Hey Kevin,
I'll let you know. I've run the Bridgestone BT39ss 2.50-18's for awhile now but they are prone to rear flats due to the tube chaffing on the ribbing inside the sidewalls. The Heidenau looks similar in profile but the tread is different and they are a bit taller than the BS tire. They do feel pretty soft and I've heard good reviews so far.