Schwinn Runabout questions

[Spokeshave]

Does anybody know what frames were used for these bikes? Were they Pixie frames or maybe Sting Ray juniors? Is there a way to tell the difference?
What size tires were on Runabouts .
Thanks,
Spokes

 

[Robertk]

They were thier own frames. Note they are a bit longer than other 16" frames to accomodate adult riders and there is a rear brake bridge. Here are a few pics of my custom 10 speed Runabout. I was able, however, to use Pixie fenders ('74) on this bike.
Good luck!