Being in Chicago has definitely made me look at self defense while cycling. First off the best protection is staying away from dangerous areas and staying alert. However, when some lunatic comes at you for trying to speak up against their smallmindedness, a non-lethal weapon may be needed. I have also had friends mugged by groups or hit buy cars and run off the road while cycling by muggers. Gotta love Chicago. I looked into a lot of different weapons to carry on me incase I need to defend myself as a last resort. Manrikis, maces, knuckles, knifes, and even a small collectable baseball bat. Turns out my long kryptonite hardened steel chain would definitely dent some skulls if it ever came down to it and it would be good for defendeing against a group. It's basically a bicycle mace! And wouldn't ya know it doubles as one of my bike loocks [= It also doesn't add any extra weight to your bag becuase you already carry it as a lock. If they have a gun your F'ed but I guess you would be no matter what anyway. I had a situation last year where I was being apporached by some thugs and I pulled that sucker out and they started walking the other way real fast. So i recommend staying alert and be careful and smart. If that doesn't work, yank out that bicycle lock!