Using technology developed and refined in the first generations of hydraulic road disc brakes, the Ultegra grade hydraulic disc brake (ST-RS805) lives up to the Ultegra groupset ethos of ‘trusted reliable performance with advanced functionality, smoothness and ergonomics.’
Shimano’s new 105 and Ultegra grade hydraulic road brakes use a mineral oil reservoir housed in a compact and ergonomic mechanical lever with a 10mm reach adjustment to suit larger or smaller hand sizes.
Gear changing is handled with light and minimal finger movements of the two levers, resulting in a positive, clearly defined click and precise gear engagement.
Hydraulic hosing carrying the mineral oil features the improved cable routing introduced on the ULTEGRA hydraulic system last year, with the hose running down the inside of the caliper for a neater and more aerodynamic design. Set up of the hydraulic system is simplified with the option to funnel bleed using Shimano’s J-kit system.
The new Flat Mount front fork and rear stay fitting (BR-RS805 and BR-RS505) also brings aerodynamic advantages by introducing a closer fit between the caliper and the frame, reducing the need for visible mounting bolts. This new design allows consumers to move away from the mountain bike history and look, which has been used until now, using a method better suited to high performance road bike riding.
Together with the lever and caliper the new SM-RT81-SS 140mm rotors and pads allow for consistent braking performance through all weather conditions with innovative ICE heat management technology and adjustable stopping power that can be tuned to the riding conditions, terrain, rider’s size and ability.
The cooling ICE technology found on the SM-RT81-SS rotor comprises a three-layer sandwich structure of stainless steel and aluminum to allow heat to dissipate rapidly from the surface of the disc rotor, reducing the risk of rotors becoming hot-to-touch after extended braking whilst descending.
After introducing hydraulic disc brakes for road usage in 2013, then making it available for mechanical shifting in 2014, today’s Shimano 105 grade hydraulic disc brake (BR-RS505 and ST-RS505) is fully compatible with Shimano’s mechanical 11-speed DURA-ACE, ULTEGRA groupsets, and of course its 11-speed 105 groupset.