I use a combination of bell and verbal warnings that I intend to pass. I generally use verbal if I see the person does not have headphones on and is a not in a group. Chances are if you speak clearly enough – they will hear and understand you. If it’s a group of people or if the trail user has headphones or seems distracted – I’ll give them a bell warning in advance.
I also find it helpful if you’re riding in a group and if you are the lead that you give a quick number of passing cyclists so the user doesn’t assume it’s just you and then moves back closer to center. For example if my wife and I are riding and I’m in the lead I’ll approach and say a quick “Two bikes on your left”.
