Tire size

What is the largest, fattest tire size that fits on a Schwinn S7?  1-1 3/8?  1-1 3/4?  Or larger?

Usually it's the frame that's the limiting factor, not the rim... My rims aren't particularly wide and I've got 2.125's on them no problem.  As long as it's not roadie-rim narrow it'll take pretty much whatever you throw at it, provided the tire fits between the chainstays...

Just to follow up on this one nearly a year later, the only thing that fits on a Schwinn S7-sized rim is an S7-sized tire!  The actual rim diameter is different from "standard" 26" wheels.  Go figure!!