There was a story in The Province about 3 - 4 years ago where a Vancouver rider was on a trip on his ST1300 in Baja where he ran a bit short of tire tread. He ended up getting a ride in a pickup truck, along with his bike, from an American living in Mexico and was taken to San Diego where the tire was replaced. It was a newsworthy story because he lost a saddlebag in the process. The bag, it turned out, had been left in the guy's pickup and hidden under a blanket placed there to protect it. The pickup owner opened the saddlebag, found an audio book on learning Spanish borrowed from the Vancouver Public Library. He called the library who relayed the message to the bike owner that this guy in Mexico had his saddlebag. They got hooked up and the Vancouver guy got the bag shipped home. It was interesting because I knew this guy; we had ridden part way home together from Montana 5 year ago. He is a friend of another riding buddy.
So, after that long introduction, we rode together again recently for 3 days. When I stop behind other riders, I have a habit of looking for nails and worn tread. Just before we got back onto I-5 down at Burlington, I pulled him over and asked him to have a look at his rear tire.
I don't know for sure, but they look like Metzeler Z6 tires he's wearing. I had them once but never again because of the lack of wear bars near the center ( if anywhere at all ).