Product Review:
4Crawler Offroad's 2Air System Short Cuts

| Toyota Section | Toyota Reviews |

By: Joe Micciche December, 2001

This is my complete 2Air system, with storage bag, coiled hose, schraeder valve, and extra fittings.

Airing tires down for trail use, then airing them back up for the ride home, is one of the most important rituals 4-wheelers go through. The benefits of running the proper pressures for trail and street duty cannot be minimized: while tire and vehicle performance offroad depends on finding that sweet spot for the conditions, tire life and personal safety onroad also depend on tires inflated to the proper pressures. Various products cater to rapid deflation or inflation usually of just a single tire, but to date none have facilitated quick air down and air up of all tires to a single, safe pressure.

Roger Brown of 4Crawler Offroad has an innovative solution for those who want to air up and down rapidly. The 2Air/4Air systems make adjusting psi in 2 or 4 tires at a time a quick job, and the air systems also equalize pressure across the tires being adjusted. This means the driver can be certain all tires are optimized for the conditions without scurrying around to check each one; and air can be "recovered" from a spare or the other 3 tires to inflate a low or flat tire.

So what exactly is the 2Air/4Air system?

The central brass valve with the schrader valve fitting. One of the brass quick-release clipless valve stem chucks.

For this review, I opted for a 2Air system. While I air all four tires down to a single psi offroad, onroad I run very different pressures front and rear due to the weight distribution of my truck. Thus, I preferred to adjust two tires at a time as opposed to all four, and found the 2Air met my needs better than 4Air.

The 2Air/4Air systems are comprised of a central manifold for controlling the pressure adjustments - and beyond this, the systems can be configured in almost infinite ways and for any type of vehicle. The central air control valve can be fitted with a schraeder valve for standard service station type air chucks, a quick-disconnect air fitting, and an air gauge for monitoring pressure. Brass fittings with clips or clipless chucks can be used for the tire valve stem fittings. The option of "severe duty" fittings and hose for those in extreme climates is also available. Basically, 4Crawler can custom-build any type of air system based on your particular needs.

The central air control valve is the brain of this system. This type of air manifold has a valve which allows the operator to open the system to allow air in or out; or to allow the system to self-equalize with no air loss. This is extremely helpful when dealing with a low tire, a flat, or using a spare tire to fill a low/flat tire. In this case, a fitting can be provided for a fully-inflated spare to act as an air source. A spare inflated to 50 psi can provide 8 psi each to four tires aired down to 10 psi (to air them all up to 18 psi, including the spare); or the system can be rigged so the spare equalizes just a single tire.

Using the 2Air

I worked with Roger on my 2Air configuration, and the result is a system that works effectively and fulfills my needs. Attached to the central valve is a pressure gauge, and on the air inlet/outlet Roger supplied an optional quick-release schraeder valve. This configuration provides me with rapid and even deflation without the schraeder valve in place; and controlled, monitored inflation from any air source such as the service station pictured here. Most importantly, I can easily set my front tires to the desired psi, then do the rear tires - and since I have a rear Detroit Locker, I no longer worry about unequal side-to-side pressure and the effect that has on street driveability.

Using the system for either airing up or down is very simple. Lay the air lines out around the vehicle, leaving enough room for the tires to flatten out if airing down so the lines are not caught under them. I found it best to hook up the tire nearest the central valve first in case the central valve was open. Then place the remaining chucks on the wheel valves, and open the central valve to air down. While the system deflates the tires, you can do other last-minute things common when preparing to wheel. Be sure to periodically close the central valve and check the pressure, and always allow the system to stabilize a minute before checking pressure so that all tires are at the same psi and the gauge provides an accurate reading.

The clipless quick-release chuck on a valve stem. 2Air in place, ready to begin inflation of rear tires. Close the valve and allow the pressures to equalize before settling on the reading.


The 2Air/4Air system is a great convenience for 4-wheelers, in fact I've also found myself regularly using it on our cars in addition to off road. The system provides a great amount of versatility for getting proper, even tire pressures set in any condition; and for evening out a low tire offroad. 2Air allows me to set my tire pressures with confidence and not have to recheck periodically after driving to make sure tire pressure is optimal; and it also provides another tire recovery safety net offroad.

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