I think I’ve found the best place to hide a tracker on my Brompton: in its front carrier block!
It does require a Pebblebee Tag, as AirTag and Chipolo One are too big to fit. Just make sure to leave a space on top for the locking mechanism to fit.
Edit: I was told that AirTags fit as well, so I guess Motorola Moto Tag might fit too, as I believe they are roughly the size of AirTags.
@axeleroy @brompton I fitted an AirTag in mine without any problems.
@ReCyclist @brompton Oh, they must be smaller than I thought.