175T takes a 1/8 Axle (3mm). Du-Bro's low bounce captive air wheels have flown on more airplanes over the years than any other wheels on the market! The wall thickness is consistent throughout the wheel giving you a balanced tire. Comes complete with a sporty nylon metallic hub. Works well on grass & paved runways. Key Features: sporty nylon metallic hub 2 per package