We've seen a few active suspension systems fitted to mountain bikes over the years, but none as sophisticated as RockShox's new Flight Attendant. With wireless connectivity and a suite of high-tech sensors, this predictive suspension control aims to put your bike in the perfect mode for every inch of trail.
We’ve spent around 20 hours on the new RockShox Flight Attendant predictive suspension system. Here’s our first ride review of this sophisticated new tech that’s sure to be on some of 2022’s best mountain bikes.
RockShox Flight Attendant need to know
- Active suspension system automatically adjusts compression damping to maximise efficiency without compromising bump performance.
- Suite of sensors constantly monitors parameters such as bike angle and acceleration, suspension movement and crank rotation. This data is processed by the control module mounted to the fork and run through an algorithm to decide the optimum damping mode.
- Both fork and shock can run in Open, Pedal or Lock mode, and the system can mix-and-match modes front and rear depending on the situation.
- Ability to fine-tune the system bias and take full manual control.
- System always has a bias to the open mode.
- Currently only available on certain complete trail bikes and enduro bikes.
F1-winning tech – until it was banned…
Back in 1992, the Williams F1 team designed a race car that completely dominated the season, winning nine races along with the Drivers’ and Constructors’ World Championships. It was so far ahead of the competition that it was up to two seconds a lap quicker on certain circuits, in a sport that measures most gaps in tenths of a second. The reason for that success was active suspension, and it made the cars so fast it was banned the following year.
While still absent from F1, many road cars use sophisticated active suspension systems to improve comfort without compromising road holding, and over the years a few mountain bike brands have trialled the technology. Magura’s eLect and Lapierre’s e.i. designs never really gained traction, but more recently Fox released its flagship Live Valve design – a product that we tested a couple of years ago and is still available on a small selection of complete bikes. Judging by the prototype parts being tested by Myriam Nicole and Greg Minnaar on the World Cup DH circuit, it’s very much still a work in progress too.
Now there’s a new kid on the block, it’s called RockShox Flight Attendant and it’s the most sophisticated system ever produced for mountain biking. But is that enough to make it succeed where other systems have fallen by the wayside?
RockShox Flight Attendant Vs Fox Live Valve
Before delving into the nitty gritty of Flight Attendant, it’s important to understand three key advantages it possesses over other systems. Firstly it always defaults to the Open position. With Fox’s Live Valve, the system defaults to the closed (locked) position and only opens up following feedback from a sensor. Secondly it’s a predictive system rather than a reactive system, so by monitoring parameters aside from just bike angle and bump input, it should detect a situation where it needs to open up before you actually hit a bump. And lastly, it’s completely wireless, so while it adds weight, and there are a few additional parts, there’s minimal additional clutter.
Equally crucial to the understanding of Flight Attendant is knowing the ultimate goal of the system. In essence, it wants to ensure that your bike’s compression damping is in the optimum mode for any given situation on the trail. To do that it aims to provide maximum efficiency when pedalling without affecting bump performance where traction/grip is paramount.
Most of us already have some kind of pedal platform on our bikes, but being manually activated, they tend to be under-used. Partly because it’s not always easy to take a hand off the bar and reach for a lever, and partly because we worry about forgetting to open it up again before dropping into a descent.
So what if you didn’t need to reach down and flick a lever to switch on a lockout? What if you didn’t need to press a button or push a lever on a remote to make your bike more efficient? What if you didn’t even need to think about the best setting for your suspension because it was already in it? That’s what Flight Attendant aims to do; be in the best setting for every inch of trail, so that you used less energy on every little rise, out-of-the-saddle sprint and undulating climb yet still extract the maximum suspension performance from your bike on every descent, or fast, flowing stretch of singletrack.
The system comprises three main elements: The control module mounted to the fork’s damper leg (Pike, Lyrik and Zeb all have new Flight Attendant variations): a motor module attached to the rear shock (Super Deluxe Ultimate): and the pedal sensor, that sits inside the BB axle of either XX1 or X01 level cranks. There’s also a left hand SRAM AXS paddle shifter that can be used to choose between manual and auto modes without taking your hands off the bars, although you can get away without it. At the moment the system will only be available on selected models from Trek, Specialized, YT and Canyon although other brands will follow. Currently you can’t buy Flight Attendant aftermarket, although that may change in the future.
How does it work?
Flight Attendant uses an array of sensors to monitor what is happening to the bike (and rider) and adjust the compression damping accordingly. Think of it as a vast and complex flow chart where there are many different paths to five possible outcomes (the fork will never be firmer than the shock). Each individual component has an accelerometer and a gyro gathering data. This data is collected and fed back wirelessly to the control module mounted to the fork. Depending on the information it receives, the control module will decide whether the fork and shock need to be in the Open, Pedal or Lock modes, or a combination of these front and rear. It’s worth noting that Lock is not a full lockout but rather a very firm compression damping setting.
How fast does it react?
According to RockShox, the sensors operate at 200hz, that’s 200 decisions per second. RockShox says that the ultimate speed of the system was less of a critical goal than making sure the correct decisions were made at the appropriate time. Certainly, during testing I was never concerned about reaction times at either the fork or the shock.
Does it learn as I ride?
No, there is no machine learning, or AI, going on with Flight Attendant, however, RockShox continues to collect data from its test riders about how the system is used and the situations they encounter, so the algorithm will continue to be refined and improved and updates will be available to consumers as and when they are made.
Can I still take control?
Yes, simply by hitting the left-hand AXS paddle you can assume manual control of the dampers and decide which setting you want them in. It has to be said though, while I’m a bit of a control freak, not once have I felt the need to take over the reins from the Flight Attendant.
How much does it weigh?
We weighed the Zeb on our Trek Slash test bike at 2,450g (170g heavier) and the shock at 628g (around 120g heavier), while the crank sensor weighs 37g, so the system adds around 300g extra (taking into account the extra weight of the Zeb’s bleed valves and new internals).
How long do the batteries last?
Depending on temperature, terrain and riding style, the fork battery should last a claimed 20-30 hours, the shock battery 30-40 hours and the pedal sensor and control unit batteries around 200 hours. Both the fork and shock unit use standard AXS rechargeable batteries as found on the Reverb and rear derailleur.
What happens if the batteries run out?
The system will automatically go into open mode if it detects a battery about to go flat.
New fork platforms
Flight Attendant is bolted to three brand new fork chassis, all getting Zeb-style angular crowns and braces. The Pike Ultimate Flight Attendant still runs 35mm upper tubes with 120mm, 130mm and 140mm travel options for both 27.5in and 29in wheels. Moving up the range, the Lyrik Ultimate Flight Attendant also retains its 35mm upper tubes with travel options at 140mm, 150mm and 160mm. Both wheel size options are available. Finally there’s the Zeb Ultimate Flight Attendant with 38mm upper tubes and travel from 150mm to 190mm in 10mm increments. All three forks get new Debonair + air springs (designed to give a softer initial touch) and Stiffness Reducer adaptors, to help you align your front wheel if you choose not to run oversize Torque Cap end caps. Again, both wheel size options are available. But the revisions go more than skin deep on all three forks…
At the base of each leg, the damper rod and air spring piston attach to the lower legs using new foot nut ‘pucks’. These gold mounts incorporate internal rubber bumpers that claim to take out 20% of unwanted trail buzz and help to reduce hand and arm fatigue.
Pressure Relief Valves
Not to be outdone by Fox, all three Flight Attendant forks get bleed valves on the back of the lower legs to release unwanted pressure build-up due to changes in altitude or temperature over the course of a descent or a ride. Just press the dimples to release any trapped air between the upper and lower tubes.
What bikes will I be able to buy it on?
To begin with, RockShox has kept the list of Flight Attendant bikes as exclusive as your average VIP private jet. In addition to the Trek Slash 9.9 I’m riding here, there will be a Canyon Spectral and Neuron, Specialized S-Works Enduro and YT Jeffsy and Capra. Of course, throw in the current pandemic and all the supply issues that entails and it’s probably a wise choice. So for the time being, getting your hands on Flight Attendant might be quite tricky, but with more brands due to join the passenger list further down the line, availability won’t be restricted forever.
How it rides
Obviously Flight Attendant is not something you can currently bolt on to your existing bike, so it made sense for RockShox to supply it on one of the models available at launch. However, supply issues on various components meant it could only source a frame (in this case a Trek Slash) and build it using SRAM’s suite of components. Hence my test bike does not have the same spec as the production Trek Slash 9.9 and you’ll have to treat this as first ride impressions on Flight Attendant itself rather than the Slash you’ll actually be able to buy.
The first question that needs to be addressed is how does it stack up against Fox’s Live Valve? Having ridden both systems, my opinion is that Flight Attendant is far better suited to the type of riding I enjoy, specifically fast singletrack, technical descents, jumps and features. Basically anything with a downhill bias. When I tested Live Valve, I preferred the bike’s response when the system was turned off on the descents (currently not something you can do easily on-the-fly). Riding Flight Attendant, however, in 150km and 14 hours on a wide variety of terrain, not once did I feel the need to either switch it off or override the computer. Throw in the wireless aspect and the ability to tune settings with the app and it’s an easy win for Flight Attendant.
The key to its success is its readiness to open up the damping, so when you need your suspension, it’s always there. That’s down to feedback from the sensors being correctly interpreted by the algorithm and predicting when those situations arise, reading the signs you give off through the bike as you approach a bump or feature. Even when you remain completely static and pedalling, say on a gradual climb, as soon as the fork hits a modest bump everything opens up. Get out of the saddle to pedal and put weight over the front end and the system stays in Pedal or Lock. but lift the front wheel and tap it back down on the trail and it opens up. It’s that sensitive.
Adjusting the system bias makes a noticeable difference to the response. Go to the firmer side of the scale and Flight Attendant goes into Lock much earlier and stays in it longer, needing more signals to open up. It’s an ultra efficient mode that will better suit the more XC-side of riding, but for me the -1 bias to open worked best, improving the efficiency of an enduro bike without losing its sense of capability and composure.
Where Flight Attendant’s advantages can most be felt are on undulating trails where you wouldn’t necessarily bother to reach down and flick a lockout lever. In these situations you always get the most direct power transfer possible, meaning the bike never bobs up and down, soaking up your precious energy. Get out of the saddle to power up a rise or sprint along a flat section to top up your speed, and the whole bike will tense up and respond immediately. I can see it being a fantastic ally for enduro racers (and potentially DH racers) where sprints and climbs can be crucial to a good overall result, but making adjustments on-the-fly is difficult. Shooting photos of this bike, it was also immediately noticeable how much quicker it got up to speed when sprinting into a corner “just one more time”, although I appreciate this isn’t something that will win over many riders!
Because the bike sits higher in its travel, ground clearance is also improved. Which means fewer pedal strikes as well as making it easier to time your power stroke to avoid rocks and roots on challenging climbs. You do feel a bit perched though, and when you do need to dab or even jump off when a crux move goes wrong, the ground is further away.
As an energy saving technology, Flight Attendant certainly works. It always ensures your bike is in the most efficient setting when you want all your energy going into the drivetrain, but feels exactly like a regular bike when you want comfort and grip. It works seamlessly in the background so that you can just let it do its thing and never worry that it’s going to do something weird or quirky. Like a good waiter, it always seems to anticipate your needs while blending into the background when you just want to enjoy the experience. And RockShox has done an impressive job of integrating all the hardware into the bike so that it adds minimal weight and bulk. On the flip side, it does add weight, it does add complication, there’s more to go wrong, more batteries to charge, and last but not least, it adds cost. And the gains, while appreciable, are not life-changing. Like first-class travel, it’s a luxury rather than a necessity, but given the chance, who wouldn’t want to be one of the lucky ones that gets to turn left.