Deflating Tires for Unimproved Roads

[chin_k]

I got a 12V dual-head compressor from Costco, and I wonder if it is any good. I probably should get a better unit, but it was pretty cheap.

[Scott]

Fun discussion. Personally, I always start by clearly identifying the device's purpose (I mean, don't we all?). In order of capacity (x CFM @ y PSI), it would be (1) topping up, (2) radical deflate/inflate for off roading, and (3) running pneumatic tools. If it's #1, I really wouldn't spend too much money because even the poorest little compressors can get you out of a bind, and if you have bigger problems, then you're going to a tire shop anyway. Also, how often are we topping up (poll*)?. #2, I'd go with a compact 120V unit for the reasons already discussed. #3 is not really likely, especially with the lithium batteries/brushless motors/pure awesomeness of today's portable tools, but if you must have a pneumatic impact gun or die grinder, then a dedicated 120V compressor with a large tank would be my choice; I'd probably mount it to the chassis up under the passenger side (sooo much room unused!) and add a dedicated breaker.

* If we do a poll on how often we're topping up our tires, I'd like to see if there's a discernible difference between steel and aluminum wheels.

I'll go first. I've added a total of 20 lbs between six tires over the course of over two years and 25k miles. I have factory original steel wheels, rubber valve stems (don't laugh), and blow thru valve caps. I do not obsess over tire pressure as long as they're not low. I like between 50 and 60 in my Laufenn XT all terrains. This is the best of any vehicle I've owned, but this is the only one I've had with steel wheels

[pdemarest]

Hey Scott - funny you would mention mounting your compressor under the rig. Just yesterday I was under mine to look for a places to mount one (and also for the spare tire - but no space for it that I could see).

I've aired down about 3 times and wish I had done it more. The problem with finding a gas station with a working air pump is only part of the problem. The other part is that if you find one you now have 6 tires to fill and the hose is never enough so you have to turn the rig around to get to all 6 tires and then you have the additional issue of hogging the air/water station that others may be waiting to use. There are trips where I would not bring a compressor because I'm not going on any sketchy roads but even paved roads can be brutal. The road that runs from Organ Pipe Cactus National Monument along the Mexican border is paved but apparently it was done before the Civil War as it is a continuous string of potholes and washouts.

On a totally different topic I just got a call from the guy who is going to install some laminate flooring in my Chinook. The material I picked was on back-order and they said it might not come in time for my Yellowstone trip but it arrived today so I'll be dropping it off on Monday. Let me know if anyone out there would like some of the beautiful harvest gold semi-shag carpet that will be removed!

[Blue~Go]

I have probably "topped off" about 8 psi total over four-and-a-half years in the main tires. So basically nothing. I topped off my spare a few times back in the day, but that was with the original spare and a rubber stem. Now that I have one of my Michelins there and a solid stem, it doesn't change much.

But I have used a compressor on tires. When?

1) The aforementioned minor topping off.
2) Adding air when I'm towing (because more weight on the rear axle).
3) Filled one of my car tires when I found a piece of metal stuck in it way out in the back of beyond.

I've also removed air (obviously a compressor not needed). When?

1) Done towing, put rear tires back to "normal weight" psi level
2) Get new tires back from Discount Tire; let out the extra 50 psi they put in

So on the one hand do I really need a compressor? Maybe not as I haven't used one very often. But then I've never used my spare tire, and I still carry that. But then you could carry spare pistons too, so you have to stop somewhere

I think for me it will be just convenient enough that I'd like to carry one. If I use it to air down/up on a long washboard road that would likely be priceless (currently I just avoid those, which may be a fine strategy). And if I never use a gas station air dispenser again I will not be the least bit unhappy. So yeah, I like the feeling of having one, when I think about it. If I ever get around to removing the generator that I never use (talk about carrying things I don't need ), I'll have plenty of room, too

On the other hand, clearly it's not a necessity.

[Scott]

Hey Scott - funny you would mention mounting your compressor under the rig. Just yesterday I was under mine to look for a places to mount one (and also for the spare tire - but no space for it that I could see).

Hi Paul, I posted a pic in the spare tire thread. That's where I'd consider mounting it. Or, if I was going with a compact 12V type, I'd probably put it where the old house battery was under the hood.

[ltg]

My Glacier requires topping off the tires more often than what other posters have stated. I really do not know why. It may be because I have alloy wheels, or maybe because I live in central Texas which has large temperature swings, or maybe because I am more anal about tire pressure. The real axle weights on my Glacier are right under the GAWR. With the tire gauge I use with its +/- 2% accuracy, when I air up the rear tires at 78 PSI, I am somewhere between 76.4 and 79.5. The maximum pressure on my tires is 80 PSI. At 75 PSI I am at the PSI for the load I am carrying. So, at a loss of 2 PSI I could be under inflated. I realize that most on this forum have the E350 chassis and my issues may not be very relative.

[pdemarest]

Hey Scott - saw that post this morning and responded. As you can see, I have spare tire "issues".

[Blue~Go]

Larry,

I'm persnickety about my tire pressures, so the reason I don't typically add air is that they don't lose any. I have Ford steel rims and one-piece extended metal valve stems.

Do you have the "fabric" (rubber?) valve extenders? I have read that they can leak air. I added the extended metal stems not long after getting the Chinook (which came with the "fabric" extenders) so I can't really compare to what it was like with them (except that it's a lot nicer checking them!).

[ltg]

I do not have any valve stem extenders. I have the regular rubber High pressure valve stems, about 1 1/2 inch long. I do have alligator flow thru valve caps on the inside dual wheels. My front and outside rear rims are alloy Eagle rims. My rear inside rims are steel.

Larry
2005 Glacier

[Blue~Go]

Okay, interesting. I wonder if the rubber stems can "seep" slightly (?). I have the "air through" caps as well, on all seven tires (but no rubber stems). Alloy rims: nice!