In my experience, tire width makes less diference than tire quality. For years I road my bike friday pocket rocket pro to work with 26mm primo comet kevlars. Even toured with them on packed dirt in chiapis. The tires were great, but the bike got stolen while locked in a bike rack (hence the reason to ride a beater). My beater is still a pretty good bike though, I fixed up my old terry classic touring bike, upgraded her to drop bars and an ultegra/XT mix. In the beginning I used panaracer pasela tires, 25mm wide, but not tourguard and flatted a lot, so switched out the rear only for the 32mm wide TG tire and have been fine. But, some days I have taken in my terry titanium Isis which has 23 mm shwalbe stelvios which also have a flat resistant compound built in, and have had no problems. I am now on cape cod, with sand and coastal roads, and have no problems with Isis and her skinny 23mm tires, but I do have pretty decent bike handling skills. In fact, I have yet to have a flat since I put the stelvios on her. They are really nice fast tires!