Trouble airing up to 80 lbs rear.

Boudreaux · 02-06-2018, 03:52 PM

When I first purchased the Greyhawk, I realized the rear tires needed 80 lbs. I used my small "tried and true air compressor", but quickly discovered It would run too long and get hot.

We were on the road in Roswell, NM (July '16) so I stopped in at Sears spotted this unit and purchased it. The compressor seems to have good specs for airing up.

Sears.com

Today I checked the tires because of an upcoming gathering this weekend. The tires had not been checked since Nov because the couch is in the building unused.

The tires were right out 6 to 9 lbs low.The compressor is set at 115 lbs. It seemed to work very well in the beginning. I only used the unit three times to air up in the past. Yet, I had a hard time airing the rear tires back up to 80 lbs. Bring those tires back to 80lbs seemed to take "forever". any ideas ...

WinnieView · 02-06-2018, 04:01 PM

Get a bigger compressor?

Stop by a local tire store and ask for help?

Les7h · 02-06-2018, 06:33 PM

I have the same compressor & love it but it is not a substitute for a real compressor - it will get you by at the Campground or on the side of the road but it is limited in it's capabilities
Les

Crossingover · 02-06-2018, 07:22 PM

We use the Viair 12V compressor to air up to 110 psi with no complaints. A great unit.

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MD3 · 02-06-2018, 07:27 PM

I have an older variant of that compressor. Mine works okay to about 100psi... 110psi I need is a struggle for my coach.
What I had to do is get the compressor running (bleed some air off the compressor if needed) and before it shuts off start inflating the tire. This way the compressor is filling the tire and you are not filling the tire off the air tank.
Not sure why it works better this way but it seems to work on mine and I’m filling to 110psi.

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MrJackSprat · 02-07-2018, 07:51 AM

I would think that compressor should be sufficient. You may want to check the valve stem (or extender) & make sure you are getting a snug fit or no obstructions.

GrumpyDad · 02-07-2018, 08:45 AM

Sounds like everyone has you on the right track, but here's some thoughts.

1) your compressor has to be rated a fair bit higher than the final tire pressure you are aiming for. If you have a big home air compressor with an adjustable regulator, try setting it to 80 PSI and see how long it takes to fill those tires. Ages! Set that same compressor at 120 PSI and they'll fill just fine in much shorter time.

2) That pressure drop from the compressor pump, through the tank (if your compressor has one) through the hose, fittings, valve stem etc, is what's actually doing the work to allow the air to flow. I've messed around with my setup many times and from what I can figure from all the gauges, I have a drop of almost 15 PSI while the air is flowing!

Overall, the kind of compressor someone might carry on the road for emergency use is no substitute for a "real" air compressor that they keep at home. I like the 5-gallon "pancake" style, which is reasonably portable, but still has enough jam to do things like filling big tires to 80 PSI and for winterizing the plumbing in my trailer.

Wertles · 02-07-2018, 09:15 AM

That compressor should be just fine to give the tires a 10 PSI bump. It’s not the biggest thing out there but it has enough PSI and reserve tank to top tires off. I think something in the system is off. Either the unit is not producing 135 psi, your regulator is set too low or your chuck is leaking or not delivering air like it should.

1. Make sure the unit produces the 135 PSI. If it doesn’t, take it back if possible.
2. Turn the regulator (if it has one) all the way up. You need good pressure to drive air into the tire.
3. Replace the piece of crap chuck that Sears included with a higher quality one. I can’t tell you how many $3 chucks I have seen fail.
4. Only fill the tires when the compressor motor has stopped. You will have enough pressure to drive air into the tire and won’t be relying on the pump to try and fill the tank and tire at once. Yes, it will cycle quite a few times with only a 3 gallon reserve tank but it makes no sense to carry around a 30 gallon tank.
5. All else fails, use somebody else’s.

33 RLDS · 02-07-2018, 09:18 AM

Viair makes some nice 12V air compressors. Most others are just cheap noise makers that struggle with a football

mohok1 · 02-07-2018, 10:07 AM

On the lighter side, if you have 80 PSI in the "rear", I hope I'm not near by!!!

jd99336 · 02-07-2018, 12:44 PM

I have a cheapo compressor similar to that, and 80 psi is no issue at all. I even rebuilt the compressor when the diaphram blew out a few years back so it is old and well used. As Wertles noted, something else is afoot here as 80 psi should be a problem on that volume of tank. I did buy a good quality US made combo gauge and chuck (NAPA I think....wasn't cheap but really nice and accurate). Other than that, check all of the issues noted. Your tank pressure gauge should wind up to the rated psi and then it is just a matter of ensuring your regulator is cranked up to the max it will go. Don't put your regulator at 80 psi or it will take forever. Put it at 120 or more and it will fill more quickly.

xmtraveler · 02-07-2018, 12:59 PM

I agree with all, you need a more powerful compressor. A few years back when I was towing a 5th wheel with my F-250 diesel I purchased a compressor I saw on Ebay for I think somewhere between $60-75 that will go up to 150psi and can pump up to 30 or 40 minutes without getting hot. It is necessary to connect the compressor directly to a battery as it draws down on 30A. It is very similar to the one Camping World is selling today for nearly $300. I suppose someone from the factory in China acquired a few and decided to sell for such a low price. At the time I saw others advertised for nearly $200. I needed 80psi in the truck tires and the small compressors just could not infllate them. Bottom line I think you just need a bigger and more powerful compressor not the 12V cigarette lighter plug ins.

TCNashville · 02-07-2018, 01:07 PM

I just bought this one. https://www.ebay.com/itm/Viair-300P-...0AAOSwjUhaRL9u

xmtraveler · 02-07-2018, 04:12 PM

Looks very similar to the one I purchased a few years back. You may have to increase length of line cord to battery to inflate rear tires. This should work for you because it inflates fairly quickly.

GrumpyDad · 02-07-2018, 06:14 PM

Real danger of a blowout in a situation like that. Could tear your family apart....

repacs0103 · 02-07-2018, 06:22 PM

I use a ryobi one+ portable compressor. 150 psi, no cords or hoses, works with all my 18v batteries and chargers, 25 bucks at homerville.

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michael.g · 02-08-2018, 07:40 AM

Quote:

Originally Posted by Boudreaux

The tires were right out 6 to 9 lbs low.The compressor is set at 115 lbs. It seemed to work very well in the beginning. I only used the unit three times to air up in the past. Yet, I had a hard time airing the rear tires back up to 80 lbs. Bring those tires back to 80lbs seemed to take "forever". any ideas ...

That compressor should have no problem filling tires to 80lbs, even with the regulator set at 115 lbs. My guess is the problem is not the compress, but the valve stems or extenders.

With our Greyhawk, after a couple years, the inside rear tire on the street side got almost impossible to fill. I ended up removing the valve extender and putting it back on to make sure it was on tight. After that, I did not have a problem airing up the inside rear tire.

When we replaced the tires, I had the mechanic install Tireman
Dually Valve Stem Kits. They are longer valve stems, not extenders and work much better than the extenders that can come loose and make difficult to air tires.

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