An AirTag mount that sits hidden under the bottle cage on a bike. The mount (including the AirTag) is thinner than an actual AirTag! See “AirTag Preparation” below for more info.

The mount is made of two halves. The top half gets screwed (with a thread on the model) onto the bottom half, locking the AirTag into place. I've been using this on four different bikes for a total 8 years combined and no water ever got in, even in wet and snowy Switzerland!

Text can be added to the mount. To edit the text, use the Onshape document and edit the last feature ("Surface Text 1").

Print Instructions

Both halves are only one layer thick at their thinnest point, so make sure your first layer is tight (use this if you need inspiration).

The mount in the pictures was printed with a 0.4mm nozzle, 0.15mm layer height (first layer: 0.2mm) in Prusament PC Blend Carbon Fiber Black.

AirTag Preparation

Since the final mount is actually thinner than the AirTag, some magic needs to happen first to shed some of that AirTag thickness.

1. Remove AirTag battery cover

Start by removing the battery cover (press & twist) which will save a couple millimeters. The mount will act as a battery cover. You can dispose of the original cover.

2. Sand down until speaker

Don't worry, AirTags don't have feelings (I think). By sanding down the top part of the AirTag (until the speaker shows) saves a couple millimeters. The AirTag will still be functional (including sound, for mysterious reasons) though that will definitely void your warranty.

3. Clean up & Grease thread

Apply some grease/lube on the thread. The tolerances are tight and this will make it easier to screw both halves together. In theory it should also make everything watertight but don't quote me on this. 

(Note: if for some reason you need to adjust the tolerances, open the Onshape document and edit the Thread/Thread [Boolean]/Offset distance)

4. Insert AirTag

Insert the AirTag as shown in the pictures (notice how the inside of the two halves are slightly different, since the match different parts of the AirTag).

5. Screw top cover

Align the thread on both covers, apply some pressure and start screwing. Once both covers align perfectly (with no gap between the covers) you can mount your AirTag on your bike!