6 HOLES Hub Shaft Axle Adapter 16mm 5/8". #35 6 hole family sprockets and axle hub adapters. Please choose adapte size , sprocket size or combination. These sprocket wheels are designed to be used with #35 roller chain which is 3/8" pitch. These are commonly used in Go Karts. Chain wheel sprockets are made of steel and are nickel plated and the hub axle adapters are usually made of aluminium and are keyed but also come with a set screw to lock it to the shaft or axle. The hub adaptor is a little bigger than the shaft so it goes in smoothly but has a tight fit.