Radflo 2.5 Hydraulic Bump Stop - 1-5/8” Shaft
6SB-001-00
The Radflo 2.5 Hydraulic Bump Stop is engineered for heavy vehicles and high-impact off-road suspension systems that need controlled bottom-out protection. Using velocity-sensitive damping, it acts as a secondary shock during the final inches of compression, progressively increasing resistance to absorb impact energy, reduce harsh bottoming, and protect the shocks, suspension mounts, chassis, and occupants from damaging loads.
Built around Radflo’s Freeflo® Racing Piston, a massive 1-5/8" chrome-plated alloy-steel shaft, CNC-machined bronze rod guide, and rebuildable multi-direction sealing system, this hydraulic bump stop is designed for extreme off-road use. Available with 2", 3", or 4" of travel, each unit is fully serviceable and tunable for rock crawlers, Ultra4 cars, desert trucks, prerunners, buggies, and other severe-duty suspension applications.
Includes:
- (1) Radflo 2.5 Hydraulic Bump Stop
- Universal spherical bearing
- Mounting hardware
Sold individually.
Specifications
| Specification | Details |
|---|---|
| Manufacturer | Radflo Suspension Technology |
| Product Type | Off-Road Hydraulic Bump Stop |
| Mounting Style | Pin Mount with Spherical Bearing |
| Body Diameter | 2.5" |
| Travel Options | 2", 3", or 4" |
| Shaft Diameter | 1.625" / 1-5/8" |
| Shaft Material | Mirror-Polished Alloy Steel |
| Shaft Finish | Chrome Plated |
| Body Material | SSID Alloy Steel Tube |
| Body Finish | Clear Cadmium Plated |
| Body Caps / Eyelets | CNC-Machined 6061 Aluminum |
| Body Cap Finish | Black Anodized |
| Rod Guide | CNC-Machined Bronze with PTFE Coating |
| Piston | Radflo Aluminum Freeflo® Racing Piston |
| Seal Design | Rebuildable Quad-Ring and Lip Seal Combination |
| Valving Type | Velocity-Sensitive Deflective Disc |
| Valving Adjustment | Self-Adjusting |
| Valving Tuning | Consumer or Factory Tunable |
| Suspension Fluid | Radflo High-Temperature, Foam-Resistant Fluid |
| Pressurization | Nitrogen Gas |
| Recommended Nitrogen Pressure | 200 PSI |
| Serviceability | Consumer or Factory Serviceable |
| Sold As | Individual Bump Stop |
Fitment
Universal Fitment for Custom Off-Road Suspension Systems
Common Applications:
- Rock crawlers
- Rock bouncers
- Ultra4 race cars
- Desert trucks
- Prerunners
- Off-road buggies
- Heavy trail rigs
- Custom tube chassis vehicles
Fitment Notes:
- Select 2", 3", or 4" travel based on available packaging space and suspension design.
- Mounting height and engagement point must be matched to total suspension travel.
- Cycle the suspension through full compression before finalizing mount placement.
- Verify clearance around tires, steering, axle components, shocks, and chassis tubing.
- The bump stop should engage before the primary shock reaches full compression.
- Custom fabrication is required.
Tech Insight
How does a hydraulic bump stop work?
A hydraulic bump stop acts as a compact secondary shock absorber during the final portion of suspension compression. Instead of allowing the suspension to hit a hard mechanical stop, it progressively slows movement and absorbs impact energy.
Why choose a 2.5" bump stop?
The larger 2.5" body provides increased fluid volume and thermal capacity for heavier vehicles and higher-impact applications. The 1-5/8" shaft also provides substantial strength for severe-duty suspension loads.
What does velocity-sensitive damping mean?
Velocity-sensitive valving increases damping force as shaft speed increases. A slow suspension compression receives controlled resistance, while a fast, hard impact produces significantly more damping force to reduce bottoming loads.
How do I choose between 2", 3", and 4" travel?
Travel selection depends on available mounting space, suspension speed, vehicle weight, and how progressively the suspension needs to be slowed. Shorter bump stops package more easily, while longer travel options can provide a more gradual engagement when properly positioned.
When should the bump stop engage?
The bump stop should engage during the final portion of compression and before the primary shock, coilover, or suspension component reaches its mechanical limit. Correct engagement height is critical to protecting the suspension without unnecessarily limiting usable travel.
Can this bump stop be rebuilt and tuned?
Yes. Radflo hydraulic bump stops are rebuildable, serviceable, and tunable. Valving can be adjusted to match vehicle weight, suspension geometry, driving style, and terrain.
