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All About Our AXS Controls
The Development of our Most Effortless Brakes
SRAM RED AXS shift-brake controls are the nerve center of your riding experience. Not just for shifting and stopping, they serve as a comfortable contact point for your hands, and a convenient way to interact with your head unit. How did we achieve breakthroughs for braking quality and ergonomic comfort while also introducing new features? Years of development and testing from a team of engineers, industrial designers, and riders including some of the best professional racers in the world. Learn all about AXS controls and how we did it.
Ergonomics
SRAM RED AXS deploys the most comfortable hood we’ve ever created. Independent Reach Adjust and pad Contact Adjust help you tailor your brakes not just to your hand size, but to your personal preference for brake feel as well. The hood shape fits a wider range of hand sizes and provides better finger wrap while also preventing finger pinch during hard braking.
To work with modern setup trends, the pommel, the bump at the front of the hood, flares inward for better comfort and less hand fatigue on long rides, and the brake lever flares outboard for easier access from the drops. For even better braking from the hoods, the brake lever pivot was moved upward to increase leverage, and the result is easy one-finger braking with 80% less effort than before.
Bonus Buttons open up more possibilities. Located on the inside of the pommel, Bonus Buttons let you shift with your thumbs or swipe through your head unit without taking your hands off the bar. You can even use them to actuate an AXS dropper post. Program them how you choose through the AXS app.
These breakthroughs didn’t come overnight. The new shape of the RED AXS controls represents a four year long project in our industrial design department to carefully quantify riders’ needs and create controls that work for everyone. The top priority, according to Industrial Design Lead Nathan Luman, was “increasing the usable range.” After measuring the hand size of numerous athletes and test riders, the ID team built a database of that sizing data and set about designing a hood that would provide comfort and stopping power for all hand sizes, in every adjustment setting, even as pads and rotors begin to wear.
Using 3D printers for rapid prototyping and testing allowed the team to create nearly 40 hood variants over the project, gathering feedback on indoor trainers with each generation. Rideable prototypes were spread equally across the entire pool of hand sizes to ensure the best data.
Testing led to further improvements. The pommel moved inboard to reduce the chance for hotspots and account for natural hand roll-in. A seven degree rise was chosen as the optimal hood angle to create a neutral wrist position. The team’s CAD database of hand sizes allowed for quick development and testing to arrive at a thinner and longer shift paddle shape that eliminated finger pinch during hard braking, and was also more accessible from multiple hand positions. The hood was widened outboard as it approaches the clamp to keep pressure off the ulnar nerve and prevent numbness. After further ride evaluations, the design was set.
How we use drop bar bikes has changed, and even pros spend more time on the hoods than ever before. So easy braking from the hoods was a must, leading to a brake pivot that was higher and further forward than previous designs. This led to a new push-piston brake design from the engineering team that could neatly fit into the reduced circumference of the grip. “I liked to think about how natural and powerful it is to one-finger brake on a MTB setup, so we just had to turn that power and comfort 90 degrees,” Luman says.
When Luman asked engineering for a design that fit their dream specs, they were ready. Design Engineer Patrick Gruse had worked on the design of the S-900 Aero HRD Disc Brake in 2016, and recalled what happened to the brake feel when they raised the brake pivot to help the internals fit. “It felt like magic,” he says, and he started working on bringing the concept to a dropbar brake in his spare time. Knowing they were on the same page was encouraging, and they teamed up and developed a working prototype. “It was 3D printed in purple filament and affectionately became referred to as “Barney,’” but everyone who rode it loved it, says Gruse.
Power
RED AXS controls have engineering breakthroughs beyond a new piston design. Grams were shaved everywhere possible, with a new set of shift-brake controls and calipers coming in 83 g lighter than the previous generation. Not just lighter, the calipers are also a new stiffer design, thanks to tightening the bolt architecture that holds the two halves of the caliper together. The piston was moved outward to optimize the center of pressure on the rotor. “Between the stiffness gains and the center of pressure move, we gained a ton of power, and the caliper is 13% lighter, 11% stiffer and the center of pressure has been shifted out, radially, by 1mm - these three factors help increase total power and make more power available earlier in the lever stroke,” says Gruse. More power, with 80% less effort braking from the hoods and 33% less effort from the drops, for an effortless ride.
