GP Suspension Harley Bagger Cartridge Kit
End the Bagger Suspension Struggle
Tired of "hideous brake dive" that makes your bike "consistently bottom out on harsh bumps?" Fed up with forks that "always sucked" and leave you "wallowing over medium freeway bumps?" Stock bagger suspension frustrates riders with excessive front end dive during braking, harsh impacts that "knock your teeth together," and the feeling that your "front suspension can't hold you up."
GP Suspension eliminates these problems. Our precision-engineered kit delivers proper spring rates, enhanced damping control, and consistent performance - transforming your bike from wallowing and diving to confident and responsive.
Racetrack Innovation, Street Perfection
Our bagger cartridge kit brings proven racetrack technology to the road—engineered to absorb every bump while delivering exceptional confidence and traction. This isn't an overly stiff race system; it's precision-tuned for optimal street performance, blending race-proven innovation with road-ready comfort.
Manufactured & Built entirely in Ventura, CA. We've never outsourced our machining or engineering—every component is wholly American-made.
What Sets Us Apart
Revolutionary Three-Valve Technology
Our advanced three-valve system delivers superior fluid control and pressure management compared to conventional two-valve designs.
The advantage: The base valve, working alongside rebound and compression valves, provides precise hydraulic flow modulation. This eliminates fluid cavitation and pressure spikes that cause harsh, inconsistent damping in lesser systems.
Real-world performance: Soft response during low-speed compression for comfort, ramping up effectively for heavy impacts like potholes or speed bumps. Your suspension adapts intelligently, maintaining traction by keeping tires consistently connected to the road.
Integrated Topout Spring Control
Integrated Topout Spring Technology eliminates harsh fork extension at full travel while maintaining critical tire-to-ground contact. This prevents the jarring impact typically experienced when forks reach maximum extension and ensures your tire stays planted for maximum traction and control—essential for both safety and performance in all riding conditions.
Progressive Bottom-Out Control
Advanced Bump Stop Technology provides progressive bottom-out control that prevents harsh compression impacts. Rather than a sudden, jarring stop, our system progressively controls compression at the end of travel, maintaining traction and rider confidence even when suspension reaches its limits—critical for aggressive riding and unexpected road obstacles.
Custom-Built for You
Every kit is tailor-made considering your weight, bike weight, and riding preferences. Whether you want buttery smooth cruising on bumpy roads or rail-like precision for aggressive riding, we build your kit specifically for your needs.
Full Adjustability at Your Fingertips
Located conveniently on your new fork cap:
- 12 Turns of Preload Adjustment
- 30 Clicks of Compression Tuning
- 30 Clicks of Rebound Control
Set it and forget it, or fine-tune between rides—we're always a call away for setup support.
Performance & Length Options
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Increased stroke: 117mm to 122mm (optimized through extensive R&D)
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Two length options available:
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Stock length (recommended for use with GP Suspension 12.8"-13.1" shocks)
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2" over (recommended for use with GP Suspension 13.5"-14" shocks for more playful, responsive handling)
Note: Pipe modification or short-style pipe required for shock lengths exceeding 13.1"
Installation Notes
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Upper tube modification required: Larger piston diameter needs additional clearance and OEM bottoming assembly removal
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Optional: Add our pre-modified fork tubes to your order
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2024 ABS models (2" over): Extended lower lines required (we recommend Magnum 2" over lines for ABS dual disc models)
Experience more traction, more comfort, and most importantly—a ride that puts a smile on your face.
Pricing includes a spring set selected by our setup technician based on your riding information
We've taken our GP Suspension 25mm cartridge kit that has helped national level racers get to the top step of the podium and changed the valving system, spring rate, and optimal travel to turn your bagger into a dream. We know that good suspension starts with a quality hydraulic system capable of absorbing every irregularity of the pavement your riding on. We've spent decades working with riders to perfect this system. Our system differs from our competitors on various points. It features velocity optimized 25mm compression and rebound pistons that are custom shimmed to your weight and riding preferences. The bagger is a big bike, so we found putting an additional base valve in the bottom of the cartridge helps maintain traction when the front is loaded suddenly such as a big bump or a situation where you need to suddenly get on the brakes. Where our competitors two piston systems tend to "pack up" as the oil struggles to quickly push itself through the single compression piston our 3 piston system gives you a seamless feel through the stroke.
We've never outsourced any of our machine work or engineering. Everything in your front end is wholly American made in Ventura, CA, and we are proud of this. The end result? More traction, more comfort, and most importantly a ride that really puts a smile on your face. We take every rideru2019s weight, and their style of riding into account when we build their kit. We know that setup is key to good suspension, and we take pride into giving every rider a kit that is custom made for them. Whether you want a buttery smooth ride to cruise your bumpy home roads, or you want a ride on rails that can take the abuse of a track day. We have you covered.
Our kit is fully adjustable (preload, compression, and rebound). These adjustments can be found on your new fork cap. Some riders prefer to set it and leave it, while some riders like to tinker between setups. Either way, we are a call away for all your setup questions.
Our kit bumps your stroke from 117mm to 122mm. We work hard on the R&D side when it comes to finding the optimal amount of stroke for every bike.
We also build custom lengths to accommodate those who want more ground clearance, or different geometry. The customer will need to supply the longer chrome tubes in these cases, and we will build it to length. Feel free to give us a call with questions. Extra charges may apply**
Slight modification of your upper tubes required** the larger diameter piston requires more clearance and removal of the bottoming cone is required. See installation video below:
https://www.youtube.com/watch?v=Ffv6WN6m8Rg
Pricing includes a spring set selected by our setup technician based on your riding information
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