The Mongoose Legion L100 is the flagship of the Legion series, designed for riders who have outgrown entry-level setups and are ready for a fully park, street, and dirt-worthy machine. Clad in a vibrant, eye-catching green, the L100 is a significant step up in durability and performance. Unlike its younger siblings, this bike features a 21-inch top tube and a full 4130 Chromoly construction—the same material used in professional-level BMX frames—offering the perfect balance of lightweight flickability and the strength needed to withstand massive landings.
Every component on the L100 is chosen for its ability to take a beating. From the 2-piece tubular chromoly cranks to the double-wall aluminum rims, this bike is built to be pushed to the limit on quarterpipes, rails, and dirt jumps.
Full 4130 Chromoly Frame: The entire frame, fork, and handlebars are made from premium 4130 Chromoly, providing superior strength and vibration damping compared to hi-ten steel.
Pro-Level Drivetrain: Features 175mm 2-piece tubular chromoly hollow spindle cranks with a 25T aluminum chainring and a mid-sealed bearing bottom bracket for maximum power transfer.
Double-Wall Rims: Equipped with Xposure Infinity-XD double-wall aluminum rims to provide the extra structural integrity required for high-impact landings and technical tricks.
Wide-Profile Tires: 20” x 2.4” high-volume tires offer a massive contact patch for superior grip and added cushion when coming down from height.
Precision Steering: A threadless sealed integrated headset and 50mm top-load stem provide stiff, responsive handling for precise lines.
Versatile Braking: Includes a removable brake mount system and an alloy U-brake, allowing riders to run a brakeless setup or maintain reliable stopping power.
| Feature | Specification |
| Frame | Full 4130 Chromoly, Integrated Headset, Mid BB |
| Top Tube Length | 21.0 inches |
| Fork | 4130 Chromoly |
| Crank | 2-piece Tubular Chromoly, 175mm, 25T |
| Rear Cog | 9T Sealed Bearing Cassette |
| Rims | Aluminum Double Wall, 36H |
| Tires | 20” x 2.4” |
| Handlebars | 4130 Chromoly, 8.75” Rise, 29” Wide |
| Weight | ~11.8 kg |
Intermediate to Advanced Riders: If you are over 5'8" and need a full-sized 21-inch frame that can handle advanced aerials and technical street riding.
The "Lifetime" BMX Buyer: Perfect for those who want a bike that won't need immediate upgrades; the full Chromoly build is designed to last for years of progression.
Style-Focused Shredders: Ideal for riders who want a bike that stands out in the park with its bold green finish and professional, clean lines.
Smaller/Younger Riders: The 21-inch top tube is designed for taller teens and adults; younger riders (under 5'6") may find the Legion L80 or L60 easier to handle.
Casual Sidewalk Use: If the bike is only for light commuting or neighborhood cruising, the high-spec L100 might be more machine than you need—the Legion L20 is a great alternative for casual riding.
The Legion L100 is a "pro-spec" bike at an incredible price point. Because it uses a Pivotal saddle and post, you get a much stronger seat connection that is also lighter than traditional "railed" seats. When you're setting this up, pay close attention to the chain tension; the 25/9 gearing is tight and responsive, so a well-adjusted chain makes a huge difference in how "quiet" the bike feels during drops. If you’re planning on hitting the local skatepark, come see us about adding some grind pegs—this frame is more than ready for them!
