oh, not that I bike in the west, but I remember some friends of my wife in the Banff area telling us how one must be much more careful of surprising a bear when you are on a bike, as the approach time can be so fast so little warning to the bear. and henceforth risk of a scared, pissed off large mammal with big claws.
Only a problem on trails or partly overgrown roads, as I earlier stated, cougars as well..... 90% of the main forestry and logging roads have the brush cleared quite a ways back from the road; any that don't you should be cautious in case of approaching vehicles anyway.