Use technique more than gear. Start in Tv (shutter priority) and choose a shutter speed based on the look you want: around 1/250s or faster to freeze action, or much slower for panning shots to show motion blur. For panning, track the bike smoothly and keep following through as you shoot.

Try AI Servo/continuous AF first, but your lenses may not focus fast enough for motorcycles. A reliable alternative is to pre-focus on a spot where the rider will pass, then shoot as they enter that zone. You can do this with One Shot AF or manual focus.

If light allows, use a smaller aperture to increase depth of field, which gives you more margin for focus errors.

Most importantly, practice and learn the race flow. If you can anticipate where riders will appear, where they slow down, jump, or lean into corners, you’ll get more keepers. With a 550D, timing, pre-focusing, and panning are often more effective than relying entirely on autofocus.