Originally Posted by
hokiefyd
Sure! The bike frame itself doesn't really care how wide the tires are (other than clearance, obviously). Tire diameter changes will impact the frame's geometry somewhat, but those differences would be pretty minor. I've done swaps like this before -- like putting 47-584 tires on my Giant Roam which came with 38-622 tires...and it rode great. In fact, I liked it better in that configuration. But I do a lot of mixed surface riding where I prefer the larger air volume in the tires vs. a high pressure narrow tire on larger wheels. It'll depend on what you want -- but the FX will ride fine just the same.
In my experience, you can deviate somewhat from stock tire diameters as long as there is no more than a 10mm difference front vs. Rear. Seems like trail is more negatively impacted when opting for a smaller diameter tire rather than vice versa.
I would definetely prefer thicker tires for my riding, but don't want to go much larger than the current tire diameter, especially since I would have to give up my rear fender.