Next-gen FOX Live Valve semi-active suspension gathers real-time data from accelerating, braking, steering, and inertial sensors every few thousandths of a second. It then electronically adjusts compression and rebound damping in each of the four Live Valve shocks. Why is this special?
In some shocks there’s a dependency between compression and rebound adjustments. When the oil flows back and forth between the body and the reservoir, it moves through the same path. This means any adjustment to one technically affects the other.
Beyond being semi-active, what makes next-gen Live Valve shocks special are the unique oil flow paths for both compression and rebound. This means each adjustment is truly independent and does not affect the other. For example, in the same moment the system can increase compression while decreasing rebound to maintain better support, traction, and comfort.
Born from racing
The Live Valve TT project has received full support and focus of FOX's dedicated Motorsports Engineering and Tuning teams since its inception in 2019. FOX Racing Applications Development (RAD) and Factory Race Team drivers involved in the development process include Justin Lofton, Rob MacCachren, Cameron Steele, Andy McMillin, Bryce Menzies and Dan Fresh.
While initial development was started and continues to be developed on our own Geiser Bros 2WD platform RAD TT, Lofton was the first to utilize the new technology in racing on his 2WD Jimco-built race truck at the 2020 SCORE Baja 500. In his second race on Live Valve at the 2020 BITD Blue Water Desert Challenge, Lofton took the overall win. Since then, he has continued to race on and prove the technology on his AWD Mason Motorsports TT, including a win at the 2021 BITD Laughlin Desert Classic.
Fresh and Jeff Bader also ran Live Valve on their TT Spec class truck at the 2021 SCORE Baja 400 with our own Motorsports tuner Mike Kim in the navigator seat. By deploying the technology in a race vehicle in extreme racing conditions — along with our race tuner riding shotgun — we’re able to capture valuable real-world data that we can use to greatly accelerate development and tuning of the vastly complex electronic damping system.
To better understand the next generation of FOX Live Valve as it applies to TT spec desert-racing trucks, we spoke with Bryan Harrold, FOX Motorsports Program Manager.
What does Live Valve with independent semi-active compression and rebound mean for top-level FOX racers like Lofton and Menzies?
Bryan Harrold: Our main focus with this project was to minimize the tuning compromises often made in unlimited truck racing with 2-3 feet of suspension travel. While unlimited race trucks feature impressive off-road capability and performance over a variety of terrain, drivers historically have had to choose whether they want to set up the truck in favor of their own comfort or being able to absorb bigger hits and go faster through rougher terrain.
BH: With position-sensitive external bypass shocks, there is some ability to improve comfort by allowing the shock fluid to bypass the damping piston in the ride zone, while still protecting against harsh bottom outs in bigger events or topping out at full extension. The sacrifice with that direction is a lack of low-speed control, which equates to increased body roll. With three feet of travel, that effect can be very dramatic in cornering, braking, and acceleration.
By semi-actively controlling both compression and rebound, we’re able to minimize those tuning compromises between comfort and performance by using various sensor and driver inputs to optimize the amount of damping applied throughout the entirety of wheel travel. That means a driver should experience less fatigue in rough races by delivering a plush ride wherever possible while also allowing them to push harder by giving them support and protection when it’s needed most — without having to even think about it.
While a solid mechanical base tune is still crucial for optimal performance, Live Valve’s semi-active electronic damping will also change the game for tuning. The possibilities are truly endless and we’re able to provide a level of fine-tuning for any vehicle or driving style like never imagined through a variety of algorithms and tuning parameters that we can change on-the-fly without having to physically open a shock or turn an adjuster.
Walk us through the intricacies of this new technology.
BH: Independent control of both compression and rebound damping provides an unprecedented level of constantly variable, position-sensitive damping in both directions of wheel travel. While we’ve had the ability to control both compression and rebound damping on external bypass shocks previously, adding a Live Valve to each circuit allows the shock to adapt and adjust intelligently based on various sensor inputs.
"By semi-actively controlling both compression and rebound, we’re able to minimize those tuning compromises between comfort and performance by using various sensor and driver inputs to optimize the amount of damping applied throughout the entirety of wheel travel."
bryan harrold, fox motorsports program manager
BH: As it relates to vehicle dynamics, this separate control of compression and rebound damping allows us to compensate for things like body roll in cornering, mitigation of brake dive and acceleration squat, providing a controlled landing off jumps and critical support in g-outs.
For example, in braking we can tune our algorithms to increase compression damping in the front shocks and rebound damping in the rear shocks to slow down the inertial shift in weight to the front of the vehicle, minimizing brake dive and pushing in corners (understeer). That should help improve braking points as well.
Under hard acceleration, we can do the opposite to prevent the weight from transferring to the rear, giving a more balanced feel with a higher level of traction on the front tires, which is crucial for improved steering control and an added advantage for all-wheel drive vehicles.
BH: In cornering, we can take a similar approach by increasing compression damping on the outboard shocks and rebound on the inboard shocks to provide support on the outside tires and decreasing body roll as the weight of the vehicle shifts toward the outside of the corner, lowering the risk of rollovers.
For g-out scenarios, we can increase compression damping on all four corners to soak up the compression event and prevent a severe bottom out, then increase rebound damping to slow the shocks from rapidly extending, which will help prevents bucking or bouncing out-of-control – which could be further fine-tuned between front and rear.
In tight and twisty, smooth pavement sections or fire roads, we can increase both compression and rebound all around to provide sportscar-like handling. The list goes on and on.
What are the future benefits of Live Valve with adjustable compression and rebound on other FOX-equipped vehicles like UTV?
BH: Live Valve’s semi-active control of both compression and rebound damping will bring the same advantages our top racers gain to all vehicles and users – the ultimate optimization of comfort and confidence-inspiring performance for any terrain or driving style.
BH: We’re now at the point where we’ve developed a solid, race-proven foundation to build upon with the help of our racers, which will require them to re-wire their way of thinking and adapting to their vehicle’s previous limitations. With their direct input along with the array of data we are gathering, we aim to achieve all-new levels of suspension performance that can ultimately make anyone a better, more confident driver.
