Schwinn s-5 20" wheel questions....

[asbug]

OK, I read a lot and cannot find an answer anywhere. I appreciate your help in my ignorance.
I have a set of S-5 marked wheels that appear to be 20" wheels.
They didn't come with any tires, but have the S5 hump in the middle of the wheel and are marked as S5's - should be ISO451.
I need to order some tires, but I have an issue... All the info I can find online state that the S5 in 20" should measure 17.75" in OD, but mine have an 18" OD...
I have measured with a large set of calipers to verify (no axle interference).
All the charts I can find state that this is a 22" rim ISO457.
I have read and read and cannot find a Schwinn made 22" S5 wheel; Just 20, 24. and 26 inch variants.
I can get some photos, but there is nothing special about these wheels other than I am building a single speed '68 Apple crate frame project and would like to use them instead of the usual S-7's that I have laying around.
I appreciate any and all help before I order the wrong tires (tyres).
Thanks, KC in North GA - barren wasteland for any thing Schwinn related...

 

[bloo]

The 451mm or 17.75" should be at the bead seat. Is that where you are measuring?

 

[Legislator]

The only 22" wheels I've ever seen on a schwinn came on the Enduro and Ms. Enduro. I think bloo is right on this one, but mounting up a 451 tire (or beaking your knuckles trying if it's actually a 457) would be an easy way to test.

Most of those Enduro/Ms. Enduros I've seen had basic box section steel rims with no knurling reminiscent of S series rims.

Sent from my SM-G970U using Tapatalk

 

[GTs58]

Schwinn didn't make a tubular rim for a 22" tire. That's a rare French bird and also used on some BMX bikes.

ISO for the 20" is 37-451
ISO for the 24" is 37-547

 

[asbug]

Awesome, Thanks everyone.
I was measuring the OD of the rim itself.
Thanks.

 

[rickpaulos]

I have a pair of Schwinn Enduro & Mrs Enduro with the 22" wheels. Red & Pink.
When you measure the outer diameter of just a rim, subtract about 12mm to get the iso/bsd number.

22 was only in Spain for a while but now it is used in bmx racing in the USA so there are some nice tires available for that size.