GP Suspension Cartridge Kit for 14-22 Bagger


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GP Suspension 25MM Cartridge Kit for 14-22 Bagger

GP Suspension Cartridges include a spring set, specifically selected by a master setup technician based on your individual riding information. Kits are built to order per your order specifications. Lead time is only about 4-5 weeks.

*Please leave your approx weight in the order notes at checkout. This is important information needed when building your specific kit.


  • bumps your stroke from 117mm to 122mm
  • customized spring set
  • velocity optimized 25mm compression and rebound pistons
  • fully adjustable (preload, compression, and rebound)
  • American Made

Available in custom lengths*. +2″ and +3.5″ overstock lengths will require longer fork tubes.


  • 14-15 FLHR/FLHX
  • 16-17 FLTR
  • 18-22 FLHT/FLTR

From GP Suspesnion:

“We’ve taken our 25mm cartridge kit, that has helped national level racers get to the top step of the podium, and changed the valving system & spring rate. We’ve also optimized 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. Our competitors two piston systems tend to “pack up” as the oil struggles to quickly push itself through the single compression piston. Our three 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 entirely American made in Ventura, CA and we are proud of this. The end result is more traction & more comfort. Most importantly, a ride that really puts a smile on your face. We take every riders 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.

Extra charges may apply** We also build custom lengths to accommodate those who want more ground clearance or different geometry. You will need longer fork tubes in these cases.

Slight modification of your upper tubes is required.** The larger diameter piston requires more clearance and removal of the OEM bottoming assembly is required. See installation video below:


How to adjust your GP Suspension 25mm Cartridge kit.

Adjustments can be broken down in the following way:

Preload: This is the spring adjustment for your kit, by turning the 14mm dial on your fork cap clockwise you are adding preload to the springs in your forks. This is going to result in a more supported ride. Preload is counted in full rotations. To set your preload you will back the 14mm all the way out(counterclockwise) and count rotations as you spin the 14mm nut in(clockwise).

Six turns of preload is a good place to baseline your suspension.

Your kit will have come with a travel indicator and you can use this to measure how much travel you are using. Keep in mind that the casting is not typically the bottom of your travel. Feel free to call us and we will let you know how far above the casting your model bottoms out at. Measuring how much travel you are using is a good way to fine tune your preload.

Compression & Rebound: These are the hydraulic adjustments for your bike. They will be the 3mm brass allen adjusters found in the middle of your preload adjusters and/or at the bottom of your fork leg. They control the hydraulic bleeds for the up and down damping on your bike. The compression adjustment will adjust the rate at which the fork is able to compress when the front is loaded. The rebound adjustment will adjust the rate at which the fork is able to extend back as the front end is unloaded.

The more you close the rebound and compression off by clicking the adjusters in (clockwise) the slower your fork will compress and rebound. The more you open the bleeds up by clicking the adjusters out (counterclockwise) The faster your bike will compress and rebound. Rebound and compression adjustments are counted in clicks. To set your rebound or compression click your adjusters fully closed (All the way clockwise), and then count clicks as you turn them out (counterclockwise).
14 clicks on your rebound and compression is a good place to baseline your suspension.


Additional information

Weight 10 lbs
Dimensions 25 × 4 × 4 in

Stock Length, +2" Overstock (for 24 7/8" tubes), +3.5" Overstock (for 25.5" tubes)

Riding Style

Casual Road Riding, Cross Country Touring, Aggressive Street Riding/Canyons, Track Days/Racing

Preload Adjuster Color

Blue, Red, Black


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