Diamondback Bicycles El OSO De Acero Fat Mountain Bike El Oso butted heat-treated steel frame, 1 1/8" headtube, 150mm rear end, fits up to 26x5" tire Diamondback El Oso Custom rigid steel fork, 135mm QR dropouts Shimano 3x9 drivetrain gives you 27 speeds to choose from Shimano Alivio mechanical disc brakes DB 75mm wide rims hold the trail crushing 26x4.0" fat tires