SD stands for SQUARE DRIVE
All conventional floating brake rotors use a circular rivet to attach the rotor blade to the inner hub. The SD-SystemTM uses a square-sided rivet with many advantages.
The theory behind SD-System Square Drive and how it works:
Under the heat of braking, a rotor blade expands or shrinks in both its diameter and bandwidth causing the inside of the rotor blade to shrink radially inwards towards the hub. With circular buttons, as the rotor shrinks, it will contact the inner button and cause the rotor to tighten and either be distorted sideways causing either brake pulsation or spongy brakes.
The SD-System Square Drive of square-sided buttons means that the rotor can expand inwards and outwards unrestrained and that perfect rotor functionality is retained at any speed or load. Not only does this extend the lifetime of the rotor and prevent distortion failures, it keeps the rotor blades perfectly true and flat throughout their life cycle and technically the only reason for a rotor to need replacement will be impact damage or over a VERY EXTENDED number of miles possible rotor wear limits being exceeded. This means that a rotor equipped with the EBC Brakes SD-System could last 5-10 times as long as a conventional rotor built with circular buttons.
A further advantage of the SD-System is that the drive forces under braking are transmitted over a LINE CONTACT on the square side of the button compared to the point contact of a circular button. Extended use with a circular button and its point contact will mean that the rotor could shake loose over a period of time in the drive direction. Slackness of the rotor blade relative to the inner hub is a major negative and can cause rotor “throw-out” and lead to severe vibrations at speed. The SD-System maintains close tolerances of the rotor in the drive direction over a far longer period thereby extending rotor life.
Watch this video to see EBC Brakes has not only delivered the LIGHTEST Brake rotor on the planet but has completely eliminated rotor vibration problems. For example, the latest 08 Suzuki GSXR600 front rotor part number 59210 37H00 weighs 1502 grams, EBC equivalent MD3100XC weighs just 1260 grams, that’s almost half a kilo saving on unsprung weight per bike.
