Clarks Hydraulic Disc Brakes. Hydraulic disc brakes offer the cyclist the most powerful and consistent method of stopping across all weather conditions. Almost unaffected by wet weather and dirty environments, hydraulic disc brakes are fast becoming the brake system of choice for all cyclists. Hydraulic systems offer the rider extremely consistent braking giving a very positive and reliable braking feel. Heat, caused by braking friction is quickly dissipated away from the pad and rotor contact points, through efficient rotor design. The Clarks range of hydraulic brake systems offer the enthusiastic rider all the features of high end systems but at a fraction of the price. All available with various rotor sizes from 160mm to 203mm and in both IS and PM fitting options. All Clarks brakes are tested and approved to BS EN 14766-2005 (CEN) and ISO4210.