Bicycle splash guard

Update 24.04.24: deeper hooks, slim now recommended default

A splash guard that extends the mudguard of your bicycle. It can significantly reduce the dirtying of the bottom bracket and parts of the drivetrain. No tools or modifications at the bike needed. There is a regular and a slim version.
There are 3 parts: 

• A clip that sits on the inside of the mudguard printed best in ASA or PET-G.
• The splash guard that is fixed with the hooks of the clip, printed in flexible Material.
• A splash guard test file to check whether the dimensions are correct without having to print the whole splash guard.

Preparation

There are two examples for SKS Bluemels with 58mm width and 40mm width for the regular version and three examples for the slim version. To adapt to your specific mudguards get Freecad and measure the height, width and thickness:

In Freecad, open the spreadsheet and adapt the red parameters:

Change to the Mesh design workbench (View -> Workbench -> Mesh Design):

Select the three refined shape copies and click "create mesh from shape". The meshes always have to be rebuild if you change the dimensions.

The following settings seem to provide enough detail without a too big Mesh size:

You can now export each mesh as stl file:

You can print splash_test to check whether the dimensions are correct without having to print the whole splash guard.

You can play around with the splash thickness for different flexible filament hardnesses and the splash stretch factor for a tight fit. The clip has to be re-meshed and printed in this case, since its dimensions depend on the splash dimensions.
 

Printing

The clip is best printed with weatherproof material as ASA, but PET-G and PLA should be fine as well.
The splash guard is printed in TPU with 96 Shore A hardness. Other flexible Filament should work as well.
There are g-code files attached, but I recommend to slice yourself. You can use the standard settings for the respective Filament, maybe cranking up the speed for the flexible a bit. For the clip you can increase the infill to 40%.

• Layer height: 0.2mm
• No supports
• Infill: clip: 40%, splash guard: 15%

Installation

Make sure that your mudguards are mounted with enough clearance to the tire. Put the clip between mudguard and tire with the sharp edge facing down fitting closely the end of the mudguard. Hook the splashguard with the holes into the hooks of the clip.