I believe long haul rated?) of 50psi cold.

 

[Joatmon]

What make and model are the tires.

90psi sounds more like maximum pressure when hot not a cold fill pressure.

On the compressor, if not in use does it reach 105? Many compressors will not take a tire that high. 50 to 60 psi is typical for trailer tires. 35 PSI would be typical for a car tire.

I agree with what you are saying. 90 seems high especially for 2 ply tires. The tires are Load Star 4.80 x 12. What confuses me is the inability to equalize the pressure between the air source and the tire. 105psi supply should fill a 60psi vessel without issue. Boyle's Law.

The compressor is rather large so 105psi is not an issue. My skinny bicycle tires require 90psi and they fill to pressure without issue.

 

[Need A Vacation]

@Joatmon,

Unless I’m reading the tire wrong from what I can see, you have C rated tires which have a MAX OF 50psi!!!

The 90psi I believe is for seating the bead of the tire during installation....

Double check the wording on the sidewall!!!

As for your compressor not airing the tires higher, what compressor model??? It could be it just doesn’t have the guts to air a tire higher.

 

[Need A Vacation]

@Joatmon,

Unless I’m reading the tire wrong from what I can see, you have C rated tires which have a MAX OF 50psi!!!

The 90psi I believe is for seating the bead of the tire during installation....

Double check the wording on the sidewall!!!

As for your compressor not airing the tires higher, what compressor model??? It could be it just doesn’t have the guts to air a tire higher.

So I just did a search and that tire is listed as 90psi in their website.... As a load range C??? Last I knew all C rated tires were a max of 50psi.... So I’m baffled!!!

Can you take a pic showing more of the sidewall?

 

[Joatmon]

Load rating is the load on the tire and based on the construction, rotation speed and pressure. You cannot say all C rated tires are at 50 psi max.

Sidewall shows 90psi for that particular tire at the load C rating. No bead seat pressure is noted. Compressor model or type should not matter. 105psi is 105psi no matter how it is compressed or the time it takes to get there.

A 105psi air supply should equalized when connected to another vessel such as a tire.

Thanks for you suggestions.

 

[Andy NJ]

90psi is correct for that size and load rating. Is your gauge accurate? Respectfully asking.

 

[Seadeals]

Also respectfully trying to help...does your compressor cycle back on (running) when you are trying to fill the tire?

 

[Joatmon]

Sorry for being blunt. Please don't take me wrong. I know everyone is trying to help. Being an engineer I am not always tactful with my response. Just ask my wife. Engineer personalities are a whole other topic. I do appreciate the input.

The compressor has a large tank so once it reaches 105 is does not start back until pressure is down to 95. Having a large tank it does not cycle much.

I did verify the gauge is made to read up to 150psi. Being an electronic gauge that could be the issue. I will get another gauge to double check the pressure the current gauge is accurate.

Thanks

 

[Need A Vacation]

I don’t recall seeing a C rated for anything other than 50lbs. But after posting did see it’s a bias ply... maybe that’s part of it. I swear my sled trailer 12” tires are an E at 80lbs...

As for the compressor & tire gauge, not sure what to suggest.. Only asked because if it was a small compressor maybe it just doesn’t have the guts. Did read-read and see it’s a larger one though...

Do you have a vehicle with the tpms? Maybe compare the gauge and the factory system???

 

[Joatmon]

Good idea but both cars are Audi and they monitor tire fill by rotation distance and not by actual pressure so no internal sensors reading a pressure for comparison. Different I know.

I’m going to get an analog gauge to verify pressure. Cheap Chinese Slime gauge may be my issue. It that is the case I was lucky the tire did not pop off the rim. Happened to me many moons ago and I still see the scar.

 

[Dixie Highway]

Usually you have to buy a truck specific gauge to read above 60 psi, I’d make sure to get a good analog gauge.

 

[Joatmon]

Problem solved. As recommend I checked the gauge again. It is not a 150psi gauge but a 60psi max gauge. I bought an analog 100psi gauge that holds the pressure reading. I had 86psi in the tires.

The other problem was my lack of patience. When the source pressure and receiving pressure are close it takes a long time to equalize the two. I was not waiting long enough to fill the tires. Albeit I was already at 86 it took a few minutes to get to 90.

Thanks for all your help.

 

[bronze_10]

Man that seems high!

 

[Joatmon]

I know but it is a small tire. 4.8 x12 and the markings show 90psi. The tires on my other fishing boat I sold were 60psi. Of course these are made in Vietnam so they have to be good. Yikes!

 

[Jgorm]

90 is crazy. You probably need to wait for the compressor to catch up. A compressed rated at only 105psi is probably very small.

 

[Joatmon]

Not too small. 25 gallon tank with 1 hp motor.

 

[Bruce]

Not too small. 25 gallon tank with 1 hp motor.

1 hp is quite small for a 25 gallon tank. I would expect 3 to 5 hp.

 

[Joatmon]

The plates does not have hp but it shows 15 amp @ 110vac which is 1 hp. Along with 75 feet of hose there is enough tank volume that the compressor lets me top off my car tires before kicking in. The hysteresis of the pressure switch is 105-95.