. GP Suspension, 20mm Cartridge Kit for HD 39MM Forks – Bulletproof Cycles
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GP Suspension, 20mm Cartridge Kit for HD 39MM Forks

  • $1,199.00

After years of development, we are very excited to finally release our new 20mm cartridge kit to you.

We've spent many hours engineering and testing this new product to ensure that it is consistent with the premium standard we've set for ourselves. Uniform with every single one of our products, this kit was developed and manufactured here in Ventura County. We're proud to be USA made, but more important to us is having complete control of quality and componentry. It's something we never want to compromise on.

Our new 20mm cartridge kit is modeled off our 25mm cartridge kit, developed solely to fit a smaller diameter tube. We wanted to give the class of riders with smaller forks the best internal replacement system that money could buy. We didn't spare any cost on this kit. The idea wasn't a budget option like many of our competitors offer, but a high performing hydraulic system that performs as flawlessly as our 25mm cartridge kit initially developed on the racetrack where the limits of suspension systems are truly put the test.

Just like our 25mm cartridge kits, every cartridge kit is built for the rider after it is ordered. We know that just as important as having a good hydraulic system is the importance of having it setup for its rider. We pride ourselves in our custom-built kits that cater to the rider, and we are passionate about giving them that feel that lights their faces up and makes their hearts skip a beat. We also know that the guy who appreciates a forgiving ride across the country where the terrain changes daily needs a different setup than the guy who does wheelies or likes to rail canyons at mach 10.


Our 20mm cartridge kit, just like our 25mm kit is fully adjustable. There are 30 available clicks of compression, 30 clicks of rebound, and 12 turns of preload. Some people like to set their suspension and leave it, and some people like to tinker. Regardless, we guarantee we can find a setup for you.

We sell our kits in two lengths 32" and 34" - You will need to measure from the center of your axle to the top of your chrome tube(where your chrome tube meets your fork cap). Be sure to unload your front end when you take this measurement. The length you choose will determine your final fork length after you have installed the kit.


See installation video:



Pricing includes a spring set selected by our setup technician based on your riding information

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