Plastic Gears Are the Future (2017)

For an apples-to-apples comparison of a solid nylon spur gear, a nylon spur gear with a stainless-steel core, and a reinforced nylon spur gear with a carbon steel core, results in the following: (The following materials properties are taken from the PS (solid nylon), PU (stainless steel), and the NSU (carbon steel) series from KHK.) Setting the toque limit of the MC901 solid nylon gear at 100 Nm, the maximum allowable bending strength torque for an equivalent stainless-steel hub gear with a MC901 rim would also be 100 Nm. However, the equivalent carbon-steel core gear, with a 30% fiberglass fill nylon rim, will have a maximum allowable bending strength torque of 138 Nm.

Source: www.machinedesign.com