setting help please

I want to start taking picture of moutainbike riders as they are flying down the trails. What are some of the setting that I need to capture the shots? I have the 18-70mm 55mm kit lens and a 1.7 49mm prime lens. Any help would be great.

I would recommend shutter priority mode. If there's good light, you can really freeze the action with faster shutter speeds. You can also do some creative things with some motion blur and panning with slightly slower shutter speeds. Work with what you get for light, location, and action and experiment with it.

I remember somebody on this forum posting good pictures, and he was using 2 flashes I think. One on the camera to get the eyes of the rider (instead of a shadow) and another a few feet away to iluminate the rest of the rider. I'll try to find the post