Several brands have dabbled with active dampers, but have never fulfilled its promise. Now Fox has thrown its hat in the ring with Fox Live Valve.

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Fox Live Valve need to know

• Active suspension system adjusts compression damping in real-time
• Bump sensors operating 1,000 times per second
• Valve opens and closes in 3 milliseconds – 100 times faster than the blink of an eye
• Live Valve kit sold with fork and shock as upgrade package as well as standard fit on select new bikes

Live Valve detects bumps and adjusts the compression damping to suit the terrain in real time

Claimed weights

• Battery: 72g
• Controller and sensors: 104g
• Live Valve shock: 466g (185x55mm trunnion)
• Live Valve fork damper: 249g (36 fork, 160mm travel, 29in wheel)

Pricing (USD)

• Fox 32 fork $3,000
• Fox 34 fork $3,000
• Fox 34 Step Cast fork $3,125
• Fox 36 fork $3,250

Like it or not, electronics are coming to mountain biking. They’re already commonplace on road bikes, Shimano has been selling mtb Di2 for three years now, and in the near future we will undoubtedly see the floodgates open on a whole host of new electronically operated shifters, dropper posts and suspension parts. Whether they will transform our riding experience, or merely saddle us with greater weight, more complexity and yet more batteries to keep charged remains to be seen, and each new product will have to be judged on a case by case basis.

One thing we’ve long been excited about is the potential of active suspension systems. By that we mean a fork and/or shock that automatically adapts in real time to the terrain your wheels are riding over. By sensing bump inputs using accelerometers, it aims to be in the perfect mode for any given situation without needing any input from the rider.

How does it work?

Live Valve consists of a fork (using either the 32, 34 or 36 chassis), a shock (based on a Float X), two sensors, a battery and blackbox control unit with all the associated wiring needed to connect it all up.

The front sensor is neatly integrated into the fork brace and wired to the control unit

One sensor mounts to the fork brace, another attaches to the chainstay close to the rear axle, both feeding back any bump inputs to the down tube mounted processor. Wires then relay back to the damping circuits of both fork and shock.

While the cabling is relatively neat, there’s no getting away from the fact that the system adds clutter to the frame. So why not make it wireless? For the simple reason that the sensors sample at 1000hz (a thousand times a second), so wireless data transfer wouldn’t be able to keep up. You’d be mad not to rule this out as a potential area for development in the future though.

This solenoid is at the very heart of Live Valve

The really clever stuff happens inside the damping circuits. Previous active systems, such as Magura’s eLECT and Lapierre’s e.i., used servo motors to open and close damping ports, but they were slow and relatively power hungry. Instead Fox uses a solenoid valve, whereby an electric current changes the polarity of a magnet, causing a valve to open and close. The beauty of the design is that only a tiny amount of power is needed to operate the valve, and it only drains the battery when switching polarity.

With the valve open you’re effectively riding with the shock in the open setting. When it closes, it’s akin to running a pedal platform, which involves increasing the low-speed compression damping.

It’s also worth noting that you can manually alter the amount of compression damping in the open mode only with a 3mm hex key at the top of the fork leg and the shock.

How fast does it react?

The sensors attached to the frame and fork run at 1000hz. Which means bumps are being detected 1,000 times per second at the front and real wheel. If a bump is detected, the Live Valve opens within 3 milliseconds. That’s extremely quick – 100 times faster than the blink of an eye, in fact – and to all intents and purposes it feels instantaneous. But, fundamentally it’s still a reactive system, so it can only respond once it has hit a bump.

How does it ride?

This depends entirely on the situation. Firstly, a tilt sensor in the control unit decides if you are riding uphill, downhill or on the flat. It can also detect whether you are in freefall, as you would be off a jump or drop (and will open up accordingly).

Another wire connects to the fork’s damping circuit and operates the solenoid valve. A hex adjuster allows you to tune the level of compression damping when the system is fully open

Once the system decides what inclination you’re riding, it changes how much bump force is necessary to open the valve and the duration the valve opens for. For example, on downhills the valve stays open for longer than it does on climbs, whereas less bump force is required to open the valve on ascents than on flat terrain (to improve climbing traction).

These parameters are all factory set at present; only the Fox engineers and certain bicycle product managers have access to the software that lets you customise them. For example, flat terrain is set between +/- 6°. There are many, many ways to tune these values, so the danger of messing everything up is very high. Equally, the default tunes are regularly evolving, and may well change from bike to bike depending on intended use and the preference of the bike brand.

We tested Live Valve fitted to Scott’s World Cup-ready XC rig, the Spark RC, which was a slightly strange choice given that the Spark will not be available with Live Valve from launch – Scott is only fitting it to top end models of the longer travel Genius. Which raises question marks over whether this was the perfect platform on which to experience the system.

The control unit houses the processor and tilt sensor and is piggy-backed by the battery unit

Turn Live Valve on via the button on the battery and you can choose between five different levels of sensitivity. Level one is, according to Fox, a ‘car park’ setting that just lets people feel it working on a brief demo. On the other hand Five requires so much bump force to open that it’s really only for racing. That leaves 2-4 as the main usable settings.

We started in setting two and rode repeated laps of a familiar short loop consisting of a flat fireroad trail, a punchy climb and then a fast but gradual descent with a couple of pedally kicks along the way.

On the flat the suspension felt firm – as it would with the pedal platform engaged. Hitting small rounded bumps and stones seemed to be opening the valve – at least we could hear it opening and closing constantly, a bit like popping candy – but the behaviour of the bike didn’t change dramatically from the saddle. In fact quite the opposite – the transition between open and closed felt seamless. Was the bike more efficient, faster or was I using less energy as a result? Not while sitting down, but when I stood up and sprinted it was noticeable how much less effort was wasted.

Live Valve aims to put you in the optimum compression mode whatever the terrain

On the climb the suspension remained taut, but aim for a tree root and the system would open and the bump would be absorbed, just as advertised. When I hit the descent, though, the bike didn’t respond quite as predictably as I’d anticipated. It felt like I was getting deflected too much, and when I tried to preload the bike to unweight over roots, or pump for speed through compressions, it didn’t respond predictably and didn’t push back as I would expect. Instead it seemed like I was being met with a wall of resistance as opposed to a spring that builds resistance progressively.

The next lap took it up a notch to level 3. This was much firmer and notably racier, with the system more reluctant to open up the suspension. The bias had definitely tipped in favour of efficiency rather than comfort or traction. As such it was harder to go fast on the descent, but I didn’t feel like I was gaining speed or saving energy saving elsewhere while I was spinning along in the saddle.

Our Scott Spark RC test bike equipped with Live Valve

For a final run I turned the whole system off. On the flat fireroad there was slightly more movement from the suspension when in the saddle, and noticeably more when I stood up and rocked the bike from side to side. Seeing as the stock Spark RC is pretty efficient anyway, the bobbing was far from excessive. And on the flowing singletrack and downhill section the bike now reacted in a completely natural and predictable way. If you load and unload your bike’s suspension to gain speed and smooth out the terrain, you’ll know what I’m talking about. As such I was more accurate with my lines, carried more speed and generally felt more in control and adopted a more relaxed style than I had been on previous runs. Further rides, on more rougher, more technical trails amplified the feelings I had on that initial ride.

Second opinion

For balance I reigned in a second opinion from our in-house XC racer, James Bracey. While I was riding a race bike like a trail bike, James slapped on his clipless pedals and sprinted off on fast-paced rides that emulated an XC race as much as possible. Here’s what he had to say:

“Coming from a cross country racing background, the idea of a system that can act as an automatic shock adjuster is one that really appeals. No more fiddling with handlebar levers or awkward twiddling of shocks when you really should be concentrating on the task in hand is a. good. thing. And as such Live Valve fulfils its remit well. Functionality is unquestionable, but is more obvious at speed and when climbing out of the saddle, when the popping of the system becomes noticeable as it flicks on and off rapidly. At more leisurely paces it becomes harder to distinguish whether the system is working, and it is here that I was more inclined to question and mess about with the settings. My main issue with the system as it stands (and this is purely from a personal/racing opinion) is that Live Valve adds weight compared to a ‘normal’ suspension set up. For XC racers increased weight is still pretty much a no-no. For normal trail applications it’s difficult to see many riders wanting to invest a huge chunk of cash on a technology that adds a relatively minor boost in performance.”

What about battery life?

It’s impossible to be specific as this will vary according to terrain, settings and temperature, but Fox claims an average of 15-20 hours ride time. A full charge via the mini-USB input takes under two hours and can be done with the battery on or off the bike. Just fifteen minutes charging will give enough juice for a two hour ride, and should you run out of battery, you can ride the bike with the system off.

The battery should last at least 15 hours and is removable for charging and sealed from the elements

What bikes will it be sold with?

At the moment, Live Valve will only come stock on high-end models from Pivot, Scott and Giant, while Rocky Mountain will also have Live Valve compatible frames. You can buy the system aftermarket and run it on your own bike, but with a starting price of $3,000 USD (for a Fox 32 fork, shock, control unit, battery and wiring) it is at the very top end of the premium market. Expect Live Valve equipped models to command a premium of around $1,800 over their passively damped equivalents.

So who’s it aimed at?

Affluent people, that’s for sure, but Fox does not single out one particular riding segment as being its target market. On the one hand it talks about being an advantage to XC racers in the Live Valve press info. Later on it quotes EWS racer Greg Callahan, who managed to snip a couple of seconds off his best time using Live Valve on a certain track during testing– no mention is made of what type of track it was or how long it was. And then we have the fact that Scott and Pivot are only fitting the system to their trail bikes – not their XC or enduro models.

However, in our opinion we can see it offering benefits to those riders that regularly use their pedal platforms, and like the feeling of a bike that doesn’t bob on smooth trails or climbs, but who don’t want to have to remember to open up their forks and shocks again when it gets rough.

Riders with a relatively passive riding style at speed, or when descending, that let their bikes do the lion’s share of the work may prefer being able to focus on their riding and not what their suspension is doing. That’s not meant to be a defamatory comment; those riders exist, and they may well profit from the system. E-bikes are another potential benefactor, where the additional weight and complexity will sit more happily alongside all the other technology, and where the bikes are fundamentally harder to ride dynamically.