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1.75 tire on Schwinn S2 hoop

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Well, those are confusing but I guess they have to be the larger S7 (not S2) diameter because they say so. Maybe they are from the era when Schwinn was still calling S7 1.75.
 
The first Schwinn middleweights had S-7's and the tires were marked 1.75 and Schwinn even stated them as 1.75. The tire name was Tornado.
Schwinn sold 1.75 tires that were branded Spitfire. Made to service the non-Schwinn bikes.


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GT, this has to be the most stupid thing Schwinn Bicycle Company ever did. It was published the same confusing way in the 1956 year. Thanks for "stating the facts" correctly about the Tornado 1.75/S7 tire size, no matter how bad it looks.

This had to be the point when we were given the 1 3/4" S7 sizing that would forever be confusing to bicycle riders.

John
 
GT, this has to be the most stupid thing Schwinn Bicycle Company ever did. It was published the same confusing way in the 1956 year. Thanks for "stating the facts" correctly about the Tornado 1.75/S7 tire size, no matter how bad it looks.

This had to be the point when we were given the 1 3/4" S7 sizing that would forever be confusing to bicycle riders.

John
There was a reason Schwinn made the S-7 a different diameter. The middleweight tires were not only narrower, the profile of the tire was smaller. So to counter that trying to keep the overall circumference the same as a 2.125 tire and at 26 inches, they made the rim larger keeping the overall circumference the same. For the car tire a 70 series tire fits the same size rim as a 40 series tire but the overall diameter is smaller. All the other bike brands had 25.5 tires, not 26” tires. I’ve heard that an S7 rim and Schwinn tire marked 26 x 2 x 1 3/4 is too big to fit some middleweight Murray’s or huffys.
 
There was a reason Schwinn made the S-7 a different diameter. The middleweight tires were not only narrower, the profile of the tire was smaller. So to counter that trying to keep the overall circumference the same as a 2.125 tire and at 26 inches, they made the rim larger keeping the overall circumference the same. For the car tire a 70 series tire fits the same size rim as a 40 series tire but the overall diameter is smaller. All the other bike brands had 25.5 tires, not 26” tires. I’ve heard that an S7 rim and Schwinn tire marked 26 x 2 x 1 3/4 is too big to fit some middleweight Murray’s or huffys.
I appreciate the explanation, but I believe the larger tire bead diameter on the S7 was the result of Schwinn adopting the tubular rim cross section. The bead rides up, "on top of" the tubular section, and they called it a straight side rim. The English 26 by 1 1/4 EA1 and 1 3/8 EA3 tires are even taller tires yet they are still called a 26" tire size. One thing is for certain, 70-75 years after the fact it is still a confusing subject.

The car tire might not be a good analogy. The 70 series is a percentage of the tire profile height to width, as in it's 70% as high as it is wide. The 40 series is only 40% as high as it is wide so it's a lower tire due to the lower percentage profile.

Thanks again for your original 1.75/S7 Tornado Tire posting and documenting it up with Schwinn documentation.

John
 
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