On gravel and packed dirt tire width plays a more important role than tread and I drive them off-road almost every day. Muddy conditions are another story, and they slide on wet rocks too. But sand, crushed limestone or gravel wet or dry aren't a problem. I have bikes with 700 x 50 and 700 x 40 SMS's and have had ot issues with flats for almost three years now.
If I have a complaint about these tires its just that the reflective sidewalls need cleaning often - probably my fault for insisting on driving in the rain.
Last edited by Burton; 12-18-12 at 11:18 AM.