Didn't make it halfway through the klunker pics without wanting to build one.
Here is one built from a free frame, (might be a Schwinn ) and recycled bike parts.
Had the wheels and tires left over from painting and tuning up the old Stumpjumper.
Took about most of one day, this one.
Finally slowed the kid down enough to change the bent fork on the orbo bike. Now 80s huffy so it’s atleast tube. He didn’t even want to take the time to paint it so red it is he wants to ride it on a 30 mile trail ride coming up.