I have been airing down for over 13 years of wheeling trips now. It used to be by grabbing a coin, a stick, or anything nearby to let the air out of the valve. Lately I have found it much quicker to remove the valve stem core with a core remover but you still have to keep checking to see if the pressure is close to what you want it to be. Ever since I heard of the auto deflators I have wanted to try them out. I finally decided to get a set from Oasis, since I have inquired in the past and they have always been prompt at replying to my emails. The kit comes complete with a leather pouch, adjusting allen wrench, air pressure gauge, directions, sticker, and a handy air down sheet to find out an approximate pressure to run. Since tires are all different (Bias/Radial/etc) the guide is just an approximation but it is a handy guide to have! I found that the deflator is a great tool, BUT you have to be aware of some things! - They are NOT compatible with EQUAL! If you remove the Equal from your tires be sure to thoroughly blow out all residue!
- The same deflator on two tires CAN give different results - best to change the cores to new ones when getting the deflators.
- For some reason the rubber valve stems seem to work better than the steel ones (higher flow rate?).
| | | | The deflater threaded on with the allen adjusting wrench in place | tire pressure chart provided | the four tire pressure gauges used for comparison | I reached in my drawer and grabbed 3 tire pressure gauges and tested the pressure with the 3 I had, and the one that came with the kit. You can see the results below with a 20-40psi range deflator. Tires like my TSL's need a lower setting like the 2-8 psi ones which I now have. Before threading them on I read the directions that stated adjusting the allen head all the way out (flush with the deflator) would be the lowest setting so that is where I put them. I checked them all on a flat table to see that they were set the same. A few hissed and a couple did not, I figured this was ok since they weren't at exactly 20psi. | initial tire gauge readings.. | 24 hours later I came to check on them and found 2 tires completely flat (both rears), passenger side front was at 17psi and the drivers side was at... 20psi. So, one out of 4 did that job. After finding this I figured the only difference between front and rear is that the rear has EQUAL balancer in them, and the front does not. The 3psi difference is as a result of the valve cores believe it or not. If I switch the deflator from the 17 psi to the 20 psi tire, the pressure does not change. It is not a good idea to leave the deflators on in case there is a small leak. When I put them on the front they worked great and I could probably leave em on for weeks but once a deflater gets a little dirty it may leak. I contacted John about the flat tires and he was very imformative - this is what he had to say (I couldn't remember the name of the powder stuff).. | Yeah, it's called Equal. Our deflators are absolutely incompatable. One of my customers tipped me off last year. Said he'd been using our deflators for years and loved them, put Equal in his tires and had
problems. So we did our own test. Sure enough, that special valve core with the little "filter" screen on it will not prevent material from contaminating our valve seat, and the screen loads up with material promptly which reduces the flow rate to almost nothing while deflating if you're driving. Even while deflating via conventional means, the flow rate is very much less than a standard valve. Other than that, we love the stuff. I searched for alternatives to their filter valve core, but found none that were practical.
An alternative to Equal is 1/2" dia polyethelyne balls, about 2 oz worked for my 35x12.50R15 MTR's. 4 oz was too much, and the tire would bounce on deceleration. It is much cheaper than Equal to boot. I think 3/8 balls might be more appropriate, but have had no more time to persue testing.
The1/2 balls are still in my tires to this day, and I love it. Standard valves, no conflict with our deflators, no more balancing. BB's would
probably work too, but could be a little noisy. Hell, truckers have used everything from sand to golf balls for decades. -John
| | | Tire #4 after 24 hours (with EQUAL) | Tire #3 after 24 hours (with EQUAL) | After getting the 2-8 psi deflators I threaded them on (front tires only, no EQUAL) and they dropped from 20 psi to 5 psi in about 5 minutes, once again with a slight variation as a result of the valve cores or something inherent to the tires. According to John at Oasis | Per our instruction manual, we do not recommend they be left on for more than 60 minutes, because if there is a minute leak, this could happen.
They were never intended to be left on. Now, I have personally tested them in the past on my own vehicle, and left them on for as much as 72 hours on a camping trip, four wheeling during the day and camping at night, and not lost even 1/2 psi in the past. We make the one hour recommendation based on: 1) the chance that the valve seat may have gotten dirty and 2) there is little point to leaving them on after they've finished deflating anyway. Most leaks are due to foreign material in the valve seat. We test them thoroughly before we accept them, with an extremely sensitive flow gauge at the top, bottom, and middle of their range. This flow gauge is sensitive enough to indicate a leak that is inaudible, in which case the deflator is rejected from test. Also per our instructions, keep good valve caps on your valves when not deflating. If any dirt gets into your valve core, guess where its going to go when you put the deflators on - right into the valve seat. If you ever lend them to someone, ask them to give their valve stems a quick spurt by hand before putting the deflator on to expel any dirt that may be in there. With reasonable precaution, they should only have to be cleaned about once every two years. Cleaning is a maintenance issue, not a warranty issue. And they tend to get better as they age. The ball valve is rubber
(Buna-N), and as time goes on it conforms to the valve seat. Also per our instructions, they are sensitive to flow rate. If you have
have one tire that comes down to a different pressure than the other three, it's valve may have a faster or slower flow rate than the others. To prove whether this is the case, here is the test: use one deflator on all four tires, if it comes down to different pressures, it's a flow rate issue.
You have two choices: adjust each deflator to a particular tire and mark it LR, RR, etc, or better, go down to Pep Boys and get four new valve cores all from the same package. This is usually sufficient to make all valves flow at nearly the same rate, and renders the deflators interchangeable. | |
Home 
News & Reviews 
