Originally Posted by Davezilla
..makes a lot of power way down low like a trials engine... that could turn out to be a really fun machine for a small closed course or even as a trials style bicycle....
I don't think anyone has built anything like that before, but it would be interesting and fun....
This Surly was built specifically to be a trials bike, ~15MPH top speed but a frigg'n goat that can climb cliff's ;-}
It's jackshafted to bypass the disc and clear the rear wheel but just a fixed sprocket on the rear, no gears, he didn't want them.
But back to fat tire bikes...
Your frame has to accommodate them.
Sure you could make your own front fork, but the back would be an issue modifying a bike built for 2" tires.
Best bet is to buy a decent fat tire bike to start with and jackshaft it.
The Sun Crusher is a pretty decent Fat Tire bike, it has a big center cavity a 4-stroke would fit in, 7-speed gears and dual V brakes that fit the 3" wide rims, tires run 3.5" wide in the middle.
It makes for nice 7-speed shifter with power and very comfortable to ride.
Great on the pavement and very good on soft surfaces, you should just float right over the sand bars on the road.