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RockShox Introduces Automatic Suspension System - Flight Attendant Review 39

Constantly analyzing both rider and terrain input, RockShox's new wireless, electronic suspension system provides the most ideal riding platform at any given moment.

RockShox Introduces Automatic Suspension System - Flight Attendant Review

Every so often, an evolution in mountain bike technology comes around that drastically changes how we all experience riding for the better. There are countless examples of such technological advancements throughout the history of mountain bike development, with most recent examples including the lever-actuated dropper post, single front chainring drivetrains and the ever-popular, lower-longer-slacker geometry. In every situation, the perception of what was previously possible on a mountain bike gets shattered and a new expectation for performance is established. Well, get ready to mark your timelines because today, RockShox has released their wireless, automatic suspension system appropriately named Flight Attendant. Using a mixture of sensors and algorithms, Flight Attendant constantly analyzes pedaling forces and trail compressions to provide the best suspension platform in every situation. No pedal-assist switches to turn, no buttons to press. With a priority put on simplifying riding while maximizing overall efficiency, RockShox has developed a component system that could take us all one step closer to having one bike that excels across any terrain.

 

Strengths

  • Improves pedaling efficiency across any type of terrain 
  • Intuitive, fast changing system to match terrain and rider input
  • Descending performance of suspension unaffected by system
  • Ease of installation, setup and adjustment 
  • Clean and simple design

Weaknesses

  • Motor noise when adjusting between compression positions
  • Not available as an aftermarket component 

Flight Attendant Highlights

  • Automatic electronic suspension system
  • SRAM AXS-enabled components
  • 3-position compression adjustment
  • Adjustable low-speed compression, rebound damping and air pressure
  • Uses the same batteries as other AXS-enabled components
  • Flight Attendant fork options: Pike Ultimate, Lyrik Ultimate, ZEB Ultimate
  • Flight Attendant shock options: Super Deluxe Ultimate
  • System weight: 308-grams
  • Not sold as an aftermarket system
  • Only available as a complete system on complete mountain bikes sold my select manufacturers
  • Models equipped with Flight Attendant (at time of product launch): YT Jeffsy, YT Capra, Canyon Spectral, Canyon Neuron, Specialized Enduro, Trek Slash

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Why Did RockShox Develop Flight Attendant?

RockShox’s goal when developing Flight Attendant was to simplify the rider experience out on the trail. While the system is constantly analyzing data to anticipate the most ideal and efficient suspension platform, the rider is left with only the trail ahead to focus on. Squeezing every bit of fun out of riding should take priority and Flight Attendant is meant to enable riders to go faster and further with less energy expelled. RockShox also designed Flight Attendant to be used across any discipline of mountain biking. By analyzing rider input at the cranks, Flight Attendant can detect when a rider stops pedaling and begins descending. This is important because it means that Flight Attendant has no effect on the suspension during descents and only starts working its magic once pedaling or going uphill. This was done so that regardless of the type of mountain bike equipped with Flight Attendant, the descending characteristics are preserved. This factor alone is what makes Flight Attendant suitable for more than just cross country bikes with the most exciting benefits experienced when the system is applied to trail or enduro bikes. Now, Long-travel enduro bikes can pedal and climb with never before experienced efficiency and still maintain their familiar capabilities and characteristics on the descents. Finally, RockShox prioritized creating a wireless system that utilizes AXS-enabled components for simplicity, consistency and compatibility. Taking cues from SRAM’s AXS drivetrain and the AXS Reverb dropper post, Flight Attendant offers the same ease of installation and user-friendly interfaces to adjust components on the go or through their SRAM AXS App.

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How Does Flight Attendant Work?

So how the heck does this fancy new electronic stuff even work? Flight Attendant is made up of only three components: the fork control module, the rear shock motor module and a crankset sensor. Each component is equipped with sensors that together detect bumps, the pitch of the bicycle and pedal strokes from the rider. This information is then communicated to an onboard algorithm that analyzes both terrain and rider inputs every 5-milliseconds to provide the most ideal suspension setting. Based on these factors, Flight Attendant places the suspension in either an Open, Pedal or Lock compression position. RockShox's goal was to achieve a system that remains as open as possible for comfort and performance while leaning on the algorithm to find the best opportunities to lock the suspension for maximum efficiency.

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The fork control module is the mastermind of the Flight Attendant system. Located where you would typically find the external compression adjustment on a fork, the fork control module collects data from all Flight Attendant sensors to determine what compression position the fork and shock are in at any given moment. Powered by the same SRAM AXS battery found on other AXS components, the battery hangs behind the CSU of the fork. While the location of the battery does appear mildly problematic, RockShox ensured us that the majority of frame designs do not pose any clearance issues. Intentionally mounted within sight while riding, the top of the fork control module has five LED lights with Open, Pedal and Lock compression positions labeled. As the system changes to best match rider inputs and trail impacts, a green light will pulsate indicating which configuration the suspension is in. Flight Attendant will adjust the fork and shock individually which is indicated by having two green lights illuminated while riding. For example, if both the Pedal and Open positions are lit up, that means the fork is currently Open while the shock is in Pedal mode. 

Cyan lights indicates rear shock low-speed compression adjustment
Blue lights indicates fork low-speed compression adjustment
Purple lights indicate bias adjustment

There are also three buttons on the top of the fork control module that can be used to adjust low-speed compression on the fork and shock, adjust rider bias preferences and enable Manual Mode (both features covered below). Toggling between each adjustment is done by the middle menu button while the plus and minus buttons are used to fine tune each setting. All features can also be adjusted with SRAM's AXS App. The location of the fork control module can be impressively distracting as the urge to glance down and see what position the suspension is in can be strong. Riders looking for a pure, undistracted riding experience can put Flight Attendant into Dark Mode via the SRAM AXS App. In Dark Mode, the green lights will only illuminate a single time when a compression position change occurs. 

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The rear shock motor module is located where you would typically find external compression adjustments on the Super Deluxe Ultimate shock. The motor module is equipped with its own sensor that communicates terrain inputs from the shock to the fork control module. That information is then analyzed by Flight Attendants algorithm to determine what compression position the shock should be in. The rear shock motor module is also powered by a SRAM AXS battery. 

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The last piece to the Flight Attendant puzzle is the pedal sensor located inside the crank spindle. The pedal sensor collects pedal inputs from the rider and informs the fork control module when a rider starts or stops pedaling. This is the one component that is not powered by a SRAM AXS battery but instead uses a standard AAA battery. The pedal sensor will fit inside most SRAM DUB cranksets but is designed to work inside of XX1 and XO1 spindles. An important feature related to all three components is that they can be removed and the fork and shock will still function as normal. This was done by RockShox to simplify suspension maintenance and keep your bike functioning if aspects of the Flight Attendance system require servicing. Lastly, if any of the batteries die while out riding, the fork and shock will default to the Open compression position. 

Setup and System Calibration

Flight Attendant requires a one-time system paring and calibration before hitting the trails. Pairing Flight Attendant is similar to pairing other AXS-enabled components and is completed through the SRAM AXS App. After all components are paired and visible within the App, air pressure and rebound can be set for the fork and shock before calibrating Flight Attendant. Calibration is a simple process of sitting on the bike on level ground and then leaning the bike towards the non-drive side. The process takes maybe two minutes and allows Flight Attendant to determine where each module and sensor is located to interpret changes in the angle of the bike as you ride. The SRAM AXS App provides a simple step-by-step tutorial on how to calibrate the system as well. After the initial pairing, setup and calibration are complete, Flight Attendant will be set in auto-mode and ready to go the next time you ride. No waking up the system or turning on any of the components. 

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3-Position Compression Adjustment

Depending on trail impacts and rider input, Flight Attendant toggles between three compression positions: Open, Pedal and Lock. As mentioned above, Flight Attendant is not a factor during descents and remains in the Open position until you begin climbing uphill or pedaling. The idea is to have the fork and shock perform as they typically would when descending to take advantage of full travel for a plush ride experience. When climbing, the Open compression position is obtainable when impacts occur. For example, pedaling into a big rock or root will cause the fork or shock to change to Open. If additional impacts do not continue to occur after a few moments, Flight Attendant will revert to Pedal and then the Lock position. 

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The Pedal compression position is intended to provide the best balance of comfort and efficiency for improved traction and reduced suspension movement. A perfect example of when Flight Attendant remains in the Pedal position is when pedaling over small, repetitive bumps. However, we found that the system spent the least amount of time in Pedal, often changing to the Open position when impacts would occur and quickly switching straight to the Lock position if further impacts did not follow. The Lock compression position is the firmest compression setting and the most noticeable of the three positions. With basically no suspension movement, efficiency is maximized as power at the pedals is transformed directly into forward momentum. 

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Auto Mode set in Open Position
Override Mode set in Lock Position

Flight Attendant also features two additional modes for increased control and personalization: Manual Mode and Override Mode. Manual Mode gives riders the option to switch out of Auto Mode and cycle between the three compression positions at their command. Accessible only from the fork control module riders can then change between each position by engaging the assigned paddle of RockShox's new Left Hand 2 Button AXS Controller. This feature is nice for riders who want total control of the system, however during testing we never used Manual Mode as it seemed to defeat the purpose of having an automatic suspension lockout system. Override Mode gives riders the option to jump directly to their desired compression position by simply holding the assigned paddle of the Left Hand 2 Button Controller. One engaged, Flight Attendant will remain in the single compression position until the paddle is pressed again, returning the system to Auto Mode. Override Mode was one of our favorite and most used features during testing as we had it set to the Lock compression position. During undulating sections of trail, we would use Override Mode to keep Flight Attendant from opening compression on short descents or when coasting and pumping trail features. This allowed us to squeeze every bit of pedaling and rolling efficiency out of the trail to maintain a higher average speed. 

Bias Adjustment Feature

The most useful adjustment we consistently tinkered with while testing Flight Attendant was the bias adjust feature. Adjusted via the fork control module or through SRAM’s AXS App, bias adjust allows riders to fine-tune how Flight Attendant reacts in Auto Mode to best match personal preferences. There are five bias options to choose from that are referred to as -2, -1, zero, +1 and +2. The system comes factory set in the middle with zero bias. Adjusting Flight Attendant in the negative direction will cause the system to favor the Open compression position more often while adjusting Flight Attendant in the positive direction will cause the system to favor the Lock compression position more often. 

Adjusting the system bias can be done via the fork control module or the SRAM AXS App.

-2 System Bias
Zero System Bias
(+2) System Bias

When the system is biased towards Lock (+1 or +2), Flight Attendant favors the Pedal or Lock compression position as much as possible to provide a firm and efficient pedaling platform. When impacts do occur, the system will still change to Open but will jump back to Pedal or Lock at a faster rate. This is ideal for riders who prioritize efficiency and want the system to remain locked more often. When the system is biased towards Open (-1 or -2), Flight Attendant favors the Open compression position for a more plush and active suspension platform. The system will still change to the Pedal or Lock position but it will take a longer period of impact-free pedaling for this to occur. The Open rider bias settings are great for riders with technical or rough terrain who would benefit from additional traction or comfort. Regardless of which rider bias Flight Attendant is set in, it’s worth noting that Open, Pedal and Lock compression positions maintain the same compression tune as in Auto Mode. Adjusting rider bias only changes the system's tendency to lean more towards the Open or Lock position.

SRAM AXS App

Like with all AXS-enabled components, Flight Attendant can be customized and adjusted through the SRAM AXS App. Key features include configuring shifter paddle commands, adjusting low-speed compression for the fork and shock, setting rider bias, checking the battery life of each component, performing firmware updates and setting Override Mode preference. The App also provides helpful instruction on how to calibrate Flight Attendant before your first ride. Lastly, with plenty of colored lights indicating important information, the App includes a helpful key listing out what every color indicates in case you forget. We admittingly rode with our shock’s low-speed compression fully closed at first because we thought we were adjusting rider bias to +2.  

Rear shock low-speed compression adjustment
Fork low-speed compression adjustment
Controller Button Configuration
LED Color Indicators

Build Kits + Suspension Updates

For those itching at the bit to equip their current mountain bike with Flight Attendant, unfortunately, RockShox will not be selling the system as an aftermarket option. Well, at least for now. Instead, Flight Attendant will be coming stock on select top-of-the-line mountain bikes. As of right now, these bikes include the YT Capra, YT Jeffsy, Canyon Neuron, Canyon Spectral, Specialized Enduro and Trek Slash. RockShox of course plans to add more brands and models to this list. However, this will take time as they have to work in conjunction with manufacturers to make sure the shock motor module fits within a given frame design and then tune each of the three compression positions to best match each bike’s suspension kinematics. 

Specialized Enduro
Canyon Spectral
Canyon Neuron
Trek Slash
YT Capra
YT Jeffsy

Between the six bikes currently available, there are three fork models equipped with Flight Attendant: Pike Ultimate, Lyrik Ultimate and Zebb Ultimate. As if rolling out an entirely new automatic suspension system wasn’t already enough, RockShox is also introducing some major fork updates that are featured on all Flight Attendant forks. 

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Located at the bottom of both the damper and air spring are two rubber pucks that absorb high-frequency vibrations. RockShox refers to these pucks as Buttercups and they make a noticeable difference in reducing the transfer of small bump vibrations from the trail to the rider. The chassis of all three fork models now features pressure relief valves on the back of the lower legs which eliminates unwanted air pressure build-up in the lowers caused by changes in altitude or temperature. The Pike and Lyrik chassis also see changes to the lower legs and CSUs to drop the overall weight of the forks. Finally, all Flight Attendant forks feature new bolt-in hub cap adapters that allow riders to use standard hub cups if they do not have RockShox’s larger torque caps. The only shock equipped with Flight Attendant at this time is RockShox’s Super Deluxe Ultimate air shock. The shock features their all-new 3-position RCT3 Flight Attendant damper and is designed to handle the most aggressive descents and terrain.

On The Trail

Our journey with Flight Attendant began with a trip to Colorado Springs, Colorado where RockShox’s main facility is located. Over two days of action-packed riding we got to hang with the RockShox crew and gain insight into the process of developing Flight Attendant. Our first day riding with Flight Attendant was spent shuttled the Monarch Crest Trail outside of Poncha Springs. A historic Colorado trail with plenty of high-altitude pedaling, rocky descents and technical climbs, the term shuttle should be used lightly as we still climbed 2,600-feet over the 36-mile adventure. The ride was physically demanding but ultimately served as the perfect introduction to how Flight Attendant can transform the pedaling efficiency of a mountain bike.  Our second day of riding was spent sampling trails around RockShox’s facility where daily testing of Flight Attendant’s algorithm was conducted during development. With very few sustained descents or climbs, most of the trails we rode required occasional pedal strokes to maintain speed even on the descents. However, the rolling terrain allowed us to better understand when Flight Attendant becomes a factor and how the bias adjustment can be used to alter the characteristics of the system. 

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Once home from Colorado, all additional Flight Attendant testing took place on our local trails around Boise, Idaho. While the trails in Boise are not exceptionally demanding as they sweep across rolling hills, they did provide the perfect testing ground for Flight Attendant. When we aren’t riding test bikes, we usually ride 120-140mm trail bikes. We have found this amount of travel both compliments the amount of pedaling Boise trails require and allows us to still get rowdy on the descents. We tested Flight Attendant on Trek’s Slash enduro bike. With 160mm of rear-wheel travel and a 170mm Zeb Ultimate fork, the Slash was no questions asked, too much bike for our trails. However, as we will discuss below, the Slash turned out to be the perfect platform to see how Flight Attendant could transform its climbing capabilities.

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A New World Of Pedaling Performance

During the first few hours we spent aboard Flight Attendant, the crew from RockShox intentionally gave us minimal information about the system we were riding. They even covered the fork control module so that we could not see the LED lights pulsating as Flight Attendant changed between compression positions. The biggest takeaway from those initial miles on the system that has since become the standout characteristic of Flight Attendant is how insanely well it transformed our pedaling efficiency. 

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When grinding uphill and spinning away at the pedals, Flight Attendant is constantly making audible changes between its three compression positions to best match the terrain. However, the majority of the time the system remains in the Pedal or Lock compression position. In the Pedal position, the suspension feels very similar to flipping a pedal-assist switch on a typical rear shock. The suspension remains slightly active to soak up small bumps but there is an improvement in overall pedaling efficiency. Situations that caused Flight Attendant to change to the Pedal position were usually sections of trail with constant, small impacts. For example, a rough gravel road. In these situations, the impacts would be too small to cause Flight Attendant to shift to the Open position but significant enough to keep the Lock position from being acquired. Since most of the trails we tested on do not have constant impacts we spent the least amount of time in the Pedal position. Instead, we bounced between the Lock and Open compression positions.

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The Lock compression position almost completely limits suspension movement for a motionless, firm and superior pedaling platform. When riding in the Lock position, we were impressive at the speed we could carry uphill and how quickly we could lay down a few pedal strokes and power up any steep section of trail. It was in the Lock position that we had to keep reminding ourselves we were pedaling around a 160mm Trek Slash enduro bike. If we didn’t know better, the experience felt more similar to pedaling a mid-travel trail bike. Considering how dominate the Slash performed on descents and the factoring in how much its climbing capabilities were transformed with Flight Attendant, it’s almost shocking how well-rounded the bike became.

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The Open compression position was used more often than we expected on climbs when bigger compressions would occur. As an example, most of the climbs on the Monarch Crest Trail in Colorado had rock ledges or large roots mixed between sections of smooth, hardpack ground. As we pedaled into these features, any impacts that were large enough to either compress the fork or unsettle us in the saddle would cause the suspension to quickly move to the Open position. If the impact was less significant but still enough to warrant a compression adjustment, Flight Attendant would often set the fork in Open and the rear shock in Pedal. While Flight Attendant did use the Open compression position frequently during climbs, it was also quick to jump back to the Pedal or Lock position if no further impacts would occur. The only times we found ourselves remaining in the Open position for long periods was during the chunkiest of climbs or when the bias adjustment was set to the -2 position. 

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Overall, the feeling of Flight Attendant adjusting the suspension between its three compression positions is incredibly smooth and natural. As you pedal over bumps the transition time between each position is extremely quick. We never experienced the sensation of rolling over trail features with the suspension remaining too stiff. Since Flight Attendant is looking to maximize pedaling efficiency by reverting the system to the Lock position, the ride quality is firmer than what you would typically experience with non-electronic suspension. Of course, rider preference can be factored into Flight Attendant with the bias adjustment. Regardless, we enjoyed the firmer and more supported pedaling platform Flight Attendant provided as it changed our preconceived notions of how an enduro mountain bike can pedal. When applied to a mid-travel trail bike, we can only assume Flight Attendant would transform its pedaling capabilities to the level of a cross-country bike.

Descending Performance

Even though Flight Attendant does not affect the descending performance of the suspension, we have to praise how much fun we had riding Trek’s Slash enduro bike. The Slash is a purebred charger on the descents and provided incredible stability and control in the most demanding situations. Of course, part of that performance can be chalked up RockShox’s Super Deluxe Ultimate rear shock and the updates made to the Zebb Ultimate fork. The term ‘mid-stroke support’ is heavily diluted nowadays, but the ability of both suspension components to keep the Trek Slash riding high in its travel was outstanding. Perhaps the most supported suspension we have ridden in recent memory, we loved being able to dive into corners without blowing through travel. As for the changes made to the Zebb Ultimate fork, the standout feature was the new Butter Cup technology. When rolling at higher speeds over small, repetitive impacts that would not compress the fork more than a few millimeters, we experienced a lack of vibrations transmitted to our hands and arms.

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Fine-Tuning Flight Attendant To Match Personal Preferences

Throughout testing, we played the most with Flight Attendant’s bias adjust feature. What we loved so much about this feature was the ability to change how Flight Attendant reacted to trail impacts to match our personal riding preferences. We don’t find ourselves trying to emulate the same ride experience every time we hit the trails and the bias adjustment let us fine-tune Flight Attendant for each unique ride.

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Between the five bias settings, we rode the most in the -1 position. In this setting, Flight Attendant favors the Open compression position just a hair more than the stock, Zero bias. Based on our personal preferences, the Zero bias position provided too firm of a pedaling platform over most terrain. By riding in the -1 bias position, Flight Attendant would frequent the Open compression position more often which improved comfort and traction. On the other hand, we did ride in the +2 bias position on days where we wanted the most efficient pedaling platform across a wider range of trail impacts. In the +2 bias position, Flight Attendant rarely changed to the Open compression position when pedaling over bumps. This bias setting was ideal for pushing our limits on climbs as Flight Attendant remained in the Lock or Pedal positions the majority of the time. We also found that the system would revert back to the Lock position quicker after compression changes would occur. At the other end of the spectrum, the -2 bias position was never used during testing as it kept the suspension in the Open compression position too often. While this might be great for riders who have loose technical climbs and need to maximize traction or comfort, we noticed a huge loss in pedaling efficiency.

Downsides Of Flight Attendant 

We dug deep to find flaws with RockShox’s Flight Attendant system but honestly could not find any performance aspects of the system we would change or disliked. However, there are a few downsides to the system outside of how it functions hauling ass up the trail which are worth mentioning.  

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When Flight Attendant changes between its three compression positions, an LED light will pulsate on the fork control module indicating which position the system is in. Located within view while riding, the tendency is to constantly glance down and see which compression position is currently illuminated. After all, it’s an automatic suspension system and it better be making the most efficient decisions, right? We found that every time we rolled over a bump on a climb, our eyes would immediately shoot down to see if a compression change had been made. This of course can be distracting and dangerous when operating a mountain bike. The good news is that RockShox assumed many riders would have this problem and created Dark Mode. Dark Mode can be enabled via the SRAM AXS App and sets the LED lights to blink only once when a compression change is made before turning off. However, we would still bet most riders will have a hard time putting Flight Attendant in Dark Mode since the tendency is strong to always know what the system is doing. 

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If you’ve ever owned or ridden with somebody who has SRAM’s AXS drivetrain or a Reverb AXS dropper post mounted on their bike, then you are very familiar with the distinct noise of an AXS servo-motor. The relatively quiet, mechanical noise is made during every shift or raise of the dropper post and can be quite a nuisance once you chime into the sound. Well, with Flight Attendant, that tiny motor noise can be heard every time the fork or shock changes between a compression position. This is likely not an issue for most riders out there as the benefits Flight Attendant provides on the trail greatly outweighs a minuscule noise. But, its’ worth noting for riders looking for a silent, pure riding experience as Flight Attendant is a vocal system. The last downside we see with Flight Attendant is the fact that RockShox is not offering the system as an aftermarket option. We feel very fortunate to have spent time riding Flight Attendant but are disappointed we won’t be able to go buy the system for our personal bikes. We completely understand the complications that come with fitting Flight Attendant to each frame design, but offering the system on only expensive, top-of-the-line mountain bikes is going to limit who has access to Flight Attendant. 

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What's The Bottom Line?

RockShox’s new automatic suspension system Flight Attendant undeniably makes a massive impact on the climbing efficiency of your mountain bike. The system is intuitive and succeeds at anticipating the best suspension platform at any given moment to match both rider input and terrain impacts. RockShox did a fantastic job packaging Flight Attendant into small, wireless components that add minimal weight to your bike and are easy to install and set up. The mixture of on-the-bike adjustments via the fork control module as well as system customization via SRAM’s AXS App provides a variety of personalized fine-tuning opportunities. The only downside we see with Flight Attendant at this time is riders will only be able to enjoy RockShox’s newest technology if they purchase a complete bike that comes equipped with the system. But, we wouldn’t be surprised to see that change sometime down the road. 

For more information on RockShox's Flight Attendant system, head over to www.sram.com  

And for more insight into Flight Attendant from the team at RockShox who developed the system, give the video below a watch! 

 


About The Tester

Jason Schroeder - Age: 26 // Years Riding MTB: 15 // Height: 6' (182cm) // Weight: 168-pounds (76.2kg)

A once-upon-a-time World Cup downhill racer turned desk jockey, Jason has spent years within the bicycle industry from both sides of the tape. A fan of all day adventures in the saddle or flowing around a bowl at the skatepark, he doesn't discriminate from any form of two wheel riding. Originally a SoCal native now residing in Boise, Idaho, you can find Jason camped out in his van most weekends at any given trailhead in the greater Pacific NorthWest.

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