Stromer Mudguard Extension V12 - ST2, ST3, ST5 and ST7

The issue with the original front mudguard of the ST2, ST3, ST5 and the ST7 (ST2: the new models with 27,5 inch wheels) is that it is a little too short for rainy road conditions. Without extensions, it is easy to get your shoes and pants wet.

The V12 model can extend the mudguard by 30 cm, 10 cm at the top, and 20 cm at the bottom. But you can set your length! The model is parametric, just enter your length in the spreadsheet of FreeCAD 1.0, export and print it!

The main difference between the V8, V9 and V10 models that this model is made for printing with TPU. The walls of this extension are therefore somewhat slightly thicker. Because TPU wobbles during printing, the higher the model becomes, the more it wobbles. 

It is recommended to print TPU very slowly! Look for a tested TPU profile! For the MK4S check this profile: https://www.printables.com/model/1285190-mk4s-tpu-profile-quest-for-the-3dbenchy-with-tpu 

If you use Eryone TPU you can use the print files for this model. 

The mounts are unchanged, and it is recommended to print these with PETG.

One extension consists of two model parts that can simply be screwed together, the mounts and a mudguard extension. It can also be printed without support. Except if you print a mudguard extension longer than 15 cm, a brim is recommended.

The extension is screwed onto the mudguard and not simply clipped on like the original part. This way it stays securely in place. The mudguard already has holes at the end that can be used for the screws.

You need the following screws and nuts to mount one mudguard extension together and onto the mudguard:

• 6x M3 hexagon nut
• 4x M3 x 20 mm Allen screw 
• 2x M3 x 8 mm Allen screw 

The nuts can be placed into the brackets with a longer screw, they should not fall out. But I recommend some water-resistant glue to secure the nuts in place.

The model was created with FreeCAD 1.0.