The toughest tires I've used have been low end Continentals in size 28 or size 32 with the black sidewalls. The roads of inner city Houston look like Berlin in May 1945, but a cheapo Continental, combined with Continental tubes, handles potholes, broken concrete, and random urban debris with ease.

I do NOT suggest using Continentals with the thin, light, brown/gold sidewalls. Under the summer sun, those sidewalls soon crack and split. The cheaper versions with the heavy black sidewalls are the TOUGH version. I also had sidewall problems with the Pasela's...the summer sun in Houston destroys thin sidewalls very rapidly.