Originally Posted by
mdarnton
Maybe this will help? Depending on what your present tires have written on them.....
Thanks... Unfortunately there is no size indicated on the current tires. The link above indicates that a 26 x 1 3/8 Schwinn rim would be ISO 597 though the 70s... I was able to pin down the date of my bike to 1986 based on old Schwinn catalogs (that seems like the only year with a 3 speed Shimano rear hub, which this bike has). When I went to purchase ISO 597 tires the online shop had a note that they would not fit 1980s Schwinn bikes... Unfortunately the catalog I found for the 1986 Collegiate didn't specify exact wheel/tire size.
EDIT: I see that the tires cold also be ISO 590... I guess this is probably the best bet...