Rock Shox Flight Attendant XC Suspension System Review

Rock Shox remains relentless, aiming to revolutionize the evolution of electronic suspension systems with their new Flight Attendant XC. Will they achieve a complete breakthrough this time?

The marketing for the Flight Attendant suspension system was on track right from the start. Nino Schurter clinched his historic 34th World Cup victory with the electronic assist, and at the Cross-Country World Championships in Glentress 2023, 5 riders from the top ten of the men’s elite were equipped with an electronic suspension system.

Nino Schurter, Victor Koretzky, Vlad Dascalu, Luca Schwarzbauer, and Luca Braidot tackled the battle for the rainbow jersey with Rock Shox’s latest Flight Attendant setup. Even the winner, Thomas Pidcock, had an electronic suspension system at Glentress, though it came from his sponsor SR Suntour, not Rock Shox. In terms of performance, things are going well, but why hasn’t an electronic suspension system ever gained widespread adoption in the market?

With the E:I Shock, the Fox Live Valve, and the Rock Shox Flight Attendant from the first generation, there have been several attempts at establishing electronics in suspension systems. But looking around on the trails, it’s apparent that none of these attempts have achieved widespread use.

The E:I Shock system was quite nice for a first attempt over 10 years ago. However, its performance was mediocre and the technology was prone to malfunctions.

The Fox Live Valve System was in a completely different league in terms of response times and functionality compared to the E:I Shock, but it was super expensive and very bulky. Sensors mounted on frames and fork castings had to be connected with wires to the monstrously clunky computer battery unit. Aesthetic no-go in a scene where chainring bolts are matched to the color accents of the jersey.

Two years ago, when Rock Shox introduced its Flight Attendant System for Enduro Bikes, the Americans managed to tackle the main weaknesses of its electronic predecessors. Yet, even the wireless system is relatively rare to see out on the trails.

One reason for this is undoubtedly the higher price of the suspension system compared to conventional setups. Another reason may lie in the initial focus of the first Flight Attendant, which was primarily aimed at downhill-oriented bikes with 160mm of travel or more.

No doubt about it: The Flight Attendant suspension system automatically locks out or firms up the suspension without any input required from the rider. This is similar to the old system. However, the Flight Attendant suspension has several brand new features especially for cross-country (XC) riders, which are largely software-based.

We delve into the nitty-gritty with all of our tests. With the abundance of facts and options that the Flight Attendant suspension system offers, we aim to provide a clearer picture with this quick bullet-point list. Fear not, each point will be thoroughly covered in the article.

Where there’s a lot of travel, an efficiency-boosting electronic suspension system has the biggest impact. That was likely the thought behind the first Flight Attendant for downhill-oriented bikes. And that may be true. But let’s be honest: How many riders regularly engage the lockout lever on their enduro bike’s standard shock?

It’s a minority. With a weight of 15 kilograms and tacky tires, even the most efficient suspension system doesn’t elevate the uphill performance of such bikes to a level that excites riders.

The situation is quite different for cross-country racers. The utilization of the previously mechanical lockout has already become second nature in this demographic. The automatic system solves a problem in the cross-country segment that previously had to be managed manually.

We’ve put the suspension system on the new Specialized S-Works Epic to the test. However, other manufacturers are also installing this new suspension system right out of the gate. The list below shows that this suspension system has convinced key manufacturers. It’s particularly intriguing to see that companies such as Orbea or Pivot, which traditionally spec Fox suspension setups, are now hitting the starting line with a Rock Shox product.

This presents a massive opportunity. Unlike electronic shifting or electronic dropper posts, the system operates entirely autonomously, without any input from the rider. This suspension works while you focus on the trail or the race.

The signs for the electronic breakthrough are better than ever before. However, to test the system, one must first get to grips with the setup and, most importantly, the vast array of customization options.

Before hitting the trails, it’s crucial to set up the suspension, meaning you have to adjust the air pressures and the rebound settings aside from the electronics at least once. Plus, all the electronic components on the bike need to be paired with the “Brain” in the fork and synced with the app. We’ve been working with the app in its prototype phase, yet the procedure was smooth even for those less tech-savvy.

During this setup process, it becomes apparent that if you have a SRAM AXS drivetrain, you can also pair the shifting to the system. For improved performance like never before, the system doesn’t just rely on acceleration and position sensors in the shock and fork but it also factors in the data about which gear you’re in and the current wattage at the pedals when deciding whether the suspension should be fully open, in platform mode, or locked out. SRAM skillfully utilizes its ecosystem here.

Once everything is paired, air pressures and rebound settings are dialed in, the sensors need to be calibrated once more while stationary. Rock Shox’s intuitive tutorial video ensures this process goes off without a hitch.

Through the accompanying app, there are numerous customization options. With the Bias Adjustment, you can tell the electronics whether the suspension should tend to close or remain in a more open mode.

Additionally, an “Override” button can be set up on the handlebar lever, which allows you to override the automatic system for any given time. When you press the button, the suspension remains open, completely closed, or in platform mode, depending on the configuration, until you press the button again.

This function is for those who don’t trust the electronics 100% and want to lock out the suspension or keep it fully open in particularly tricky situations, during a finish line sprint, or on a downhill section.

The engineers have thought of every conceivable aspect concerning the suspension, and they’ve designed the app so that you can truly tailor these variables to your individual needs. For example, you can set it up so that the fork will never lock out, but will shift into platform mode instead.

Admittedly, the plethora of options can be daunting at first, but you’ll get the hang of it quickly. High-tech demands its users to engage with the equipment. Ultimately, these are settings that you adjust once and then typically never touch again. Plus, the suspension still performs on the trail without the app and its tuning capabilities, and it even improves its function with each ride.

Rock Shox has developed a self-learning system that always uses data from the last 8 rides to categorize its performance into four sectors.

Depending on whether your current pedal force at the cranks is in the Sprint, High, Medium, or Low sector, the system operates differently. The basic idea is: the harder you pedal, the more likely the suspension will switch into the locked or platform mode, assuming that you prefer a firm suspension setup during a sprint. And the brilliant part is that these zones are automatically adjusted on an individual basis.

The suspension does not rely on standard settings that have to fit everyone from Nino Schurter to Average Joe but actually evaluates riding behavior individually. This is a brilliant move and showcases the superiority achievable with such an electronic system.

The differences in performance are indeed striking depending on the power output at the crankset and the bias setting. Ultimately, the acceptance of the system hinges not only on customizability but chiefly on its performance on the trail. How quickly does the suspension close and open, how accurate are its decisions, and how much trouble does it cause?

We didn’t just test the system on longer rides, but also in very specific situations to really put the technology through its paces. One thing became abundantly clear: The system works damn fast.

We deliberately provoked situations to check the response time. For instance, we went from a sprint on asphalt straight into a trail. During the sprint, the suspension was locked out. But the system opened up while we were still in the air.

The expectation was that you would feel at least a small jolt upon landing before the system opened up. That’s what you might be used to from Fox Live Valve or, especially, Specialized’s Brain forks, which have so far always tackled automatic lockout mechanically.

To our surprise, the system engaged mid-air and provided full comfort and control upon landing through the suspension without the need to overcome any initial stiction.

According to Rock Shox, during Nino Schurter’s 34th World Cup victory last year in Lenzerheide, the Flight Attendant suspension’s servo motor adjusted a staggering 1325 times over the course of a 90-minute race. That boils down to a suspension modification every 4 seconds. It’s evident: the system adjusts far more often than any human could possibly manage.

Even when the tires stick to the ground, the system responds lightning-fast. When you’re out of the saddle hammering on rough terrain, the suspension stays in its pedal platform mode. But just a few centimeters on flat terrain are enough to shift it into a more compliant mode.

Another scenario we orchestrated was transitioning straight from a descent into a sprint. This is a classic racing situation that occurs repeatedly on a looped course. Here too, the electronics prove their superiority: even before one hoists the seatpost via manual button, the suspension has already switched from open to pedal mode.

All this happens without any human intervention, but with the characteristic sound of the servo motor activating the compression damping adjustment. Thanks to swift reaction times, the system switches modes frequently, preparing the right suspension setting for every meter of trail, or rather, for every situation. This enhances efficiency over a manually controlled suspension that may be left locked out even on a bumpy meadow.

In comparison to the traditional mechanical lockout, the electronics have another ace up their sleeve. While with the remote lever of a race bike you can only lock out the entire suspension system, meaning both the shock and the fork, there are situations where the electronic suspension decides that the shock should switch to the pedal platform, but the fork should remain open.

This typically happens when you tell the system through the Bias setting that it should tend to lock out less. What surprises us a bit is that despite such features, the system cannot be used on hardtails. That’s because the system requires input from the shock for its complex calculations, which a hardtail doesn’t have. Maybe soon there will be a Hardtail sensor to do hardtail enthusiasts a solid.

During our test, the responsiveness and the choice of suspension mode on the trail truly impressed us. We were also incredibly eager to find out just how much the efficiency is boosted by the system compared to a mechanical lockout.

But that’s far more complex than one might think. Comparing lap times and wattage doesn’t cut it since the lockout also saves energy in the upper body’s stabilizing muscles.

There are a few attempts on YouTube where this clumsy comparison is drawn. However, technically speaking, it’s not substantiated. One would actually need to conduct the test with an ECG and spirometry (oxygen saturation) to get reliable data.

Rock Shox itself claims a 1.8% increase in racing efficiency. In a scene where some athletes still weigh their pasta to make race weight, that’s significant. Even half of this value would still be very appealing for racers. As to how credible the manufacturer’s study is at this point, we leave that up to the individual. We can only say that the suspension does exactly what you would expect from it, and it does it extremely well, but it certainly has its pain points.

In discussions about weight, the matter remains much more tangible than with efficiency. We’ve weighed every individual component and, crucially, compared them to their mechanical counterparts.

The system comes in at about 23 grams heavier than a mechanical Remote Lockout. However, it should be noted that in such cases, both systems are equipped with a power meter. Even compared to a system without a power meter and without a Remote Lockout, the electronic suspension only weighs an additional 310 grams.

The system operates on the familiar AXS batteries, which according to SRAM provide about 30 hours of power in the suspension system. In colder conditions, this may be slightly less, and on trails with fewer changes in terrain, it might last even longer.

We specifically asked SRAM if they were moving towards a self-charging system, but our inquiry was rebuffed. “That’s still a long way off.” The intermediate solution is the 4-port charger, designed to keep the AXS batteries for the drivetrain, dropper post, and suspension conveniently charged.

Of course, this high-tech gadget doesn’t come for free. In the past, bikes equipped with Flight Attendant were always €1,000 – €1,500 more expensive than comparable models without it. Now, for the first time, the system is available as an aftermarket upgrade. So if you already own a SID SL or SID fork, you can simply swap out the shock cartridge, pick up an additional shock and power meter, and get started. The price for the upgrade kit is expected to be under €2,000.

While the system is capable of a lot, it’s important not to overestimate it. Flight Attendant is not a telemetry system that allows you to analyze how much travel was used during various riding conditions.

It is completely separate from the air spring unit of the suspension components and does not provide setup tips, as you might be familiar with from ShockWiz. With all the adjustable options, it initially complicates the bike’s setup process. However, once it is dialed in, it relieves the rider of the setup stress.