While not quite a clydsdale, I am a bit on the heavy side, upgraded to a higher pressure, more rugged tire -
http://www.amazon.com/gp/product/B004JKCZOG. For those looking to do something similar, but on a tighter budget, I saw
Freedom Cruz Sport 20x1.5 City Tire today in the Nashbar bargain bin, might be of interest to some.