Hydraulic air compressors utilize a crane truck’s existing hydraulics as a power source for the compressor and can be an excellent choice for mobile service vehicles. Hydraulic air compressors are available with either rotary screw or reciprocating compressor technology in a range of CFM outputs with varying GPM requirements.
When choosing a hydraulic air compressor, it’s vital to consider abovedeck vs. underdeck, rotary screw vs. reciprocating, air output, hydraulic requirements, and size and weight considerations. We discuss these considerations further after the comparison chart below.
Let’s look at the most popular hydraulic air compressors in North America. When reviewing the chart below, keep in mind there is a direct correlation between hydraulic flow (GPM) and air output (CFM); vehicle upfits capable of the high GPM range will produce a high CFM output, and vice versa.
| Model | Style | Compressor Type | Air Output | Hydraulic Flow Required | Weight | Size |
| VMAC H40 | Abovedeck | Rotary Screw | 25-40 CFM | 9-12 GPM | 150 lb | 4.125 ft³ |
| VMAC H60 | Abovedeck | Rotary Screw | 40-60 CFM | 14-21 GPM | 160 lb | 4.125 ft³ |
| Boss BA440 | Abovedeck | Rotary Screw | 30-40 CFM | 8-12 GPM | 163 lb | 4.718 ft³ |
| Boss BA870 | Abovedeck | Rotary Screw | 70 CFM | 18 GPM | 270 lb | 8.985 ft³ |
| Boss Infinity 35 | Abovedeck | Rotary Screw | 20-35 CFM | 7.75-13.25 GPM | 200 lb | 7.055 ft³ |
| Boss Infinity 80 | Abovedeck | Rotary Screw | 45-80 CFM | 10.7-17.8 GPM | 300 lb | 7.931 ft³ |
| Vanair Reliant RC40 | Abovedeck | Rotary Screw | 30-40 CFM | 9.5-12 GPM | 408 lb | 9.892 ft³ |
| Vanair Reliant RS45 | Abovedeck | Rotary Screw | 30-45 CFM | 7-11.2 GPM | 195 lb | 9.785 ft³ |
| Vanair Reliant RS85-L | Abovedeck | Rotary Screw | 60-85 CFM | 14-19.9 GPM | 285 lb | 11.544 ft³ |
| BOSSAIR H85 | Underdeck | Rotary Screw | 35-85 CFM | 8.1-18.2 GPM | 425 lb | N/A |
| Vanair UDHD | Underdeck | Rotary Screw | 60-85 CFM | 17-23.5 GPM | 428 lb | N/A |
Hydraulic air compressors come in two styles: abovedeck and underdeck. As expected, abovedeck air compressors are installed above the vehicle's deck, while underdeck air compressors get mounted beneath the vehicle's deck.
Most hydraulic air compressors are abovedeck as these designs are straightforward, cost-effective, and easy to install. Abovedeck air compressors offer enough air power for most pneumatic tools, making them an effective solution for most mobile mechanic applications.
Underdeck hydraulic air compressors can produce higher air output for specialized applications, but installation is significantly more complex. Underdeck air compressors arrive as a medley of components and require a skilled upfitter to identify the ideal implementation, source missing components, and install the compressor. For this reason, most people who are considering hydraulic air compressors prefer abovedeck solutions.
Two types of air compressors are used in mobile applications: rotary screw and reciprocating. While both compressor types produce compressed air, their similarities end there.
Reciprocating, or piston, air compressors use pistons to force air into a smaller space. These pistons move up and down, creating a pause in air production on every upstroke. Because of this intermittent compression, reciprocating air compressors require an air receiver tank to accumulate and store compressed air before you can use it.
Meanwhile, rotary screw air compressors use spinning rotors to trap air and compress it into a smaller space. Because rotary screws spin continuously, air production is constant and compressed air is generated as quickly as it is consumed. An air receiver tank is not required, and air is available on demand.
For applications where time is money, rotary screw air compressors are the ideal option.
Once you know your air compressor type and style, it's time to nail down your air output requirements. Air compressors are rated by the amount of air they deliver using CFM, an acronym for Cubic Feet Per Minute. CFM outputs vary by tool; larger tools typically require higher CFM.
Small tools like ½" impact wrenches, ¼" ratchets, and air hammers are served well by 30-40 CFM air compressors. Meanwhile, larger tools like 1" impact wrenches, vertical grinders, and 60 lb pavement breakers often need closer to 60 CFM.
However, tool requirements vary, so additional research may be required to identify your air needs. To find out how much air your tools likely require, check out our Air Tool Consumption Guide.
Not all hydraulic air compressors are created equal, and the best mobile compressors on the market prioritize a compact, lightweight design.
Choosing a lightweight air compressor means you'll be able to add more tools and equipment to your truck, carry more materials, or take advantage of better fuel economy. Meanwhile, compact air compressors free up space for other tools, equipment, and materials and keep trucks looking sleek and professional.
VMAC's hydraulic driven air compressor are the best choice for fleet managers and owners looking for a compact, powerful and lightweight hydraulic abovedeck air compressor that can operate in any climate.
Learn more about VMAC's 40 CFM and 60 CFM hydraulic air compressors.