ARB twin is the gold-standard onboard air system, fast enough for big tires and runs ARB lockers without strain.
Onboard air lets you air down for traction and air back up at the trailhead, run air tools, and (for ARB Air Locker owners) actuate the lockers. The ARB CKMTA12 twin is the long-running benchmark — 6.16 CFM at 0 psi, 4 CFM at 30 psi, with a 100% duty cycle that won't thermal-cycle on a long tire fill.
Mounting locations on an XJ: passenger-side firewall, under the rear seat, in the cargo area, or under-hood in the air filter recess (with relocate). Wiring is heavy — direct-to-battery via a 60A circuit breaker is the typical install. Plumb to a small 1-2 liter tank for steady air pressure, with quick disconnects in the engine bay and at the rear bumper.
More budget-friendly alternatives: ARB single CKMA12, Viair 400P portable, MORRflate or Smittybilt twin for compressor-only use.
| Part | Vendor | Est. price |
|---|---|---|
| ARB CKMTA12 Twin Compressor | ARB | ~$700 |
| ARB compressor mounting bracket | ARB | ~$60 |
| 60A circuit breaker | Blue Sea Systems | ~$40 |
Written and maintained by an AZ wheeler and driveway wrencher. Always cross-reference your factory service manual — modifications affect vehicle safety and warranty. Work at your own risk.