12 March, 2024


By: Allied Cycle Works

Testing SRAM's new Flight Attendant on the BC40

The BC40 likes to party. SRAM’s Flight Attendant makes it party smarter.


We’re stoked to be co-launching the new SRAM Flight Attendant, the world’s smartest damping system. It uses a machine-learning algorithm to monitor every ride, adjusting its own ability to auto-adjust your shock and fork, creating a personalized profile tuned to your specific ride preferences and abilities.

But… why? Simplifying decisions and minimizing what SRAM calls “decision fatigue” during high-intensity rides and racing. Here’s an anecdote to illustrate the point: According to SRAM, Nino Shcurter took Flight Attendant to a recent World Cup race. Over the course of those 90 minutes, he’d typically adjust his suspension ~300 times. In the same 90 minutes, Flight Attendant adjusted it 1,325 times.

That means Nino had 300 fewer decisions to make while the blood was all in his legs, and had 300 fewer distractions from the course. Meanwhile, Flight Attendant multiplied his efficiency by micro-adjusting his suspension state 1,000 more times than he would’ve, matching the suspension to the terrain and his pedaling effort automatically and continuously throughout the entire race.

Nino’s obviously in a separate class, but SRAM’s testing numbers give an idea of what the impact might be on racing times for us mortals, with average speeds 1.8% faster for Flight Attendant users – that’s almost a free 100 seconds in a 90-minute race.


Those are impressive metrics, to be sure, but cycling is so often premised on these generational changes that toss around percentages and grams that, while they make sense on the page, really don’t translate to noticeable improvements in ride quality or performance. Like, you know it’s lighter, stiffer, and more aero by 4% or whatever, but when it comes to being on a bike, those differences are literally marginal.

Rather than just repeat marketing materials, we insisted on taking this system for an extended test flight, and we can confirm: the difference is real and very, very tangible. We’ve gotta say that it's pretty incredible. Flight Attendant is absolutely an upgrade in an industry that tends to oversell that idea.

Like the rest of you might be, we were initially very wary of a bike that could "think for itself." We’re kinda control freaks about our gear – no surprise, considering our line of work – so we generally always want to be in control of every aspect of our bikes. While we haven’t been able to spend much more than a weekend with the new Flight Attendant, we didn’t even need that long to be convinced. Our local trail systems feature a lot of terrain types, packed pretty tight in some places. After about five minutes of diverse trail riding, Flight Attendant had crushed our misgivings.

Getting out of the saddle to push watts on a smooth climb? Before you even think about it, you’ll hear the suspension lock. Veering off onto a technical alt-line? Flight Attendant has already opened up or gone into pedal mode. Transitioning from a very rough downhill to pavement? It locks out in less than a pedal stroke.

You can’t surprise it, because it’s not guessing; it’s reading inputs from across your machine, so it knows exactly what you’re doing, even when it hasn’t built a full portrait of your riding style with Adaptive Ride Dynamics. (Which it will do, too – more on that later.) It does everything we do with a remote lockout, but it does it before we could do it ourselves.

1,342 suspension changes vs 300. Half-a-minute off a 90-minute World Cup race. The satisfaction of intuitive, auto-adjust damping that learns from you and grows with you. We’re sold.


The new Flight Attendant reads inputs from across the SRAM AXS system to dial your ride across Lock, Pedal, and Open settings. While the auto-adjust aspect isn’t exactly standard, the settings themselves are – with one exception. Unlike with cable-actuated dampers, the wireless Flight Attendant supports split states between fork and shock, mixing the three damping settings as you see fit rather than running both in the same setting.

That’s basics out of the way, so now it’s onto the big changes for the new generation, headlined by the new algorithm’s ability to learn from every ride you do and automatically adjust to adapt. It teases out your preferences and your abilities, and it actually grows with you as you get stronger and more capable.

SRAM calls its auto-learning, auto-adjusting system Adaptive Ride Dynamics, and it uses all that learnin’ to personalize four Effort Zones, ranging from Sprint to Low Effort. These are again pretty self-explanatory. The Sprint Zone tilts toward Lock, the High Effort and Medium Effort Zones gradually shift from high efficiency with some squish to high squish with some efficiency, and the Low Effort Zone is about comfort and tilts toward Open.

The personalized Effort Zones are themselves influenced by bias – in this case, Bias Adjust, a feature that lets you coach your Flight Attendant toward Open or Lock in order to account for personal preference or terrain for the day. This setting can be dialed through the app, adjusting across five positions from Positive (more stiffness) to Negative (more compliance).

Finally, to get the most out of the new Flight Attendant, SRAM recommends a power meter (not just a pedal meter) and an AXS rear derailleur and two-button AXS controller. Older SIDs and existing Flight Attendant will still work – you’ll just need a firmware update.


Ready to fly? Check out the BC40 XX SL, built with the new SID Ultimate Flight Attendant fork, SIDLuxe Ultimate Flight Attendant shock. It’s optimized with everything you need to get the most out of the new Flight Attendant.



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