4 July 2021 Update: I created an improved version of a QL3.1 security clip, see: https://www.thingiverse.com/thing:4900666

I have a set of Ortlieb bags for my commuter bicycle that use the QL3.1 mounting system. These work great, are convenient and easy to use, and give the bag a low-profile for carrying off the bike. However, they do not have a 'factory' security option. I often park my bike at the grocery store, etc, and want to deter casual thieves from stealing my bags.

So, I designed these clips. You'll need to use both right and left (included in the pair files) clips. If you use only one the bag can still be easily removed. This clip just prevents the Ortlieb mechanism from opening. Obviously a thief with any time or motivation will figure this out quickly and remove one or both of the clips.

The way these snap on is a bit tricky, as the intent is to create something that stays put and doesn't easily fall off when riding. If you put them on correctly, they will easily slide and click into place.

Be sure to test to verify you actually have them snapped in place before riding off! And again, a determined thief will still get your bags. These clips are a band-aid at best.

As always, I included Solidworks 2017 files for your re-mixing fun.

Prusa

I3 MK3S

No

No

0.2

40%

I used PETG for toughness. Nylon might be even better. I chose 40% infill for strength, I'll see how this works and re-print with a higher fill % if needed.

I used black as I wanted these clips to blend in to the rack and not be obvious.

These are designed to easily print with no raft or support. You may have to properly re-orient the file before printing.