Diamondback Bicycles El OSO Grande Fat Mountain Bike Designed to excel in sand or snow, the high volume / low pressure tires gain purchase on surfaces that have long been unrideable.;6061-T6 aluminum frame/fork with hydroformed tubes, 1.5" tapered machined headtube, fits up to 26x5" tire DB El Oso Custom rigid fork with 15mm thru-axle SRAM X5 10speed rear derailleur and FSA double chainring crank give you 20 speeds to choose from Mechanical disc brakes help you stop well in varied conditions 26x 4.9" tires are wide enough to keep you going where other bikes give up Designed to excel in sand or snow, the high volume / low pressure tires gain purchase on surfaces that have long been unrideable.