Well, there is some disagreement about rear-brake usage, even among world-class roadracers. The difference between the street and track comes down to speed and the intensity of the lever-grab. There's typically a significant velocity differential between the street and track environments, so when the front brake is used relatively vigorously on the track, the forward chassis pitch that occurs is dramatic, which usually has the rear tire skimming the pavement-and sometimes hovering inches above it. The rear brake isn't of much use then. Really fast (read: not smart) street cornering-and commensurate high-intensity braking-would result in a similar situation, meaning the rear brake wouldn't be of much use, especially during the first 75 percent of braking, which is when most deceleration occurs. Most of our staff uses the rear brake all the time on the street, mostly because we leave true, track-spec speeds (and braking) for the track. And most of us ignore the rear brake on the racetrack, but again, there are racers who use the rear brake to affect the chassis and traction at racing speeds. They're better men than us, for sure.