Ever since I rode my first scooter in the rain, I've hated the rear fender/brake. No matter the scooter, none of them had a fender that reliably protected me from wetness and dirt. I should mention that I ride my scooter in all seasons and weather conditions; rain or shine, it always gets me to my destination quickly and safely in the city, but I also often end up wet and dirty. This is about to change with a 3D-printed fender/brake.

The Story

The Idea

The First Attempt

2024: The Second Attempt

Since I've worked with so-called "living hinges" in my job, the idea came to me when I arrived wet again that I wanted to apply this knowledge to my brake problem. I wanted to stick with PETG for the material choice, as I'm very impressed with its braking properties and I know that PETG is also flexible and durable enough. Now it was time to modify the CAD design again and find a way to integrate the "living hinge". First, I made sure that everything around the bend area was equally stable to ensure that we were bending properly at the hinge and that the flex was evenly distributed throughout the structure, distributing the elastic deformation over as large an area as possible.

2025 Improved Version + Update

Since the second version has now been in use for over six months and is reliably performing its function every day, and the wear on the wheel during braking remains within acceptable limits, I am still very satisfied.

The only remaining problem I see is that during prolonged braking, the PETG gets too hot and becomes somewhat soft. This doesn't affect the braking performance, but the plastic deforms and now causes loud noises with every hard braking maneuver. I think the PETG has hardened on the braking surface, but I still don't want to risk having problems with the brakes on a long uphill run. Therefore, I want to use my new favorite material, PCTG, a modified PETG that is stiffer, more heat-resistant, and therefore better suited for use as a brake, while also retaining all the positive properties of PETG, such as its easy printability. Conclusion If you want something to work properly, you simply have to make it yourself! The self-developed brake not only works better than the original in rain and snow, but its function as a mudguard is also better, so it's an improvement in all areas. The plastic even seems to be more durable than the metal flex brake, so the brake could also find its place in a stunt scooter in the future.