We've noticed, and we're sure you're aware too, that disc brakes are sneaking onto mainstream road bikes. The waters were first tested on endurance and gravel oriented machines where aerodynamics and weight aren't huge criteria, and what didn't go unnoticed was the improved power and modulation in all conditions. The recent upswing in bikes within the pro peloton receiving disc treatment is in part due to the UCI, the governing body for international racing. Recently, disc brakes have been allowed for racing use, but frankly, it has some other pretty archaic rules when it comes to regulating bikes. Bikes must weigh at least 6.8 kilos which is a pretty easy feat to achieve with a racing frame, nice components, and the de rigueur carbon tubular wheelset. As early as 2003, when lightweight climbing bikes were the rage, mechanics would have to add dead weight to the bikes just to get them into compliance. Then the industry decided to chase aerodynamics as a way to add functional weight back into the frameset. Through advancements in materials and technology, now those bikes are easily lower than the weight limit as well. So, as a way to once again add weight gain in the name of functionality back into the bikes, disc brakes are being used to offer the racer a tangible benefit in braking performance with negligible weight gain and aerodynamic drag allowing for race-ready performance on aerodynamic speed weapons. Ridley's Noah SL Disc Dura-Ace Di2 9170 Complete Road Bike takes the speed bolstering design features it honed on its rim-brake version and pairs it with Shimano's powerful and well-modulating hydraulic disc brakes for a bike that can shatter PR's while stopping in total control. Capped off with Shimano's always much-lauded Dura-Ace Di2 drivetrain, this bike banishes any ideas or fears of overheated carbon braking surfaces or sub-standard braking in wet conditions so you can take advantage of the wind-cheating speed to go fast without fear of slowing down.
Although this Noah has been slightly tweaked and reinforced to handle the force dynamics of disc brakes, its oversized tubes still earn the SL suffix—which we assume denotes the industry superlative Super Light—through Ridley's inclusion of a mix of 60, 40, and 30-ton high-modulus carbon fiber. Both the Noah Fast and Noah top out at 50-ton, and the SL's inclusion of 60-ton means it can use less material at key points while maintaining the same efficiency, which in turn lowers weight. As with the rim brake model, the SL's different carbon moduli are placed in different areas of the frame based on desired properties of stiffness, weight, durability, and road-noise damping.
This targeted blend of materials is a common practice across the industry, though few manufacturers go to the extreme of using 60t carbon. The SL also features a tapered head tube for sharp tracking and efficient power transfer, and the PF30 bottom bracket, internal cable routing, and future-proof electronic group compatibility that are all but expected in frames of this level. Unlike other frames, though, Ridley incorporates its Future Aero Speed Technology (FAST) F-Surface design, which involves fluted channels running the lengths of forward-facing tubes to trip air into a manageable layer of turbulence. That tripped layer detaches later and more cleanly, reduces the frame's wake and overall wind drag.
The Noah SL's high-modulus carbon fiber fork looks distinctly different than other forks on the market, with an open channel running down the middle of each leg. This FAST F-Split Fork channel design is revolutionary in its ability to guide incoming air away from the spokes to reduce turbulence and drag, which keeps the airstream around the wheel smooth and fast. By pairing this fork with the FAST F-Surface design, Ridley claims that the Noah SL enjoys a 3-5% reduction in drag over frames without FAST design. This means more speed with less effort, all thanks to a little bit of surface air routing.