VIAIR 400P Automatic 40045

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Who it fits · inflator

Best for: Daily drivers and roadside top-offs where portability and auto shut-off matter more than CFM.

Skip if: You regularly fill truck, trailer, or RV tires from flat, or you need published high-flow performance.

VIAIR VIAIR 400P Automatic 40045 is catalogued for buyers comparing tire-pressure gear by listing specs, price, and owner themes — not as a PumpGauge lab measurement.

For portable inflators, prioritize duty cycle, hose reach, and power source (12V vs cordless) over headline PSI. Owner notes about heat and battery drain matter more than marketing fill claims.

List pricing around $168 puts it in the serious kit range. Verify what you are paying for against a cheaper single-purpose alternative.

Listing highlight we keep as context (not our measurement): AUTOMATIC 12V AIR COMPRESSOR: The VIAIR 400P Automatic is a portable air compressor built for trucks, SUVs, Jeeps, RVs, and off-road vehicles with tires up to 35 inches. Its automatic pressure-control system and direct-drive gearless motor support convenient tire-to-tire transitions for daily maintenance, road trips, camping, overlanding, and trail use.

Listing highlights (cleaned)

Deduplicated manufacturer/retailer bullets. Promotional gift lines and repeated paste are removed. These are not PumpGauge measurements.

• AUTOMATIC 12V AIR COMPRESSOR: The VIAIR 400P Automatic is a portable air compressor built for trucks, SUVs, Jeeps, RVs, and off-road vehicles with tires up to 35 inches. Its automatic pressure-control system and direct-drive gearless motor support convenient tire-to-tire transitions for daily maintenance, road trips, camping, overlanding, and trail use.
• VERSATILE VEHICLE INFLATION: This automatic tire inflator works with trucks, SUVs, Jeeps, 4x4s, side-by-sides, RVs, motorcycles, bicycles, and compatible inflatables. Connect the heavy-duty battery clamps to a running vehicle battery, attach the press-on chuck, and use the trigger-style inflation gun to add or release air while monitoring pressure.
• COMPLETE PORTABLE KIT: This off road air compressor kit includes a 25-foot 5-in-1 inflator and deflator hose with an inline 100 PSI gauge, 8-foot power cord, three inflation tips, Presta valve adapter, aluminum I-Beam sand tray, thermal overload protector, 40-amp inline fuse holder, press-on tire chuck, and dual-compartment carrying bag.
• 150 PSI HIGH-AIRFLOW PERFORMANCE: This 150 PSI air compressor delivers a 2.30 CFM free-flow capacity and operates with a 33% duty cycle at 100 PSI. Powered directly by a 12V vehicle battery, this heavy duty tire inflator supports tires up to 35 inches, while its IP54-rated housing helps resist dust and water spray during outdoor use.

Alternatives & next steps

Compare related tools in our guides and compare section, or dial cold-tire PSI with the tire pressure calculator. Corrections: [email protected].