Door number 3..

Thorn Resistant Inner tubes have a lot more Rubber in them, and its thicker on the Outside ,

Rode a Puncture Free 9 months on a Bike tour using a pair. 700c-40 p/v

+ they hold air Longer..

now I Have 26" in the winter Ice Bike (studded tires) , 20" in 1 bike trailer and the Bike Friday, and 12.5" in the other bike trailer. s/v