Hey y’all,
I have a customer asking me to make a place for him to stash an apple airtag onboard their new frame, in a place where it won’t be obvious to a potential bike thief. So my plan is to hide it inside one of the tubes.
I’m curious if any of you have hidden an airtag inside a steel tube. If I do, will it still be able to transmit its location? The internet is giving me mixed messages here.
Whatever you do, make sure you can get it out again so user can change the battery!
Assuming the purpose is theft tracking:
Place it somehow (?) in the seat tube and lock access to the seat tube with a hexlox key on the seat clamp 
About a year ago I made this little puck on the lathe that fits into a BSA bottom bracket on the front of my cargo bike. I used vhb tape to attach an airtag to the back of the puck and have had it in my bike ever since. Don’t know how I would do it on a normal bike, especially since the diameter of airtags is somewhat large (Google says 31.9mm).
My experience has been that the steel tubing creates a pretty good faraday cage and that the airtag can’t really do its job as it normally would. It seems to me it lags behind the bikes location by a significant amount, anywhere from 15 min to a full day. It often tells me I left my bike behind even though I’m riding on it. So no guarantees it would help find my bike if stolen.
This is my buddy’s product. I have it on a couple of my bikes. Don’t even notice it’s there.
Blackbrush Airtag Bike Mount Hidden, Airtag Holder for Bike, Anti-Theft Bicycle Tracker Cap Compatible with Airtag & Tile Sticker, Hidden Mount for AirTag & Tile Sticker (AirTag Not Included) Amazon.com
Thanks log.zip - the frame acting as a faraday cage is exactly what I was worried about. A BSA bottom bracket shell is pretty thick. I wonder if a thinner tube wouldn’t be such a problem.
I had been planning on ovalizing a 31.7mm tube to make an extra big flat chainstay bridge. The bike isa classic touring bike with pretty long chainstays, so it would fit in front of the tire no problem. Then I’d drill a big hole in the underside with a 32mm holesaw, to allow for access, then I’d plug the hole with something like this: McMaster-Carr
The tube I’d use is much, much thinner than a BB shell, so maybe I’ll make a mockup and see what an airtag does inside it.
And Pax - I hadn’t even thought to check amazon for an off-the-shelf solution. Good tip! If the chainstay bridge idea doesn’t work, I think I’ll point the customer towards some of the amazon products - he’s a 3d printing enthusiast, so I’d guess he’ll borrow ideas from them and end up printing something for himself.
Thanks everyone!
I recently saw an ad for this valve stem airtag holder from Muc-Off:
I’m not sure what impact the tire and rim would have on the airtag’s reception, but it would certainly be a stealth and tricky for a thief to figure out location to hide one; though it’s utility would also fall off precipitously if/once the wheel(s) were separated from the frame.
Given that you can make a faraday cage out of wire mesh (that’s what they use when working with super-high voltages in big industry), I doubt a thinner tube will make any difference. It may be a little better, but still likely sufficiently poor as to render the airtag somewhat useless. A plastic or carbon fibre cover might be a better bet, but incorporating that into your frame could be technically and aesthetically challenging.
Anything metal (steel, aluminum, basically all things conductive) enclosing the AirTag will kill all RF signal, and it will be useless. You need something that is transparent to 2.4 GHz. So plastic.
Couple of notes with airtags, they are not really great for this particular use but they can be better with some work.
Like it was already mentioned, you will need to change the battery on them so place them somewhere where you can take them out somewhat easily, I take apart my bikes regularly so even inside the BB is not a problem for me but it depends on your customer.
They will chirp, if someone takes the bike the airtag will eventually start chirping and they will locate it fairly quickly, the workaround is to open up the tag and physically remove the “chirper”.
At this point it will be silent BUT if they do have an iPhone/iPad they will be notified that there is an unrecognized tag “following” them, this feature was added to avoid misusing of those tags, I am sure you can imagine plenty of bad/creepy/illegal scenarios.
Anyway, if the chirp sound is disabled, I feel it’s a pretty decent/cheap option.
GPS trackers have different issues anyway, there is no perfect solution unfortunately.
