I've done a fair bit of mountain bike photography, mostly for race coverage, but some for my portfolio of prints that I sell through this website and other online purveyors of Wall Art for sale. I love snapping photos and shooting video of people ripping around on fat tires, launching off jumps and tearing around berms. But you know what? Shooting mountain biking comes with a ton of challenges. First off, you're trying to shoot someone speeding by you at a high rate of speed, or launching off a jump 20 feet in the air, and more often that not, all of this is happening in some dank woods on the side of a mountain, miles away from anything. When you set out to shoot some mountain bike stuff, you better be prepared for anything that comes your way and be ready to capture any and all action.
On that note, and since I'm not the guy to find himself in FRONT of a camera, here's a video from The Loam Ranger that goes over some of the more simple techniques on how to achieve awesome shots next time you're out in the woods. Hope this helps!
Here are some examples of what using the above techniques can get you. All of these shots were shot by me, at various mountain bike events.
And here are a video clip using a GoPro camera trackside I shot for a larger video project I am working on. Super wide angle, panning along with the rider, and slowing the action down at the peak of the action for a super cool, dramatic effect.