After having replaced my side-brush model, and then having the brushes break, then replacing the brushes with a TPU brush and having it strip out... I decided to remodel the entire thing. This version allows for the TPU brush with a larger splined shaft to prevent strip out. It also includes a new replacement gear with the splined shaft. Last, it includes the cover with enlarged opening to accommodate the larger shaft. The replacement cover was necessary because mine shattered and the gear rides in a little shelf area with in the gearbox. The collar is used to offset the driving gear from the up conversion gear, so they don't rub. Make sure to use some grease to prevent friction and prevent parts from melting.

Brush - TPU print (95A) - Allowing thin walls will help print with the brush ends Gear - (Nylon preferred) ABS/PETG Cover - PLA/ABS/PETG

Thanks to Devise3D for the base gear model which you can find here: https://www.cgtrader.com/products/roomba-series-675-corner-sweeper-drive-gear Thanks to OhSnap for the base brush model: https://www.thingiverse.com/thing:2645821

Note: I did make the teeth on the gear have more length to accommodate FDM effects. Blender files included. Admittedly, the top of the cover doesn't look amazing, but I wanted the clean precision on the inside of the cover, so I printed it upside down.