'95 Trek 800 Sport: started with 1.95, 2.1 just barely fits with rubbing if mildly deflated. Happily running 1.75, now, and going 1.5 on the next go round. Currently riding smooth and steady
on Impact Streetpacs (Schwalbe)
FRANKENTREK
Being budget minded, thinner tires use less rubber and can cost less, ymmv....