OK. How does one get stopped? In the vast majority of cases I heard about its lack of situational awareness. After that, the only way one can be surprised is if he is forced through a blind spot which gives the attackers a place to hide WITHIN STRIKING DISTANCE, or he stops willingly because of subterfuge. example: My buddy is hurt, we need help, can I use your phone, etc.
Lets deal with the last one first. A second person may even be lying on the ground to sucker you in. First off, If you decide to stop (most people would), stop well out of reach of these people and dismount from your bicycle. You are now in a better position to defend yourself. Hopefully your weapon is on YOU and not the bike. Try not to put yourself between two people or have your back to one of them. Don't be afraid to take charge of the situation. If the people truly need help, they will welcome this and if not, their intentions will be made more clear. Its also OK to be blunt: Your too close to me. Stay right there. Don't come any closer. All these tactics will buy you time to assess and manage the situation.
Now, the blind corner or place to hide near the trail scenario.
Again, they can just step out in front of you to stop you assuming you won't run them over; do so! Then immediately dismount on the side away from other assailants, so they have to go around the bike to get to you. If its a gang situation you'll have to decide in the moment based on other factors.
If there is a physical barricade you are forced to stop; dismount away from the larger number of attackers (if just two, pick a side).
IF someone is going to pull you from the bike, they will have to do this from either the side or behind, else you could just run them down; stopping you probably, but also taking one of them out of the fight.
If they grab you from these positions (side, behind), drop the bike, forget your weapon (you don't have time enough) for the moment and concentrate gaining distance from the attacker. How do you do that? By moving in CLOSER to him, hurting him badly, then moving back. That means you must dismount from your bike on the same side as the attacker. Dismount TOWARD him. Besides remember he has a hold of you so that's really the only way you can go unless you waste time by breaking his hold. This puts you at the advantage giving you the chance to disable him. If, as been suggested, he rips you off the bike to try to throw you on the ground, let him. There are still things that can be done to him by anyone with a modicum of training. For instance, he grabs you around the neck from your left side, pulling you toward him. Forget the bike, lean into him and bring you right hand across your body, behind his head, & hook your fingers into his right eye socket * pull back and down. I can almost guarantee he will be out of the fight. Even for the untrained, with a strong will to fight you can prevail. Remember they are expecting you to not have a plan and be submissive. Don't be!
These ideas don't cover all possible scenarios but are a place to start. Play what-if all the time; I think that's why most of us are here on this site.
Sorry about the length of this.
Lets deal with the last one first. A second person may even be lying on the ground to sucker you in. First off, If you decide to stop (most people would), stop well out of reach of these people and dismount from your bicycle. You are now in a better position to defend yourself. Hopefully your weapon is on YOU and not the bike. Try not to put yourself between two people or have your back to one of them. Don't be afraid to take charge of the situation. If the people truly need help, they will welcome this and if not, their intentions will be made more clear. Its also OK to be blunt: Your too close to me. Stay right there. Don't come any closer. All these tactics will buy you time to assess and manage the situation.
Now, the blind corner or place to hide near the trail scenario.
Again, they can just step out in front of you to stop you assuming you won't run them over; do so! Then immediately dismount on the side away from other assailants, so they have to go around the bike to get to you. If its a gang situation you'll have to decide in the moment based on other factors.
If there is a physical barricade you are forced to stop; dismount away from the larger number of attackers (if just two, pick a side).
IF someone is going to pull you from the bike, they will have to do this from either the side or behind, else you could just run them down; stopping you probably, but also taking one of them out of the fight.
If they grab you from these positions (side, behind), drop the bike, forget your weapon (you don't have time enough) for the moment and concentrate gaining distance from the attacker. How do you do that? By moving in CLOSER to him, hurting him badly, then moving back. That means you must dismount from your bike on the same side as the attacker. Dismount TOWARD him. Besides remember he has a hold of you so that's really the only way you can go unless you waste time by breaking his hold. This puts you at the advantage giving you the chance to disable him. If, as been suggested, he rips you off the bike to try to throw you on the ground, let him. There are still things that can be done to him by anyone with a modicum of training. For instance, he grabs you around the neck from your left side, pulling you toward him. Forget the bike, lean into him and bring you right hand across your body, behind his head, & hook your fingers into his right eye socket * pull back and down. I can almost guarantee he will be out of the fight. Even for the untrained, with a strong will to fight you can prevail. Remember they are expecting you to not have a plan and be submissive. Don't be!
These ideas don't cover all possible scenarios but are a place to start. Play what-if all the time; I think that's why most of us are here on this site.
Sorry about the length of this.