I posted about something similar to this here a couple years ago. Seems every time I get to a certain level it flares up again. I actually saw a doc about it once, in fact I was in there to get my knee fixed
and I told him about this, and he actually asked which one I wanted to get fixed first! Anyway, you might do a search on "Greater Trochantus" and see if you can dig up something. Mine flared up recently once again after I pushed the pace a bit too much trying to keep up with the roadies in the latest challenge, but after just a few days of backing off it is much better. Also, I regularly ride 3 different bikes and it does not seem to be any worse (or better) on any of them, so I don't think that's the problem... Good luck.