Just bought a 14' SB lookin to put bigger wheels 21" front and 18" rear.
can anybody tell me what's the biggest I can go without making major changes to my front folks? I read the biggest I can go on the 180 rear tire with a wide tire kit.
21"x3.5" front??
18"x5.5" rear??

 

For the rear a 18"x5.5" with a 180 width tire is the biggest you can go. You will need the fender supports from the Street Bob wide tire kit or the detachable hardware kit. This is so the tire will not rub on the sides. Also your shocks will need to be at their stiffest setting.

For the front you can get a 21"x3.0" rim and a 130 width tire. You might have to remove the front fender or modify it for more clearance though.