As we roll the tyre through one revolution, it will have traversed a distance of X, which is the same as its circumference. Obvious stuff so far.

Now look at the inner wheel. It has also traversed a distance of X while completing one revolution but that distance is much greater than its circumference.

Go Figure!

Image and intrigue courtesy of http://io9.com/the-wheel-paradox-that-stumped-aristotle-and-galileo-1507994415