The influence of footwear tread groove parameters on available friction

• The available friction provided by a shoe outsole is influenced by many factors, including the design of tread grooves.
• We investigated the influence of three tread groove parameters (width, depth, and orientation) on available friction.
• Groove orientation had the greatest impact on available friction.

The purpose of this study was to determine how footwear tread groove parameters influence available friction (COF). Utilizing a whole shoe tester (SATRA STM 603), 3 groove parameters (width, depth and orientation) were evaluated. Groove orientation had 3 levels (parallel, oblique and perpendicular), width had 3 levels (3, 6 and 9 mm) and depth had 3 levels (2, 4 and 6 mm). In total, the COF of 27 shoes, each with a distinct groove combination, was assessed on wet porcelain tile. The 27 groove combinations produced a wide range of COF values (0.080–0.344). Groove orientation had the greatest impact on COF, explaining the greatest variance in observed COF values (ŋ2 = 0.81). The most slip resistant groove combination was an oblique orientation, with 3 mm width and 2 mm depth. The least slip resistant groove combination was a parallel orientation, with a 6 mm width and 6 mm depth.