The first bike every kid should ride – The Opus Curve. The Curve comes in three sizes, 16″, 14″, and 12″. These little machines are built using our proven youth geometries with durable steel tubing. All of the bikes come equipped with a rear coaster brake and our signature Opus stem pad. The Curve 14 also comes with a rear V-brake with a short reach lever. When it comes to youth bikes, it’s all about the learning Curve.