Do I have to know who all my team's runners are before I register my team?

No, but read on. If you register via Active.com, you will need to enter your information but can enter your team members' information later. However, because there is a cap on relay registrations (75), your team will not be guaranteed a spot until all of your runner forms and team information have been received. You can also register by mail (send team captain's completed application form and full team fee to register your team), but recognize that your team will not be guaranteed a spot until all of your runner forms and team information have been received. Each team must provide all team member forms, IDs (for masters teams), and runner rotation order for their registration to be considered complete.