treadless

Treadless is an adjective meaning lacking a tread or grooves on its surface, or, less commonly, a noun used to describe objects without treads. The term is most often encountered in discussions of tires, footwear, and engineered surfaces where traction is a consideration.

In tires, treadless usually refers to slick tires, which have a smooth surface with no tread grooves. They maximize the contact area with the road and are common in professional racing. Slick tires perform poorly in rain or on uneven surfaces. Most road vehicles require some minimum tread depth for safety, and driving on a treadless tire may be illegal on public roads.

In footwear, treadless or smooth-soled shoes have little or no tread. They are common in dress shoes and formal wear, offering a clean appearance but reduced traction on wet floors, ramps, or stairs. Some workplaces require slip-resistant soles, and many manufacturers add minor texturing to improve grip without forming deep treads.

Other contexts describe surfaces or feet designed without tread for specific traction characteristics, but the term is rarely used outside tires and shoes.