I have had two custom trucks since 2000 (96 S-10 with custom 3 link rear suspension and airbags, and a 94 S-10 Blazer with a stereo and air tank taking up all of the cargo area) with no spare tires with no problems. I don't even carry any fix-a-flat. I replace my tires probably a little sooner than needed to prevent any problems, but I really don't worry about it.