Well...
Standard Physics says that one of a few basic things have to be occurring for this to be happening to you, Pulse..
--your spokes are stretching (highly unlikey)
--your hub is expanding (again,... not likely)
--your spoke/nipple threads are slipping (more likely)
--your rims are caving-in (most likely)
Yoli had this happen to her very recently, and the culprit ended up being that the 'eyelets' or nipple-sockets in the rims were overstressed, and concaving inward. (she said with a magnifier you could see lots of little micro-fractures around the holes) There's also a pissibolity that your spoke threads are stripping on a few over-stressed spokes. (if this is the case it will happen more frequently with less riding each time.)
Examine your rims carefully, look for evidence of movement... If you don't see any, try to 'track' what's happening with each wheel by 'marking' the problem spokes, each time you adjust them. If the same spokes start showing up as the same trouble-makers each time, try replacing them (nipples too!) and see if that fixes it.
Sometimes the cause is materials failure, most of the time the cause is over-tightening. When the materials won't meet our extremely high demands, we must either lessen our demands, or improve on the materials. Always remember to loosen when you true, as well as tighten, and this will happen far less. (or get some composite rims - no spokes at all!!)
Of course...
With alternate Theoretical Quantum Physics, your spokes, rims, nipples, hubs, etc. all may gain their very existence purely through your mere observation of them... So if they're screwing-up, then all you have to do is
observe them better, dude !!! (
..squints eyes real hard!! )
