Crank Cover for Mirider One

The crank cover on my Mirider One fell apart (it was a bit flimsy.)  This replacement is nicer!

It's made to match the original in basic dimensions - the cover diameter is 210mm and thickness of 9mm. The distance between screw centres is 91mm - the diameter of all centres is approx. 155mm.

Should also work for a Onebot S6, but check the crank measurements first.

Models

There are two main models for screw mounting options:

• Threaded holes for M5 x 8 screws (button head in stainless steel is a good option.)
• 3mm holes for the smaller, self-tapping screws from the original crank cover.

There is a model with no holes that can be scaled to possibly fit a different crank. (This needs its own holes adding after scaling.)

There are also STEP versions, as well as the FreeCAD file for full customisation.

Printing

PETG or ABS would be good choices. PLA is maybe a bit brittle and not so good for parts exposed to a lot of daylight, but it will still do.

A 0.6mm nozzle works well for reducing the print time and adding a little more density.

Three or more perimeters and plenty of infill will help for strength.

The M5 screw threads will print more accurately with thinner layers, but it's not too critical. Probably best not to go over 0.3mm.

If using a Prusa i3 MK2/3/4, the model will fit but there's no room for a skirt.  Instead, either:

• Don't use a skirt.
• Paint an outer seam on the model near to where the purge line ends.

• Add a 15mm, one-layer high cylinder with modifiers for no top and bottom layers and infill set to 70% Archimedian Chords.  Move it to the top of the parts list and set it near to where the first extrusion on the crank model starts (may have to check the tool paths on the sliced first layer.)

I printed mine with 0.6mm nozzle, 0.25mm layers, 3 perimeters, 30% cubic infill.  Also used two colours - black and then orange at about 3mm height (Prusament PETG) as these go quite well with the bike's colour scheme. The orange will show up oily dirt on the crank side, but the idea is that it can indicate when cleaning may be necessary.