Fat tire

[darwin]

Good point about the chain, rear rim brake is an issue too if so equipped.

 

[KCvale]

On a serious note You might have trouble clearing your tire with the chain unless you have a shift kit. My 2.5" tire clears my stock chain setup by a mm or so.

I agree, you get over ~2.75"+ wide tires and you have chain aliment problems getting the chain around the tire.

Jackshaft the power to the right hand side and problem solved, the pedal system is already set up to clear the tire.

As a bonus you can use the bikes gears with the engine ;-}