flatless

Without a flat.

Adjective

  1. Without a flat.
  2. That will not deflate, without flatness.
    • In 1979, a California company began manufacturing a flatless polyurethane tire for wheelchairs. - 1991, Malcolm Abrams, Harriet Bernstein, More Future Stuff: Over 250 Inventions that Will Change Your Life by 2001:

Origin

From flat + -less.

Forms

more flatless most flatless