The PF-516 and PF-520 are two of the most popular hydraulic scissor hoists in the Primary Mover lineup.
Because both hoists share many similarities, customers often ask:
"Should I choose the PF-516 or the PF-520?"
The answer depends on your dump body length, desired dump angle, lifting capacity requirements, and how you plan to position the hoist.
The most important thing to understand is that these two hoists are much more similar than most people realize.
The Biggest Misconception
Many customers assume the PF-520 has a larger cylinder and therefore produces more force.
That is not the case.
Both hoists utilize the exact same hydraulic cylinder bore:
- PF-516 = 5.5-inch cylinder bore
- PF-520 = 5.5-inch cylinder bore
Since hydraulic force is primarily determined by cylinder area and hydraulic pressure, both cylinders are capable of producing essentially the same lifting force.
The difference is not cylinder force.
The difference is stroke length.
Stroke Length Comparison
- PF-516 = 16-inch stroke
- PF-520 = 20-inch stroke
The PF-520 simply has four additional inches of cylinder travel.
Those four inches create a surprisingly large difference in how the hoist can be installed and how it performs.
What Does the Extra Stroke Do?
The extra stroke allows the PF-520 to open farther than a PF-516.
That additional travel creates two major advantages:
- More flexibility in hoist placement
- Greater potential dump angle
Because the hoist can open farther, it can often be mounted farther forward on the trailer while still achieving a desirable dump angle.
Moving the hoist farther forward generally improves lifting geometry and increases the effective lifting capacity of the system.
This is one reason the PF-520 is often recommended for longer dump bodies.
Why Does the PF-520 Cover Longer Trailers?
On our sizing charts, you will typically see:
- PF-516 = 10 to 14-foot dump bodies
- PF-520 = 12 to 16-foot dump bodies
These are intended as starting points rather than strict limitations.
There is no reason a PF-520 cannot be installed on a 10-foot trailer.
Likewise, there are situations where a PF-516 may work perfectly on a trailer larger than 14 feet.
These recommendations are based on years of testing and common geometry combinations involving:
- M-value
- Rear overhang
- Dump angle
- Typical payloads
The sizing charts simply help narrow down the best starting point.
The Trade-Off: Dump Cycle Time
Everything in hydraulic engineering involves trade-offs.
The PF-520's additional stroke creates additional capability, but it also requires more hydraulic oil volume.
If a PF-516 and PF-520 are installed on identical trailers with identical power units:
The PF-520 must travel an additional four inches before reaching full extension.
That means:
- More oil volume is required
- Cycle times are slightly longer
- The power unit runs slightly longer
For some customers, this difference is insignificant.
For others who cycle their trailers constantly throughout the day, it may matter.
Capacity vs Dump Angle
One of the biggest advantages of the PF-520 is flexibility.
The extra stroke allows you to choose how you want to use it.
You can:
- Move the hoist farther forward and gain lifting capacity
- Maintain similar placement and gain dump angle
- Find a balance between both
This is why the PF-520 often performs so well on longer dump bodies.
The additional stroke gives builders more options when optimizing geometry.
When Should You Choose a PF-516?
The PF-516 is an excellent choice when:
- You have a shorter dump body
- You want faster dump cycles
- You don't need additional stroke
- Your geometry already provides sufficient dump angle
For many 10 to 14-foot applications, the PF-516 is extremely difficult to beat.
When Should You Choose a PF-520?
The PF-520 becomes attractive when:
- You are approaching 14 to 16 feet in body length
- You want additional dump angle
- You need more flexibility in hoist placement
- You want additional lifting leverage through geometry
The cylinder itself is not stronger.
The geometry possibilities are stronger.
Final Thoughts
The PF-516 and PF-520 share the same 5.5-inch cylinder bore and generate essentially the same hydraulic force.
The major difference is the additional four inches of stroke found in the PF-520.
That extra stroke provides greater flexibility for dump angle, hoist placement, and lifting geometry.
For shorter dump bodies, the PF-516 often provides everything you need with faster cycle times.
For longer dump bodies, the PF-520 offers additional flexibility that can make a significant difference in overall performance.
Need help deciding between a PF-516 and PF-520? Call Primary Mover at 985-888-6554 and we'll help determine which hoist best fits your application.
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