Ha Ha. I don't know the answer to that question. I do know that after I mounted those tubes with the Schwalbe's my son felt the tire and remarked that it felt pretty hard. I laughed and said just wait until I put some air in it.

Anyway, I rode about 35 miles on the tires today and the overall ride "feel" wasn't much different than the Vittoria's I had been running. However, the extra weight got noticeable after mile 15. So I'm going to gird my loins and take them off this afternoon.