I had a pet wolf, long story but gave him a chance rather than see him killed outright. Bicycles and motorcycles caused a strong reaction in him that made him try to chase them. I could keep him under control, but it was difficult. That is the only time that he was difficult to manage. No other stimuli sparked anything similar to how he reacted to these two things.

I agree with Aksar that the strange part of the story is how the wolf stayed at the bike even when there were more people around. The wild wolves I have seen have all been very shy, curious but shy. I have encountered them alone and on foot in remote areas and never felt threatened by them. The fast moving bike could resemble normal prey, but they seem to recognize humans as different. Maybe it is the fast movement that sparks the hunting instinct.