Lets clarify a few things:
REYNOLDS 531 is TOTALLY WRONG in saying that the Schwinn Suburban is Varsity like!
SURFER ROSA is TOTALLY WRONG in saying that the Schwinn Suburban is a Low Level bike!
albrt is WRONG in saying that some electroforged Schwinns were 26 inch (590 iso)..... He, albrt DID NOT REALIZE OR JUST FORGOT that ALL ELECTROFORGED "lightweight" 26 INCH SCHWINNS ARE 597 iso and they are NOT THE SAME AS THE common everybody else 590.......
So Do Remember that Electroforged SCHWINN lightweight models with 26 INCH WHEELS are all 597mm.
26 x 1 3/8 (37-597) is the tire size SPECIFIC TO THESE ancient Electroforged Schwinns of the 1950's/1960's/1970's/Thru the 1982 Chicago END
The "Common Everybody Else in The world 26 x 1 3/8 tire (37-590) DOES NOT FIT ANY OF THE ELECTROFORGED SCHWINNS with Original Equipment Wheels!!
There is a GIANT made lugged frame with 3 piece crank that was marketed as the 1983 onward Collegiate, it has the Common 590 everybody else 26x 1 3/8 (37-590) because it is simply a GIANT Bicycle with Schwinn badging and decals!
As JEFF WILLS so correctly stated, the Schwinn Suburban was decidedly UPMARKET of the VARSITY .
The SUBURBAN 5 SPEED ALSO FEATURED FAR SUPERIOR EQUIPMENT (the Shimano built Model J 14-32 freewheel & the Shimano built GT-100 (1970-1973) & the Shimano built GT-120 (1974-1977) REAR DERAILLEURS which were both significantly better than the Huret Allvit on the Continental/Varsity/10speed Suburban.
As Jeff Wills also said, THE SUBURBAN has the TUBULAR FRONT FORK, it has the TUBULAR FRONT FORK (same one as Continental has), it has that TUBULAR FRONT FORK ON ALL THE CORRESPONDING SUBURBAN MODELS* (1970-1971 3 speed models........1970- onward 5 speed and 10 speed models)
Now there are a few days in 1974 where the assembly line was out of tubular forks so ordinary blade forks went on a few