>>1542146There might be a wear indicator on them somewhere on the tread area. Some feature that indicates you should replace the tire when it wears away. If it's the one in the pic it might be those two groves running lengthwise all around, but that's a guess. You could email trek customer service and ask.
1800 miles sounds low, but it depends on what kind you had I guess. It's still possible to get flats even with not-worn-out tires.
