Originally Posted by Fossil
Am I missing something here?
Isn't 1.75 the decimal equivalent of 1 3/4?
Yes they are the same probably everywhere except when it comes to measuring tires. Schwinn back in the day were trying to make it so that you had to buy replacement tires and tubes only from an approved Schwinn Dealer rather than the local Department Store or Auto Supply. Hence Schwinns Middle weight tire was a 1 3/4 and only fit their S-7 rim, where everyone elses was 1.75 and would fit the standard 26 in. rim. Schwinn also did the same thing with their 26 X 1 3/8 in. and 24 X 1 3/8 light weight tires. Schwinns were made to fit their 26in. S-6 rims and 24in S-5 rims where the other manufacturers used tires that fit 26 X1 3/8 EA-3 rims. Here is a link to the Sheldon Brown article on tire sizes. Tire Sizing Systems