The use of 3D printing to manufacture nylon polymer gears is evaluated in this paper. More specifically, Nylon spur gears were 3D printed using Nylon 618, Nylon 645, alloy 910 filaments, together with Onyx and Markforged nylon proprietary materials, with wear rate tests performed on a custom-built gear wear test rig. The results showed that Nylon 618 provided the best wear performance among the 5 different 3D printing materials tested. It is hypothesised that the different mechanical performance between nylon filaments was caused by differences in crystallinity and uniqueness of the Fused Deposition Modelling (FDM) process. SEM (Scanning Electron Microscopy) revealed dramatically different wear behaviour for the 3D printed gears when compared to literature reports of injection moulded gears. Monitoring with a thermal camera during wear tests was used to analyse the thermal performance of gears during wear tests and together with SEM was used to analyse gear failure mechanisms. The performance results showed that gears 3D printed using Nylon 618 actually performed better than injection moulded nylon 66 gears when low to medium torque was applied. Display omitted •Spur gears produced using 3D printing and a selection of nylon filaments to determine differences in wear behaviour.•Somewhat unexpectedly, 3D printed Nylon 618 gears performed better than injection moulded gears when torque applied below 12Nm.•The causes of different mechanical performance between nylon 3D printing filaments has been investigated.