I only ever see bears riding gravel. I've seen more bears that way than hiking in the same areas. I'm not afraid of a black bear when I'm on foot, but cyclists don't move in a way large predators recognize as human.
A yearling black bear ambled across the road in front of me a while ago. I didn't know if there was a mama nearby. Running from a bear engages their predator instincts and I didn't think riding off would be wise so I stood for a few minutes ready to lift the bike overhead to look bigger. But there was no mama bear, so I finished the ride and got a great story out of it.