How's it going, guys? I was recently gifted an 1999 cannondale m500 frame that was used by my local police force (yes, I'm in love with it because it's bright blue and 'police' is emblazoned onto the frame). I'll run it as a SS daily commuter for the time being. Aside from cantilever brakes, the frame is bare. It is fit for 26" rims. I just bought a Weinmann wheelset from my LBS, though I don't know the widths of said wheelset. All I know is they cost me 120$, are black, listed as MTB rims, double walled, and are listed under parts #JB66876 . I'm unsure whether that parts number is specific to my LBS or not. All i know is that a general google search returns nothing, and I'm in one Unibroue too deep to get into some serious researching.
The question in my header is slightly misleading as I prefer slimmer tires. My question, without knowing the exact diameter of the rims, is could I potentially be wasting money buying 1.5" tires from the internet (the tires at my LBS are overprived) on the off chance that my rims can't support that slim of a tire? Is there much of a difference between 1.75 and 1.5? And finally, is there any (reltively cheap) tires that you all as a community recommend?
I know this question could be answered very quickly during business hours by my LBS, but I typically do appreciate the responses given on bikeforums- and I'd like to know some background details before I call them in the morning.