This implies you have to have more than one, is a rear brake mandatory on a fixed tt bike?
No, regulation 14c allows deletion of the rear brake as long as you have a lock ring (or equivalent anti-rotation device on tricycles). As a result of this poor wording, it is technically prohibited to ride a bicycle with an ISO 6-bolt sprocket in CTT events unless you also fit a rear brake. I feel an AGM resolution coming on...
No, regulation 14c allows deletion of the rear brake as long as you have a lock ring (or equivalent anti-rotation device on tricycles). As a result of this poor wording, it is technically prohibited to ride a bicycle with an ISO 6-bolt sprocket in CTT events unless you also fit a rear brake. I feel an AGM resolution coming on...