Mongoose Massif Boy's 20" Fat Tire Bike Mongoose Supersized beach cruiser 4 1/4" knobby tires to 4 1/4" tires. Cruiser design frame with plenty of clearance to conquer any terrain Alloy 4" wide wheel set with disc brakes 7 speed gearing with Shimano rear derailleur 3 piece cranks and beach cruiser pedals