Why does 20" not = 20" ?????

[ChrisMac]

Schwinn Bantam. Original 20X1.75 rear tire removed.
Newer Huffy BMX. 20X2.0 tire removed.
Attempting to put the BMX tire on the early Schwinn rim. The newer 20" tire will not fit over the early 20" rim? Why??????

 

[deorman]

Check again. You probably have a 1 3/4" S-7 tire, which is NOT the same as 1.75".
http://www.isisconsulting.org/catalog/bike/p2010.htm

 

[DHrider]

there is no standard for tires... each brand has their own measurement for their tires... some measure from the center to the edge of the thread some measure from the center to the edge of the case. as well some of the wall heights are measured from the bottom of the bead to the top lug of the tire and some are measured from the top of the bead to the top of the case.

manufactures sizes vary. tires from the early years are the worst. most manufactures from the 2000s and newer are more similar.

 

[DHrider]

Check again. You probably have a 1 3/4" tire, which is NOT the same as 1.75".
http://www.isisconsulting.org/catalog/bike/p2010.htm

this is true as well.... perhaps i am over analyzing.

 

[mikesbikes36]

schwinn rims r bigger ....differnt system ...1.75 dosnt equal 1 3/4 ... u need a schwinn tire ...

 

[Wildcat]

Schwinn made their rims a tiny bit larger so you would have to buy their tires. Everyone else's 20" rim was standard and you could use any 20" tire, except for schwinn. These were the Schwinns made in America, before 1983.

 

[ChrisMac]

Well, that's just silly. Thanks Schwinn.

 

[outskirtscustoms]

Well, that's just silly. Thanks Schwinn.

Actually Schwinn was pretty ingenious in doing this, it ensured that people buy the tires that only they produce, use the products that only they produce, buy the accessories that they produce....They play a monopoly on the bike market. Kinda like Microsoft of the bike world. :roll:

 

[deorman]

Actually Schwinn introduced the basis of the modern standard decimal rims (ISO 406, 20", ISO 559 26")commonly used on cruiser/bmx/mtb to this day, originally called S-2. The 26" S-7 fractional middleweight (ISO 571, 26"x1 3/4") corresponds to British 650c rims size-wise, but the 20" S-7 (ISO 419) is completely unique to Schwinn. Other companys kept using the earlier size rim with smaller tires for their middleweights. Then there's the world of narrow fractional 26" wheels :roll: , but that's a dfferent can of worms.

 

[Blueboy5000]

Lots of stuff on early Schwinns is proprietary sizes. Tires being the most noteable, or should I say common size problem vs the rest of bike-dom. Other Schwinn only sizes of things that pose problems are cranksets and chains. In fact I have a Schwinn Varsity 10spd that has the entire "freewheeling" mechanism as the chainwheels. On this bike the the sprocket cluster is fixed to the rear 24" inch rim and the rotating wheel moves the chain at all times while the bike is moving. It also uses Schwinn sized tires and regular 24" ten speed tires do not fit at all.

It's a cool stand-alone design, unless you wanna grease up the (for lack of a better term) the free-chainwheel bottom bracket.

 

[ChrisMac]

So.....much.....information.....

I think I have a headache.

 

[schwinnmesa]

Schwinn was genius that way; people had to go back to the dealership.

Headache causer? Oh yes! Those Schwinn S-system tires don't come cheap either!

 

[X-RAY]

i understand the idea of forcing you to come back to the dealer, and im glad they had the freedom to do so. but, somethings ,in my opinion, should be standardized by law. for example, all car hood latches should be in the same place, no more looking like an idiot trying to open your hood. all gas tanks should fill from the same side of the vehicle, much less hastle at the pumps when everyone is facing the same direction(and if you drive different cars, im sure youve pulled in on the wrong side before ) .everyone should have to ride a bike in traffic before getting a license, maybe then we would get a little more respect and safety. and all bike parts should be standardized somewhat. saves us time money and frustration. ok, i feel better now, carry on!

 

[kngtmat]

I hate that the same way with all these new types of dang screws they use today, keep it phillips, flatheads, the same thing with nuts & bolts too.