Tarmo 5 Front Axle Upgrade

I was having a lot of trouble with the front axles breaking—typically, the collar behind the bearing would snap. I’ve replaced this collar with a large-diameter M6 steel washer. Additionally, an M4x20 coupling nut (long nut) is inserted into the front axle. This setup is now quite durable. You will need: 1x large-diameter M6 washer, 1x M4x20 coupling nut, 1x M4x40 hex socket button-head screw, and 1x M4 brass threaded insert. The assembly process is clear from the photos; simply follow the sequence shown.

The Front Bearing Hub has also been modified: it has been widened by 5 mm to prevent the head of the axle assembly screw from rubbing against the original steering knuckle, and the recesses in the mounting tabs have been filled in. I also fine-tuned the bearing seats; there is much less play now, yet the bearings can still be easily pressed in by hand. I recommend calibrating the M4 screw holes using a 4 mm drill bit. Remember to mirror the Front Bearing Hub in your slicer to create the matching part. I designed the front axle as a two-piece assembly (incorporating that small insert); when I tried printing it as a single piece, the contact surface for the washer turned out extremely rough and stringy—this approach eliminates that issue.

Print Settings:

I printed everything using ASA, with 3 perimeters, 3 bottom layers, 3 top layers, and 100% infill. Speed: 50 for the first layer, 120 mm/s for the rest; I printed it slowly, and the print quality is much better.

Temperature: 269°C for the first 2 layers, 264°C for the rest.

Don't forget to place a washer between the bearings, as shown in the photos.

The wheel now spins freely without resistance, doesn't wobble from side to side, and is significantly more rigid. Enjoy! :-)