Sullair 185 Towable Compressor Performance

[MikePhua]

The Sullair 185 is a compact and highly durable towable rotary-screw compressor. It delivers around 185 cfm of compressed air at a standard operating pressure of 100 psig (7 bar) and handles a range between 80 to 125 psig (5.5 to 8.6 bar) .

Manufacturer Roots
Founded in 1965 in Indiana, Sullair was a pioneer of rotary-screw compressor technology in the U.S. Today, as part of Hitachi, the company continues to produce portable air power units famous for their performance and longevity .

Pressure Range Explained
A rated pressure of 100 psig refers to the benchmark output of the compressor. It's common to operate within an extended range—80 psig on the low end, valuable for light tool applications, and up to 125 psig for demanding tasks that require higher delivery pressure .

Recommended Operating Practices
Air system experts generally advise using only about 70% of a compressor's maximum free-air delivery to preserve longevity. For the 185, optimizing performance means running near 130 cfm, rather than at full rating, especially for continuous applications .

Towing and Mobility Insights
The unit is hill-designed for mobility. Models with running gear (DPQ package) weigh around 2,175–2,275 lb (~990–1,030 kg) and feature independent torsion-suspension axles with axle ratings near 3,700 lb. This allows towing speeds up to 55 mph (89 kph), although users must tow within the rated limits for safety .

Operator Story
On a rugged mining site, team members replaced older units with a modern Sullair 185. They observed that dialing back pressure to 90 psig boosted actual airflow into hammer tools—more throughput and reduced lag during startup. The lower pressure reduced wear on downstream hoses too, improving uptime.

Usage Recommendations

• For extended tool use, set pressure at about 85–95 psig for better airflow while maintaining motor efficiency.
  
• Watch the pressure gauge and modulate flow so the compressor isn't pushed at full capacity during long cycles.
  
• Confirm towing components—chains, jack, hitch—comply with weight limits; misuse can lead to failure or injury.
  

Technical Term Clarification

• cfm (cubic feet per minute): A volume measurement of airflow delivery—a higher value suggests faster tool performance.
  
• psig: Pounds per square inch, gauge—reflects pressure above ambient air, critical for pushing tools effectively.
  
• Free-air delivery: The actual air output under operating conditions; typically 70% of the machine’s maximum rating in the field.
  
• Torsion-suspension axle: Independent wheel suspension that smooths road transport, reducing stress on the frame.
  

Summary
The Sullair 185 towable compressor excels because of its adaptable pressure range (80–125 psig), robust design, and portable form. For sustained tool use, operating at around 70% of maximum pressure enhances airflow, reduces wear, and extends the compressor’s longevity. Ensuring safe towing practices and correct hitch setup keeps performance smooth and reliable.