Originally Posted by
Iride01
As you increase tire size, tires grow in diameter about as much as they do in width. So check the tread clearance to the fork crown, seat tube and brake calipers or any other part of the frame the tread is close too.
Old stock rim probably won't be an issue with any size tire you can fit on that bike.
I got burnt by this on a Japanese sport touring bike. Had to file down the bottom of the head tube to fit a frickin 25mm tire.