Two circles Paradox

[Valeriy]

This should be explained...
https://www.youtube.com/watch?v=mW-0bZwoGwQ

[Matt Watts]

This should be explained...
https://www.youtube.com/watch?v=mW-0bZwoGwQ

And the answer is?

Not hardly.  But the circumference of the outside wheel surely equals the circumference of the outside wheel.

I've said it before, the whole point of these Visual Education folks are to lead you down a rat hole.

[BEP]

The only circumference that matters is that of the rotating disk.

If the drawn circles were instead surfaces to contact the lines they would both drag against the line. As the radius decreases the drag would increase because their circumferences are less the the linear travel against the line.

Why is this considered a paradox?