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Poor Man's Four Wheel Drive

It has always been a mystery to me how travelers inflate tires. Your chances of finding a functional and non-vandalized air pressure pump at a gas station are a bit better than finding a functional pay phone. But even so, it's hard to get near the air pump with your trailer. The alternative is to carry one of those cheesy 12 volt tire inflators; years ago they were slow and would burn up. Are they better today?

Of course most people don't deliberately let half the air out of the rear tires of their tow vehicle, and then put it back in.
Half-inflated tires on the drive axle comprise a poor man's four-wheel-drive. I had my RV in Baja once and saw a Mexican hot-rodding around the beach on soft sand with his rear-wheel-drive car. The tires were noticeably deflated. It was amazing what he was capable of doing. Ever since then I have used the same trick to pull my trailer through loose or steep roads. Of course that means raising the pressure when you get back on pavement. (Low pressure and high speeds would result in tire heating and shortened life.)

It worked half-well to use a portable 1000 Watt generator to run a (Black and Decker) 110 VAC tire inflator, despite it making the Devil's own noise and having a cheesy valve fitting. When it burned up a couple years ago I vowed never to buy another one.

Despite my diatribe against the False Prophets of Downsizing and Minimalism (grin), the fact is that I'm obsessed with getting these crappy inflators out of my life. There's only one 110 VAC tire inflator on the market (Campbell-Hausfeld, $55.) But I can't think of an alternative. How does everyone else do it?


I use a bicycle floor pump for my trailer tires. They are never down more than 3-4 pounds. The Truck tires do not seem to leak down between oil changes when they are checked.
I agree with what you said but it doesn't help me put the air back into the rear tires of my tow vehicle, after I've let half of it out to help me through loose stuff or get up steep roads.
Anonymous said…
I know you want to get away from the 12V pumps, but I'm going to suggest one anyway. I use one that came with a "Slime" kit. I've had it for several years and it's held up very well. You are probably familiar with Slime, which I once used in inner tubes for my fat tire bike when I was riding in Sand Bur country. I don't use it any more having discovered the advantages of Kevlar belted bike tires. Anyhow, if you can find it, the 12V pump that comes with a slime kit is pretty substantial.

Tom in Orlando
Tom, you didn't say whether that 12 Volt DC pump with the Slime brand could pump up full sized pickup truck or van tires in, say, 10 minutes.

Indeed, I saw that pump at Walmart and it looks quite substantial. But aren't cigarette light connectors limited to about 5 Amps DC, or 60 watts? That doesn't sound very powerful.

The trouble with all this tire inflator biz is that it's aimed at rescuing damsels in distress in roadside emergencies, which occur every three years; if the pump works once and burns up, the customer is probably happy. My application is at the other end of the spectrum.
Anonymous said…
Boonie, As you suggest, I've never pumped up a full sized tire, only topped off my vehicle tires when they need it, 5lbs or so, At the end of adding air to four tires, the pump is hot and I always do wonder if it's going to burn out. So far it hasn't and I'm happy with it for my application, but for yours as you describe it, probably not. I recently purchased a small travel trailer and without thinking, assumed that I could use the pump on my trailer tires... but in reality, due to the cord length, I have to position my tow car beside the trailer, and then the other side to get the trailer tires aired up. So, I too am looking for a better solution.

Tom in Orlando
Ted said…
No idea if it suits your needs/desires, but I've had good luck with the $99 110VAC Sears compressor w/1.5 gal. air tank. About 140 psi max and it fits with room to spare where a hypothetical passenger would put his or her feet.

It'll raise the pressure of the tires on my 21' motor home from 60 psi to 71 psi in about ten seconds. Noisy as heck since I need to run my generator plus the compressor, but I don't need to top off my tires very often. A necessary evil, done as quickly as possible.
Ted, you sound like an industrial-strength sort of guy. Actually if I can't make something smaller work I might have go the compressed air tank route. You were lucky to find a void that it fit perfectly.
1 More Mile! said…
Be careful of under inflation on rocky terrain with regular highway tires as the sidewalls are punctured easily.
1 More Mile!, good point about the sidewalls. So far I've only lowered the pressure from 55 to 35 psi. That's enough for a nice big flat contact spot on the road.

By the way, I compliment you for having thick skin. It must challenge you to read a guy who has the anti-motor prejudices that I do.
1 More Mile! said…
Boonie, I rode bicycles relentlessly when I lived in a locale that provided safety for that method of exercise. Unfortunately, I do not have that safety in my present locale and have replaced the bike with a lot of walking which i also enjoy.

I am heading off to the Bonneville Sped Week event later this month - true "gearhead nirvana". Posts to follow in my blog! Maybe the spectacle could convert you?
Anonymous said…
This should give you plenty of hot air to inflate your tires.