Mongoose 24" Flatrock Mountain Bike Explore rad new trails with the Flatrock mountain bike by Mongoose. The Flatrock comes equipped with a lightweight aluminum hardtail frame and Element suspension fork that are ready to tear down the trail. 21-speed twist shifters and rear derailleur provide effortless gear changes, while alloy v-brakes deliver reliable stopping power. Plus, double-wall alloy rims offer lightweight durability. Get out there and explore with the Mongoose Flatrock.