Here's a Great Frame and Fork Set so you can Build your Own Fat Bike!

This is a Motobecane Boris FS frame and fork. It's designed for use with 26 inch wheels and disc brakes. The frame is made of 6061 Aluminum Alloy, has a Tapered Head Tube, replaceable rear derailleur hanger, Water Bottle bosses, Rear Rack Seatstay Brazeons, and made for 170mm Rear spacing with standard quick release axle/ skewer. The Rock Shox Bluto fork has 150mm spacing and a 15mm Thru Axle.

This frame set comes with the fork, seat post clamp, headset and replaceable rear derraileur hanger.

FAT BIKES! Ingeniously simple concept. Giant tires = more control in loose conditions.
Super wide tires “float” over snow and sand…the fastest bikes you’ll ever ride on mud, bogs, deep sand and snow. As a bonus, they’re great conversation makers and super smile-generators.

How do Fat Bikes ride?
Way better than standard mountain bikes in snow? Yes. No Doubt. You'll ride over absolutely almost everything. Float over three feet of soft powder snow or deep sugar sand and laugh! You'll do a tons more riding – and way less walking.

Awesome in rough conditions such as snow, deflate the tires to provide more traction. Compare Fat Bikes to the difference between a car and monster truck SUV. Your fat bike can go more places, like sport utility vehicles.

The hottest trend in the mountain biking world right now. Fat bikes are hard to miss. Their giant, "fat" tires roll over virtually anything, which makes them an ideal winter mode of transportation because they help cyclists traverse snowy and icy trails with ease and traction. While the bikes were pioneered for snowy climates, such as found on the Front Range, they work well in a variety of environments including sand and loose rock, which has some local bike experts dubbing fat bikes as the all-around mountain bike of the future.
The same frame as on the complete bike at bikesdirect