Selecting the Right Scissor Hoist for Your Dump Trailer Leave a comment
Choosing the right hydraulic scissor hoist for a dump trailer starts with more than a ton rating. Dump-body length, rear overhang, desired dump angle, load placement, mounting geometry, trailer ratings, and the kit components you already own all affect the correct choice.
This guide compares the complete Dexter Power Hoist lineup offered by Johnson Trailer Parts—from the compact PH310 for 8’–10′ dump beds through the PH630 for 18’–24′ beds—and explains how to choose between Hoist Only, Standard, Pro, and Pro Max packages.
Visit the Johnson Trailer Parts YouTube channel for additional dump-trailer, hydraulic-hoist, and trailer-build videos.
Dexter Power Hoist Model Comparison
Use dump-bed length to narrow the choices, but do not select a model from bed length alone. Models serving the same bed range provide different lifting capacities, cylinder configurations, pump-reservoir sizes, and installation geometry.
← Swipe left/right to see the full table →
| Model | Rated Hoist Capacity* | Recommended Bed Length | KTI Reservoir | Available Packages |
|---|---|---|---|---|
| PH310 | 3 ton / 6,000 lb | 8’–10′ | 3 quart | Hoist Only, Standard, Pro |
| PH416 | 6 ton / 12,000 lb | 10’–14′ | 3 quart | All four |
| PH516 | 8 ton / 16,000 lb | 10’–14′ | 3 quart | All four |
| PH520 | 10 ton / 20,000 lb | 12’–16′ | 3 quart | All four |
| PH616-5 | 8 ton / 16,000 lb | 12’–16′ | 3 quart | All four |
| PH616-6 | 11 ton / 22,000 lb | 12’–16′ | 6 quart | All four |
| PH621-5 | 8 ton / 16,000 lb | 16’–20′ | 3 quart | All four |
| PH621-6 | 11 ton / 22,000 lb | 16’–20′ | 6 quart | All four |
| PH625 | 12 ton / 24,000 lb | 16’–20′ | 6 quart | All four |
| PH630 | 12 ton / 24,000 lb | 18’–24′ | 6 quart | All four |
*The advertised tonnage is a hoist capacity rating when properly applied. Actual published capacity changes with body length, rear overhang, and dump angle. It is not the trailer’s GVWR or allowable payload.
Quick Selection by Dump-Bed Length
- 8’–10′: PH310
- 10’–14′: PH416 or PH516
- 12’–16′: PH616-5, PH520, or PH616-6
- 16’–20′: PH621-5, PH621-6, or PH625
- 18’–24′: PH630
Where multiple models serve the same bed range, compare the published chart capacity at your actual geometry. A higher advertised tonnage does not automatically make a model correct if its dimensions or mounting position do not fit the trailer.
How to Select the Right Dump-Trailer Scissor Hoist
Step 1: Measure the Dump Body
Measure the body itself from the front of the dump floor to the rear edge. Do not use the trailer’s overall length, tongue length, or axle spacing. This measurement is dimension A in the Dexter capacity charts and determines which model families should be considered first.
Step 2: Measure Rear Overhang and Choose a Dump Angle
Rear overhang is the distance from the rear hinge pivot to the rear of the dump body. It changes the leverage acting on the body and is a required input in the published capacity charts. Common chart examples use 12″, 18″, and 24″ overhangs.
The desired dump angle also matters. A 45° angle generally provides more published lifting capacity, while a 50° angle may help sticky or compacted material release but normally reduces rated capacity. The hoist mounting distance shown in the dimensional drawing also changes with the selected angle.
Step 3: Estimate the Weight the Hoist Must Raise
The hoist raises the dump body plus the material in it. Begin with the completed body’s weight, add the intended cargo, and consider how that cargo will be distributed. A load concentrated toward the front of the body places more demand on the hoist than the same weight distributed evenly.
Dexter’s published charts assume a water-level, non-diminishing load, at least 3″ of vertical height between the rear hinge pivot and the floor, and hydraulic relief pressure set at 3,200 PSI. Loads that pile toward the front, stick to the floor, freeze in place, or otherwise do not behave like the published assumption can require substantially more lifting force.
Step 4: Use the Model Capacity Chart and Dimensional Drawing
After narrowing the models by bed length, locate the row matching your body length and rear overhang, then read the capacity under your planned 45° or 50° dump angle. Next, review the model’s dimensional drawing to confirm the collapsed size, mounting width, mounting distance, under-bed clearance, and potential interference with the frame, crossmembers, axles, plumbing, wiring, and other components.
PH520 Example: Why Geometry Changes Capacity
For a 14′ dump body, the PH520 chart publishes the following reference capacities:
← Swipe left/right to see the full table →
| Body Length | Rear Overhang | 45° Capacity | 50° Capacity |
|---|---|---|---|
| 14 ft | 12 in | 8.6 tons | 7.8 tons |
| 14 ft | 18 in | 9.3 tons | 8.5 tons |
| 14 ft | 24 in | 10.3 tons | 9.3 tons |
The same PH520 produces different published capacities as rear overhang and dump angle change. This is why selecting a hoist by its model name or advertised tonnage alone is not enough.
The PH520 example above demonstrates how body length, rear overhang, and dump angle affect lifting capacity. Each Dexter Power Hoist model has its own capacity chart and dimensional drawing.
Select a model from the comparison table above to view its complete capacity and installation-reference information, or review the complete Power Hoist installation manual to compare the published charts for every model.
Choose the Right Hoist Kit Variation
Once the hoist model is selected, choose the package that matches the components already on your trailer and the features you want. Select the variation on the product page before adding the kit to your cart.
← Swipe left/right to compare all kit options →
| Included Component | Hoist Only | Standard | Pro | Pro Max |
|---|---|---|---|---|
| Scissor Hoist Assembly | ✓ | ✓ | ✓ | ✓ |
| Mounting Brackets | ✓ | ✓ | ✓ | ✓ |
| Matched KTI 12V Hydraulic Pump | — | ✓ | ✓ | ✓ |
| Hydraulic Hoses & Fittings | — | ✓ | ✓ | ✓ |
| 15′ Three-Button Wired Remote | — | ✓ | ✓ | ✓ |
| Battery Cables & Electrical Components | — | ✓ | ✓ | ✓ |
| Safety-Arm Assembly | — | ✓ | ✓ | ✓ |
| Dump-Bed Hinges | — | ✓ | ✓ | ✓ |
| Single Dexter Power Jack Add-on Kit | — | — | ✓ | — |
| Dual Dexter Power Jack Add-on Kit | — | — | — | ✓ |
Hoist Only: Best for builders who already have a compatible hydraulic system.
Standard: The most common choice for new builds and complete hoist replacements.
Pro: Adds powered tongue lifting and leveling with one Dexter Power Jack.
Pro Max: Adds dual synchronized Dexter Power Jacks for increased front lifting stability.
PH310 exception: The smallest model is offered in Hoist Only, Standard, and Pro packages; a Pro Max variation is not offered.
How the Pro and Pro Max Shared-Pump Systems Work
Pro and Pro Max packages operate the Dexter Power Jack system from the same KTI hydraulic power unit used by the dump hoist. An inline selector valve directs hydraulic flow to either the hoist or the jack system. The functions operate independently, one at a time, avoiding a second hydraulic pump, motor, control, and set of battery cables.
- Pro: Includes the Single Dexter Power Jack Add-on Kit with an inline selector valve.
- Pro Max: Includes the Dual Dexter Power Jack Add-on Kit with an inline selector valve and hydraulic flow divider for synchronized jack operation.
Hoist Capacity Is Not Trailer GVWR or Payload
The completed trailer’s GVWR and legal payload are determined by the complete system, including the frame, axles, suspension, brakes, wheels, tires, coupler, hitch, and every other rated structural component.
For example, a trailer with a 14,000 lb GVWR and a completed empty weight of 4,000 lb has approximately 10,000 lb of payload before considering any other limits. A hoist chart showing capacity above that amount does not increase the trailer’s allowable payload.
Never exceed the trailer’s GVWR, gross axle weight ratings, tire ratings, coupler rating, hitch rating, or tow-vehicle limits. Hoist selection and trailer weight ratings are related safety checks, but they are not interchangeable ratings.
After Choosing Your Hoist: Installation and Hydraulic Setup
This section is a planning reference, not a substitute for the complete Power Hoist and KTI installation instructions. Read the manuals before installation and follow all model-specific dimensions, mounting procedures, pressure settings, wiring guidance, and safety instructions.
Hydraulic-System Reference
- Maximum working pressure: 3,200 PSI
- Maximum hydraulic flow: 2 GPM
- Double-acting lowering pressure: 1,500 PSI
- Hoist hydraulic ports: #6 JIC
- Complete-kit operation: Power up, power down, and gravity down
Hydraulic Fluid and Battery Cables
KTI recommends premium anti-wear hydraulic fluid and warns against mixing different hydraulic fluids. Fluid viscosity must suit the operating temperature. The pump manual lists ISO 15 for approximately -20°F to +32°F and ISO 22, ISO 32, or Dexron III ATF for approximately +14°F to +120°F.
Battery-cable size must increase as the distance between the battery and hydraulic power unit increases. Undersized cables can cause voltage drop, raise motor amperage, slow pump performance, and damage electrical components. Follow KTI’s cable-sizing chart rather than selecting cable by appearance alone.
View KTI battery-cable sizing reference
| Cable Length | Recommended Size |
|---|---|
| 1–2 ft | 4 AWG |
| 3–4 ft | 2 AWG |
| 5–7 ft | 1 AWG |
| 8–9 ft | 1/0 AWG |
| 10–12 ft | 2/0 AWG |
| 13–15 ft | 3/0 AWG |
| 16–19 ft | 4/0 AWG |
Initial Hydraulic Bleeding
After installation, KTI specifies a staged cycle to remove air: raise the cylinder approximately one-third and lower it fully, raise it approximately two-thirds and lower it fully, then raise it through its full stroke and lower it fully. Monitor the reservoir for aeration, keep it above half full during operation, allow foamy fluid to settle, and repeat the process if necessary.
Essential Raised-Body Safety
- The supplied safety arm supports an unloaded body only.
- Never position yourself beneath a raised, loaded dump body.
- Never use the safety arm to support a loaded body.
- Never shock or jerk a raised body to dislodge a stuck load. Lower the body and free the material safely.
- Protect brake lines, wiring, hydraulic hoses, and nearby components from mounting and welding damage.
Manuals and model resources: Review the complete Power Hoist installation manual and the KTI single/double-acting power-unit instructions before installation.
Battery Maintenance Tip
Dump-trailer hydraulic pumps place a heavy demand on the battery. Keep the battery fully charged, inspect cable connections regularly, and consider an onboard charger or solar maintainer when the trailer sits between uses. Browse compatible trailer battery chargers and solar maintainers.
Frequently Asked Questions
What size scissor hoist do I need for my dump trailer?
Start with the dump-body length, then compare models using rear overhang, desired dump angle, completed body and cargo weight, load placement, mounting space, and the published capacity chart. Do not select a hoist by its advertised ton rating alone. Trailer GVWR and component ratings must also be checked independently.
How do I measure dump-body length and rear overhang?
Measure dump-body length from the front of the dump floor to its rear edge; do not include the tongue or use the trailer’s overall length. Measure rear overhang from the rear hinge pivot to the back of the dump body. These are dimensions A and B, respectively, on the Dexter capacity charts.
Why does published hoist capacity change with bed length, rear overhang, and dump angle?
Those dimensions change the leverage acting on the dump body. A longer body, different hinge-to-rear overhang, or steeper dump angle changes the force required at the hoist. The same hoist can therefore have several published capacities depending on the installation geometry.
Is hoist capacity the same as trailer GVWR or payload?
No. Hoist capacity describes lifting performance under specified application conditions. Trailer payload is limited by GVWR minus the completed trailer’s empty weight and may be further restricted by axles, suspension, brakes, tires, wheels, frame, coupler, hitch, or other components.
Should I choose a 45° or 50° dump angle?
A 45° angle generally provides more published lifting capacity. A 50° angle may help certain materials release, but capacity is usually lower and the required mounting distance changes. Choose based on the material, capacity chart, dimensional drawing, and complete trailer design.
What is the difference between Hoist Only, Standard, Pro, and Pro Max?
Hoist Only provides the scissor-hoist assembly and mounting brackets for a builder who already has a compatible hydraulic system. Standard adds the matched KTI pump, hydraulic and electrical components, safety arm, and dump-bed hinges. Pro adds a single Dexter Power Jack and selector valve. Pro Max adds dual Dexter Power Jacks, a selector valve, and a hydraulic flow divider. The PH310 is not offered in Pro Max.
Does Hoist Only include a hydraulic pump?
No. Hoist Only is intended for builders who already have a compatible hydraulic system. The KTI pump, control, hoses, fittings, and related electrical components are included with applicable Standard, Pro, and Pro Max packages, not with Hoist Only.
PH516 versus PH520: which hoist should I choose?
The PH516 is an 8-ton-class hoist commonly considered for 10’–14′ dump bodies, while the PH520 is a 10-ton-class hoist commonly considered for 12’–16′ bodies. Where their applications overlap, compare both models using your actual body length, rear overhang, dump angle, required lifting capacity, mounting dimensions, and available under-bed space. The higher advertised ton rating does not automatically make the PH520 the correct fit. See our detailed PH516 versus PH520 dump-trailer hoist comparison.
What do power-up, power-down, and gravity-down mean?
Power-up uses the hydraulic pump to raise the dump body. Power-down uses hydraulic pressure to lower it. Gravity-down allows the body’s weight to return it without running the pump motor during lowering. Applicable complete Dexter Power Hoist kits support power-up, power-down, and gravity-down operation; follow the supplied hydraulic and control instructions for the selected setup.
Why won’t my dump bed lift a heavy load?
Begin with the battery state of charge, cable size and connections, hydraulic-fluid level, hose routing, pump operation, pressure and relief settings, and any binding or interference. Then verify that the load weight, placement, body length, rear overhang, and dump angle remain within the model’s published chart. Never work beneath a raised body without following the manufacturer’s unloading and support instructions, and never adjust hydraulic pressure beyond the published specification.
Need Help Choosing the Right Scissor Hoist?
Johnson Trailer Parts can help you compare bed length, rear overhang, dump angle, capacity-chart results, model dimensions, KTI pump packages, Dexter Power Jack upgrades, and freight-delivery requirements.
- Dump-body length and width
- Rear overhang from hinge pivot to the back of the body
- Desired 45° or 50° dump angle
- Completed dump-body weight and intended maximum cargo
- Trailer GVWR, axle ratings, and intended application
- Whether you need Hoist Only, a complete hydraulic kit, or Power Jack upgrades
Call or Text: (602) 292-9690
Email: sales@johnsontrailerparts.com
