Check with sheldonbrown.com for a good explanation. Essentially there is a Schwinnn 26x1 3/8 " tire and there are everybody elses' 26x1 3/8 " tire and they are not the same. The Schwinn equals a 26x1 1/4 " of everybody elses. You probably would be able to relace with regular 26x1 3/8" rims.