In my world it's very common to use smaller tubes as spares to save weight, especially in the MTB and fat tire world. For example, I carry a 26x2.5-3 inch tube as a spare for my 26x4.8 tires. Only had to use it once and it's still working. Kind of a pain overcoming the resistance when inflating a smaller tube to fill the large space. Huge weight/space/cost savings over the normal 4.8 inch tube.
Last edited by Dr.Lou; 05-26-19 at 07:59 PM.