1.
winter tire that grips snow and ice without metal studs
A winter tire that grips snow and icy roads through soft rubber and a special tread pattern rather than metal studs. Standard in snowy regions of Japan, where studded tires are largely banned for damaging road surfaces.
From English "studless tire." Often shortened to スタッドレス.
Cultural note
Metal-studded tires (スパイクタイヤ) were banned in Japan in the early 1990s because they ground road surfaces into harmful dust, so スタッドレスタイヤ became the standard winter tire.