Specialized Riprock Coaster 20 - 2025Traction, control, confidence, and funthe Riprock 20 Coaster is the perfect bike for your kid to start hitting the trails with. And with the simple coaster brake design, safety and fun aren't mutually exclusive anymore. While there are many notable features that make the Riprock awesome, it's the 2. 3 inch tires that provide a high degree of, well, shred abilitydelivering exceptional traction, control, and confidence for riding rough, off road