Just remember that when you see 700C that it is 622mm.
Because of all the different bicycle tires with seemingly baffling illogical size markings that sometimes were beyond confusing, that in the late seventies an International Standard of the wheel's Bead Seat Diameter (in millimeters) WOULD APPEAR ON EVERY BICYCLE TIRE MANUFACTURED, FORWARD, FROM THAT POINT IN TIME, IN ORDER FOR PEOPLE TO BE ABLE TO DETERMINE EXACTLY WHETHER A PARTICULAR TIRE WOULD FIT THE BICYCLE's WHEEL.
Those of you with the ancient coaster brake beach cruiser bikes in either balloon or middleweight configuration with 26 inch wheels, HAVE SEEN 559mm APPEAR ON THE SIDEWALL MARKINGS OF ALL TIRES MANUFACTURED SINCE THE VERY LATE SEVENTIES, or 1980.
The early mountain bikes adopted this size in the Seventies and it (559) remained the mountain bike standard for the 1980's.
So 559mm never became obsolete, or rare, while others did.
Heck it was already frustrating, for the average person trying to find new replacement bicycle tires for their family's bikes back in 1972. There was no Bead Seat Diameter, international standard then! You, maybe, probably had the only useful information in the SEARS catalog, where they specifically stated DOES NOT FIT SCHWINN --or-- This Tire Fits Schwinn's Only , in their descriptive chart of tires pictured in the catalog. You could imagine the mom or dad who was trying to buy new tires for the hand me down bikes for the sixth child.
I don't have a clue as to why the tire markings had original designated markings that were ridiculously illogical and nonsensical, other than thinking that maybe they needed a classification name(NUMBER) that had not already been in use by another different size.
ANYWAY the international standard that has been in place since the late seventies where you see the BEAD SEAT DIAMETER in millimeters, preceeded by the expected mounted tire tread width in millimeters.
A Few Random Examples:
47 - 559 (26" mountain bike & ancient coaster brake/beach cruisers)
37 -590 (NON SCHWINN 26 x 1 3/8, also known as 650a , also known as EA3 )
37 - 597 (Schwinn 26 x 1 3/8, also known as EA1, also known as 650 ...note that this designation is 650 without letter suffix)
32- 630 (this is 27 x 1 1/4.....................once the dominant road bike wheel size, until 700C took over by 1985 or so)
35 -622 (this is 700C tire probably on a hybrid)
THE 700C (622mm) wheel replaced the 27" wheel (630mm) on upscale road bikes beginning in the late Seventies.
By 1986, there weren't any upscale road bikes that featured 27" (630mm) wheels.
The 700C wheel isn't any better or worse than the 27" wheel, it was simply mostly a trend towards the 700C to distinguish the new from the old.
There are several different bicycle tire sizes called
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The 650B (584 mm ISO) tire size is enjoying a revival. It offers wider an more comfortable tires than the popular 700C (622 mm) size, and also makes it possible to install fneders on bicycles which have too little clearnace with the larger size.
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Several different systems of size markings for bicycle tires are in existence. The modern ISO system is not as familiar as it should be, this article explains it.
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