Lesson learned for me to carry a pump next time! I did find a puncture mark as bike loaded on wrecker, but nothing stuck in tire. Didnt try to get it up on ctr stand as i was on packed sand on side of road. Called bmw roadside assist and 2.5 hrs later a wrecker showed up and towed the bike back 175 miles to dealer. No closer bmw dealer, i was in pretty rural location. Dealers closed Sun-Mon as well. Had a tire patch kit with me but with no experience using it, in a lousy location, and at start of long trip through middle of nowhere, with bmw roadside assist, I thought best to bag the trip, have dealer check the tire, and try again next year.
First flat in 20 yrs of riding, interesting to say the least.