Rockshox Flight Attendant XC: Smart & fast? - MTB suspension of the future learns with you!

The first contact with the new Rockshox Flight Attendant suspension is a mixture of curiosity and scepticism. Even at the presentation of the first version of the electronic suspension (at that time for long-stroke enduro bikes), you could feel a bit like you were in the film Transformers. Nobody believed that the blinking suspension fork would turn into a robot alien on the trail. Nevertheless, the promises made by Rockshox seem like something out of a science fiction blockbuster. Thanks to a smart algorithm, the suspension is supposed to learn from the rider and provide them with the perfect setup at lightning speed and fully automatically. The "flight attendant", as Flight Attendant can be translated, aims to achieve the perfect symbiosis between man and machine. We have all the information on the futuristic cross-country suspension and have already been able to test the new Rockshox Flight Attendant system.

Rockshox Flight Attendant 2024: Electric suspension for XC bikes

In the Cross-Country World Cup last year, the pros were often seen riding around with mysterious black boxes on their suspension elements. When Nino Schurter clinched his 34th World Cup victory in Lenzerheide and thus immortalised himself in the history books of MTB sport, his suspension was automatically controlled by the Flight Attendant system. During the 90 minutes or so of this race, the electric unit made 1325 adjustments to the fork and shock. Would Schurter have completed his record-breaking ride without the electric suspension? Probably. According to Rockshox's own tests, the new technology provides an average time advantage of 1.8 per cent in race situations. That may not sound like much, but in a 90-minute race it could mean an advantage of up to 96 seconds. But what exactly does the electronics do to the suspension elements?

The Flight Attendant System is based on the Rockshox SID Ultimate suspension fork and the Rockshox SID Luxe shock. It aims to give the rider the best possible suspension setting in every situation. In other words, for moments when a cross-country racer needs propulsion, this means utilising the energy as efficiently as possible to accelerate the bike and releasing more reserves in moments when tiring impacts and vibrations need to be kept away from the body. XC bikers normally use mechanical solutions to adjust the compression damping on the fly using a lever or twist grip.

On the Flight Attendant landing gear, small electric motors on the forks and dampers can take over this task independently, without the pilot having to do anything and in real time. In automatic mode, the system makes a decision about the position of the landing gear every five milliseconds. This is around 80 times faster than the duration of a human blink. This allows the driver to concentrate fully on the racing action without having to worry about the correct setting of the suspension elements. Rockshox has developed the underlying algorithm over the last few years based on thousands of hours of data analyses and rider input.

Computer technology on the cross-country bike: how Flight Attendant works

Already from the previous Rockshox Flight Attendant suspension was known to collect a lot of data about the movement of the bike on the trail. Thanks to the integration into the Sram AXS ecosystem, the new system is now fed with even more data via radio. The suspension can now also communicate with the corresponding AXS derailleurs and powermeters. A clever move by Rockshox: the electronic suspension system requires parts from the Sram component portfolio to function.

Flight Attendant makes the automatic settings in three stages on the Rockshox SID suspension fork and shock. The three-stage Charger Race Day 2 damping is used in the suspension elements. Similar to the already known 3P compression adjustment of the "analogue" Rockshox SID componentsthree modes are available. In Lock mode, the suspension is locked and does not allow any energy to be wasted during sprints with high rider input. In Pedal mode, the compression damping opens partially to create a little more traction and comfort. In Open mode, the damping is opened to absorb larger impacts.

Unlike cable-controlled suspension, Flight Attendant can influence the fork and shock settings separately thanks to a function called "split states". If the system decides that a different setting is suitable for the front and rear of the bike, it switches the fork and damper to different modes. The damper is always one step firmer than the fork.

Flight Attendant smart landing gear: the machine learns, the human retains the upper hand

As with a "normal" lockout, racers can assign the "override function" to a button on their AXS controller to switch between the three modes. The difference: everything runs wirelessly. With this manual control, the pilot can intervene in the action at any time, even when the algorithm-controlled function is active. The second option for switching between modes is automatic. Flight Attendant automatically switches between Open, Pedal and Lock. Coloured LEDs on the right fork crown indicate which mode is currently active.

However, the smart automatic system does not always behave in the same way. With the help of the "bias adjust function", the setting behaviour can be influenced to better suit personal preferences or a specific route. Bias-Adjust can be adjusted from minus two to neutral to plus two in five steps. In the negative setups, Flight Attendant uses Open mode more frequently, while in the positive presets the system often resorts to Lock mode. If desired, however, the automatic system can also omit Lock mode completely and then switch to Split mode more frequently. This can be set in the Sram AXS app.

One of the core competences of the new Rockshox Flight Attendant suspension is its ability to learn. Although there is no artificial intelligence in the classic sense behind the control system, there is a smart algorithm. With its help, the system aims to get to know the racer's behaviour in order to adapt the settings to their current needs. Rockshox calls this technology "Adaptive Ride Dynamics". The system uses data collected from previous rides to calculate personal performance zones. Riders who ride a lot at race pace are therefore assessed differently by the algorithm than riders who take a more leisurely approach. Flight Attendant uses the link to the Quarq power meter to determine an individual performance level. Riders who spend a lot of time working with wattage can also personalise the threshold values of the power zones in the Sram AXS app.

In the low performance zone, which Rockshox provides primarily for regeneration phases, Adaptive Ride Dynamics tends towards a comfortable suspension setting with an increasingly open mode. In other words, the automatic system leaves the suspension elements fully open more often and for longer. In the middle performance zone, the system is designed to create a balance between comfort and efficiency in order to adapt flexibly to different terrains. The suspension makes a more efficiency-orientated setting in the high performance zone. The fork and damper are then set increasingly firm to cope with high-speed laps or steep climbs. In the highest level, the "sprint zone", the algorithm encourages the fork and damper to go into lock mode more often and prioritise efficiency over everything else.

The more a bike with Flight Attendant suspension is ridden, the more the system gets to know its performance. It develops its full "intelligence" after at least seven rides of 45 minutes each. This means that most riders should have collected a decent database after around a month. If an individual ride falls completely off the grid because the performance was noticeably low or the lap was too short, it is not taken into account by the algorithm. If another rider gets on the bike with personalised suspension, Adaptive Ride Dynamics can also be switched off temporarily. Of course, personalisation can also be reset completely.

How the intelligent suspension rides: Rockshox Flight Attendant on test

The Specialized S-Works Epic 8 is the world's first bike to be equipped with a superlative race fully. The 14,500 euro technical wonder carries nine batteries and claims to be the fastest 120 millimetre MTB in the world. Is that true? We have already been able to test the new Rockshox Flight Attendant suspension extensively on the brand new Specialized S-Works Epic 2024.

Rockshox Flight Attendant: models, prices & weights

To be able to use all Flight Attendant functions, you need at least a fork and damper as well as a cadence sensor or power meter from the AXS series. Both shaft and spider-based Quarq power meters are compatible. The latter costs around 540 euros in the Eagle version without chainring and crank, for example. The Adaptive Ride Dynamics automatic system becomes more precise when other AXS parts are also activated. Without a power meter, the algorithm does not come into play and the behaviour of the automatic system can only be influenced via the bias settings. The electronic Flight Attendant parts add just under 130 grams to the fork and 100 grams to the shock compared to the conventional SID Ultimate Parts.

Suspension fork: Rockshox SID Ultimate Flight Attendant

• Suspension travel: 120 mm
• Weight: 1624 g (manufacturer's specification), on our test bike we measured 1606 g with shortened stem
• Price: 1599 Euro

Suspension fork: Rockshox SID SL Ultimate Flight Attendant

• Suspension travel: 100 / 110 mm
• Weight: 1480 g (manufacturer's specification)
• Price: 1499 Euro

Shock: Rockshox SIDLuxe Ultimate Flight Attendant

• Weight: 349 g (manufacturer's specification), on our test bike we measured 366 g
• Price: 949 Euro

The futuristic technology package is presented for the first time on the new Specialized Epic. There, however, it is reserved for the sinfully expensive S-Works top model. Other complete bikes are to follow. Unfortunately, the smart suspension will remain expensive for the time being. However, with the right amount of money, Flight Attendant can also be retrofitted to your own bike. The corresponding upgrade kits will be available from 13 June 2024.

Models that are theoretically compatible include Canyon Lux Trail and Lux Worldcup (both 2023+), Mondraker F-Podium (2023+), Orbea Oiz and Oiz TR (2020-2023), Pivot Mach 4 SL V3 (2023+), Santa Cruz Blur and Blur TR (both 2023+) and Specialized Epic Evo (2020-2023). A detailed list of compatible specs can be found on the Rockshox website.

The new Flight Attendant system is currently only aimed at marathon and cross-country full-suspension bikes; the technology does not currently work on hardtails. Adaptive Ride Dynamics is not currently available for e-MTBs. However, all Flight Attendant suspension elements are compatible with each other. This means that a SID Luxe rear shock could be combined with a Pike fork from the Flight Attendant range on a bike with 120 millimetres of rear travel and 130 millimetres at the front.

Existing Rockshox SID and SID SL from model year 2024 can be converted using the model-specific Flight Attendant Control Module and the Flight Attendant Charger Race Day 2 damping. Conventional SID Luxe shocks cannot be converted to Flight Attendant due to the missing attachment for the motor module.

In terms of software, the Flight Attendant project remains exciting. In the future, there could always be new functions for bikes with Flight Attendant through various firmware updates, such as the integration of the TireWiz sensors.

Up to nine batteries on the MTB: electrification is progressing

As the fork and shock of the Rockshox Flight Attendant System communicate via radio and are controlled using electrical energy, they each need their own AXS battery. On average, the fork battery should last for 20 to 30 riding hours, while the shock should last for 30 to 40 riding hours. A battery is fully charged in around one hour. This is the same energy storage system that is also used in Sram AXS derailleurs and the Rockshox Reverb AXS dropper post. The Quarq Powermeter contains a button cell battery. Like the alternative AAA batteries in the pedalling sensor, this should provide power for around 200 hours. At 400 hours, the batteries in the wave-based power meters last the longest. There is another button cell in each of the two AXS pod controllers. They should also last 200 operating hours each.

In the case of the Specialized S-Works Epic, two additional button cells are used in the TireWiz air pressure sensors of the tubeless valves. In total, nine individual energy sources come together in this setup. After all, the AXS batteries can be interchanged as required. The charge status of the individual parts can be checked in the Sram AXS app. If one of the batteries runs flat, Flight Attendant opens the compression stage completely and only returns to automatic mode once a charged battery has been inserted.

All electronic parts of the system are waterproof in accordance with the IPX7 standard, which also applies to road vehicles, for example, even against short-term submersion. The vapour emitter remains off limits! The optimum operating temperature for AXS batteries is between zero and 38 degrees. Rockshox advises against use below minus twelve or above plus 49 degrees.