The first disc brake to use oval pistons—ever. As in worldwide, in any application of disc brakes from F1 cars to Super Bikes—the mega powerful Formula RO Disc Brake pushes stopping power to new, uncharted levels in a lightweight package. While multi-piston calipers have been the go-to layout when power was the goal, they suffer from complex manufacturing, additional weight, and more moving parts (read: maintenance). The demands of top-tier downhill mountain bikes require as little mass as possible without hindering power or strength, and the oval pistons in the RO's caliper provide just that.
While an oval piston is the highlight of the RO, the pistons' heat-ditching technology also deserves attention. Made from an ultra-stiff composite, the piston is concave on the fluid side to increase heat-transferring surface area, while the pad side is grooved to promote a cooling air flow. Aside from the surface area maximizing oval piston, the RO's caliper is a monobloc design, meaning there's no seam to flex when applying eyeball-elongating stopping pressure. The caliper has venting windows both top and bottom to keep things from sizzling on hot summer-time lift runs—the top vent also allows easy pad change with the wheel still mounted.
Up on the bars, Formula employs its high-capacity forged aluminum radial master cylinder. This design offers an excellent leverage ratio, minimal flex, and maximum fluid storage. It also allows you to run moto style without swapping lines or affecting bleed port access. Formula's Tool Free Reach Adjustment knob allows simple tuning of the forged aluminum lever blade for optimum ergonomics, while The Feeling Control System makes tweaking of lever stroke or compensation of pad wear a simple endeavor.
In between the groundbreaking caliper and proven master cylinder resides a lightweight woven polyester hose that resists expansion from heat and line pressure for a nice, consistent lever feel. Formula uses DOT 4 brake fluid because of its resistance to thermal expansion, moisture absorption, and the quality control inherent with DOT-approved products, no matter what brand or where you get it.
At just 361 grams for a front brake with rotor, the Formula RO Disc Brake achieves a weight that’ll ruffle feathers of dedicated cross-country brakes. But, don't let that weight-weenie factoid dissuade you from maching double black diamond runs with the RO—this is a DH-oriented unit. The RO is packaged with all the pieces needed to set up one brake on one wheel except for rotors and adapters (sold separately)—it's a pre-bled lever/hose/caliper with pads.
Please note: almost all hydraulic brake lines need to be cut to size before a bike is properly shod with hydraulic disc brakes. You'll need a quality cable-cutter like the Park CN-10 and a spoke to first cut and then de-crimp the housing.