Over the years I have tried all of the latest accessories to speed the task of air-down. Trying to find a valve core stem in the sand is not the way to start the day. I can think of better things to do than kneeling in the mud with a screw driver tip holding the valve stem in.
Then, along came automatic deflators that screw on to the valve stem. While they work, it does take timing to achieve the correct pressure. But, that was the early models. Staun has developed a deflator that works; screw it on and it stops at a pre-set level.
Okay, I had read about them. I won a set in a raffle once. They stayed in the console while I used my favorite home-brew hose connection to air-down two tires at a time. One morning while reaching for my air gauge, I grabbed the little pouch of deflators. Well, why not try them?
Installation was simple - remove valve cap, screw deflator on valve stem; repeat for each wheel.
First, a description of the Staun deflators. They are a brass body that screws on to the valve stem. Internally, they have a valve that is adjustable and pressure sensitive. The adjustment is loosening a knurled retainer and screwing the pressure sensitive valve in or out to achieve the desired pressure. When the adjusted pressure is reached, the valve automatically closes. As long as there is about a ten pounds pressure difference between the tire and the level setting, the deflating will begin automatically and continue until the desired pressure is reached. If deflating does not beginning automatically, there is a stem that can be pulled to start the process.
My first time using them I was not sure of the pre-set pressure level. I did install all the deflators and waited a couple of minutes to check the pressure. By guess, I reached 18 pounds and figured that was sufficient for the trail.
Later, I did some timed testing to determine the pre-set pressure and how long it would take to reach that level. Beginning with a tire (LT295/75/R16) inflated to 30 pounds, it was deflated to the pre-set value of 15 pounds in 3 minutes and 45 seconds.
Overall, I find the Staun deflators to be a worthwhile accessory for the toolbox. The deflators come in a leather pouch and are easy to store. Basically, you can go from street pressure to trail pressure in less than five minutes.
For more information, visit Staun Products.