There is a triathlon that will probably interfere with access to the Cathedral during service ringing. The running segment of the course is along Bayshore Drive.
The race is scheduled to start at 7am, and based on usual triathlon times people will be running on Bayshore Drive from about 8:30am to 10:30am.
It appears that the only unaffected access to the tower will be along the Venetian Causeway. The Julia Tuttle causeway will be obstructed from about 7:30 to 9:30, and the MacArthur Causeway from about 8:30am to 10:30am.