Marin Alcatraz JR 24" Bike The Full Send, Scaled Down Pump tracks, dirt jump lines, and bike parks don't care how old you are, and neither does this bike. The Alcatraz JR gives smaller riders the same proven dirt jump geometry and construction as the full-size Alcatraz, scaled specifically for 24" wheels without cutting corners on the things that matter. The Series 3 6061 aluminum frame uses short chainstays to make manuals and wheelies feel natural and accessible, and the low, short overall profile keeps the bike responsive underfoot. A suspension-corrected chromoly rigid fork is designed to pump through lips and rollers without flex or wander. A Tektro hydraulic rear disc braking gives young riders confident stopping power they can actually modulate, which matters more than anything else on a bike where progression is the point. The drivetrain is a single-speed, which is the standard spec on most dirt jumpers. No shifting to think about means full focus on the riding, and the horizontal dropout design lets riders dial in chain tension without headaches. Vee Tire rubber keeps things rolling fast between hits. The Marin parts spec throughout is built to take a beating and stay in action, so the bike spends more time on the dirt and less time in the repair stand. For a young rider who is ready to start building real skills at the pump track or dirt jump line, this is the right machine to grow on. Features Series 3 6061 aluminum frame sized for 24" wheels with the same proven dirt jump construction as the full-size Alcatraz Short chainstays and low, compact geometry make manuals, wheelies, and pump track rhythm feel natural and accessible for developing riders Suspension-corrected chromoly rigid fork designed to pump lips and roll through jumps without flex, keeping steering consistent through the air and on landing Tektro hydraulic rear disc brake delivers modulation and stopping power sized for younger riders building speed and confidence Single-speed drivetrain with 135x10mm horizontal dropouts keeps the cockpit simple and lets riders focus entirely on technique Vee Tire rubber fast-rolling for pump track efficiency and dirt jump approaches Specifications Frame Series 3 6061 Aluminum, 24" Wheels, 135x10mm Horizontal Dropouts, 73mm Threaded BB, ISCG05 Tabs Fork Marin Series 2 Cro-Mo 24", Suspension Corrected, 100x9mm Dropouts Rear Shock N/A (Hardtail)Headset FSA No. 57E, Semi-Sealed Cartridge Bearings, 1-1/8" x 1-1/2"Shifters N/A (Single-Speed)Front Derailleur N/A (Single-Speed)Rear Derailleur N/A (Single-Speed)Crankset Marin Forged Alloy, 32T DM Chainring, 152mm Crank Length Bottom Bracket External Sealed Cartridge Bearings Chain KMC HL-1Cassette N/A (Single-Speed, 14T Cog)Brakes Rear Only - Tektro HD-M280, Hydraulic Disc, 160mm Rotor. No front brake. Wheelset Marin Custom Extrusion Rim, 27mm Inner, Pinned Joint; Rear Hub: Forged Alloy, 135x10mm, Bolt-On, Quad Sealed Bearings, Disc, 32H; Front Hub: Forged Alloy, Bolt-On 3/8" Axle, 100mm Spacing; 14g Black Stainless Spokes Tires Vee Tire Rail, 24x2. 25", LSG Compound, Wire Bead Handlebar Marin Riser, 6061 Double Butted Aluminum, 31. 8mm Clamp, 30mm Rise, 700mm Width, 4deg Up, 9deg Back Stem Marin 3D Forged Alloy, 31. 8mm Clamp, 35mm Extension Grips/Bar Tape Marin MTN, Closed End Seatpost Marin Alloy, 30. 9mm Saddle Marin DJ Saddle Pedals Alloy Platform Extras Marin Chain Tension Device Intended Use Dirt Jump | Marin Bikes | Alcatraz Jr 24" Bike Red Pink Fade | Rubber