mag wheel

noun Automotive.
  1. a wheel containing magnesium or aluminum generally alloyed with steel, which makes it lighter in weight and shinier than an ordinary steel wheel: used especially on racing cars and sports cars.

Origin of mag wheel

1965–70; mag, by shortening of magnesium
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018