Community Forums

frederick w · 03-19-2013, 01:12 PM

I have a Sears electric air compressor that I find hard to operate. It's rated up to 125.

Difficult to put more than 70 psi in my tire (19.5 rim). Tires are to hold about 80 psi. It's kind of hit and miss. Iv'e checked the press. with 3 different air guages.

Don't know what I'm doing wrong. If I had the big bucks
I would just buy a new diesel MH with an on borad compressor

Buford B · 03-19-2013, 02:16 PM

Not sure what model compressor you have but I'd guess you have a built in adjustable regulator that is set at 70 psi. Find the knob and turn it clockwise.

JohnBoyToo · 03-19-2013, 06:17 PM

our 150 psi craftsman (so far) has done great --- I tried 2 different 12v compressors and a harbor freight 100 psi compressor and neither would push their max pressure at all....

others here have raved about the 150 psi model and so I jumped at it for $83 @ kmart online !!!

Fred and Bonnie · 03-19-2013, 06:34 PM

JohnBoyToo has a good point, 12v units don't cut it. I have a Husky, 120v, rated at 125 and have no problem getting to 105psi.

fred

Ed S · 03-19-2013, 06:45 PM

You may want to try to take some weight off the tire you want to fill by lowering you jacks.

Gary - K7GLD · 03-19-2013, 07:05 PM

Quote:

Originally Posted by JohnBoyToo

our 150 psi craftsman (so far) has done great --- I tried 2 different 12v compressors and a harbor freight 100 psi compressor and neither would push their max pressure at all....

others here have raved about the 150 psi model and so I jumped at it for $83 @ kmart online !!!

YUP - absolutely NO complaints with ours - 100 PSI, 19.5 wheels...

Lindsay Richards · 03-19-2013, 07:22 PM

We have the Sears 125# unit with a 4 gallon tank. It has 2 regulators on it so you can also use it to run air operated tools like nailers. I just adjust the one regulator when using the nailer (around 60#) and then max it our when filling our tires to 95#'s Works great. It isn't the fastest thing around. It takes a couple of minutes go from 80 to 95 #. I used to have a Chinese made Wl-Mart 125# unit and returned it. Junk. The bigger the tank, the quicker things go. The 4 gallon tank is the biggest unit that would fit into my coach bay.

H. Miller · 03-20-2013, 04:47 AM

80 PSI is 80 PSI, ETC, etc. If one has weight on the tire (or not) has no bearing on pump pressure.........

DGBPokes · 03-20-2013, 07:54 AM

I have a medium sized 110 v. compressor in the garage. I like to carry 100 psi in my motorhome tires. At first I had trouble, In that all I could get out of the compressor was 95 psi. I learned that it has a safety feature, and I have to "trick it" to get it to go higher. If I really crank down on the regulator to about 120 psi, then I open the relief valve and let the tank go down to about 85 psi, the compressor will kick on and run it up to the 120 psi. It will not turn the compressor on again until the tank goes down to 85 psi. Which means air is equalizing in the tank and the tires.I am sure it is some kind of OSHA safety feature that is designed in. The other thing, is these tires are so big, with so much pressure, it takes several minutes to get air in. If you think about how quick you fill a bicycle vs. a car, then extend that to RV tires.

HOWEVER..... I do NOT leave it at that pressure except when airing my tires. And when it runs up, I make sure I am not standing next to it. You can even see the air line expand extra at 125. Just saying, be careful, these things can be dangerous.

TRAILERKING · 03-20-2013, 08:02 AM

Quote:

Originally Posted by Ed S

You may want to try to take some weight off the tire you want to fill by lowering you jacks.

Sorry but pressure is pressure and weight on the tire has no bearing...

frederick w · 03-21-2013, 05:55 PM

Thanks guys for the imput.

Part of my problem was faulty air guage (Kobalt dial one from Lowels). They were very reluctant to to replace it, but they did. The new one worked, but don't buy one (bad reviews).
Another part of the problem is by valve stem inner wheel extensions.
Will post a new thread on that one as I think alot of people ran into this problem.

Gary RVRoamer · 03-25-2013, 07:23 AM

People quote the compressor psi rating but that is only half the spec. You also need to be concerned about the air volume (cfm - cubic feet per minute) - rating. Inexpensive compressors often provide a high psi but very low cfm at higher pressures, so it won't actually push enough air into a tire to be useful. It is very simple to design the compressor mechanics to produce very high pressures, e..125, 150 or even 200 psi, but the amount of air actually delivered goes down in proportion to the increase in pressure. It takes a more sophisticated design and more expensive components to deliver a higher cfm volume at high pressures, so cheaper units often fall short.

Look for a compressor that is rated for at least one (1) cfm at 80 psi. If your tires require 100+ psi for full load, you want a compressor that can do 1+ cfm at that pressure as well. The psi rating only needs to be about 25 psi greater than the max pressure you will use.
If the compressor doesn't show the cfm rating at various pressures, I wouldn't buy it, since that almost surely means the value is inadequate. If it was good, they would be advertising it in big print!

"007" · 03-25-2013, 07:36 AM

I have a Sears 125 compressor that plugs into 110 outlet. 10 years old and still working used to inflate 235x80 22.5 tires 95 lb & 85lb.
When I use it put pressure gauge up to 125 and load tires checking with double sided truck gauge, has worked for me no problems.

JBDISCOVERY · 03-25-2013, 07:55 AM

I have a Sears 125psi AC compressor which works great. Good value. Use it to inflate the rv tires plus air nozzle dirt cleanup plus spray painting.

To get max pressure, I agree with the post saying that you have to "trick" the compressor to attain max pressure by pulling the pressure release valve. Then the unit will push air into the tire at 100+ psi. Trick it again to finish the tire.
JimB