Well i dont know. Good to hear so many creative tips that actually work or work.

So far i think i have to choose pepper or ammonia, pluss getting of the bike and use my bike as a big weapon and have a clear loud angry voice, maybe it would do.

Bears are more easy to temp than insane dogs, but its something with that voice..and a threat.
Like a fellow Norwegian citizen named Lars that completely crossed Canada north areas by foot and skies some years ago:

http://www.youtube.com/watch?v=hFGwX-BjHX8