When Ford unveiled its 2021 F-150 Raptor earlier this month, it famous such upgrades as revised 5-link rear suspension, the usage of new Fox 3.1 Dwell Valve shock absorbers, and the supply of 37-inch tires, every employed to boost the pickup truck’s already legendary off-road capabilities.

Fox Manufacturing unit adopted up with particulars about its new 3.1 Dwell Valve shocks “combining the most effective of semi-active, electronically-controlled compression damping with desert race-winning, position-sensitive inside bypass expertise to supply a easy and comfy feeling on the pavement with aggressive management and stability at excessive speeds off-road in actual time.”

Fox additionally provides the inner bypass coil-over entrance shocks for the brand new Raptor. 

Justin Lofton just lately posted the Dwell Valve’s first Limitless class off-road racing victory, driving a Trophy Truck to victory in The Desert BlueWater race in Parker, Arizona. The racing crew had been working for 18 months with Fox to develop the brand new shocks, however the historical past of the expertise goes again a lot additional, the corporate notes. 

Fox created a three-person superior growth crew in 2011. Everet Ericksen was amongst these three individuals — one other hand a PhD in magnetorheological fluids — and is credited with the event of the Dwell Valve.


In a information launch, Ericksen notes that the undertaking began with the so-called Simon valve developed for Cannondale bicycles utilizing MR fluid expertise. A few yr later, Ericksen realized the undertaking was not succeeding and began over.

In 1999, he was working for Tenneco Automotive, a Detroit-based automotive provider, the place he developed an digital suspension for the Audi A6, solely to have that undertaking scrapped after 9/11.

“I feel the idea of Dwell Valve was noodling in my mind since then after which collided with the unstable ‘Simon valve’ resurrection undertaking and the power-hungry MR fluid undertaking…” Ericksen stated.

In 2012, Erickson had the Dwell Valve practically prepared. Nevertheless, “There was one a part of it that I couldn’t resolve, so I took the design to Bob Fox and we labored on it collectively for a few month. He prompt one small element that took it from not working to working. It was a terrific second! Bob and I are each on the unique patent.”


The brand new expertise first was used in a bicycle utility, Erickson added. Working with Bosch on software program and electronics enabled the expertise to be utilized to full-size 4-wheel automobiles, Trophy Truck racing and now to the brand new F-150 Raptor.

Fox not solely was a motocross racer, however a physicist who began growing his personal suspension designs in 1974 and in 1978 launched the Fox Manufacturing unit.

“Dancing the nice line between on-road consolation and off-road efficiency is one thing Fox does greatest,” famous Tony Pauly, Fox group director of selling, “and we really feel the brand new 3.1 Dwell Valve delivers on our promise to Ford to raise the 2021 F-150 Raptor.”

In response to the Fox information launch, the “patented position-sensitive inside bypass damping mixed with Dwell Valve digital expertise repeatedly and intelligently adjusts compression damping in real-time, delivering the optimum trip for any terrain or driving state of affairs. Through the use of automobile sensors and accelerometers, Dwell Valve can immediately adapt to inertial, steering, braking, and acceleration inputs to actively maximize dealing with, consolation, and bottom-out resistance.”

The shocks are lined underneath the Raptor’s 10-year/150,000-mile guarantee.

“Fox elevated the shock our bodies and internals from the earlier design, permitting you to drive full tilt off-road with elevated dealing with efficiency whereas considerably bettering management over larger obstacles. With a dynamic vary of twice the prior valve design, the brand new digital valve structure shrugs off considerably bigger hits with the sensation of bottomless journey and smooths out probably the most rutted out teeth-rattling washboards.”

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In comparison with the earlier model used on the 2020 Raptor, Fox stated the brand new Dwell Valve affords double the vary of damping management of MY20 Dwell Valve system within the 35-inch wheel model and a couple of 1/2 instances the vary within the new 37-inchwheel model. 

The bigger 3.1-inch diameter anodized aluminum shock our bodies are “specifically designed to face up to the upper inside pressures created by the brand new digital valve’s wider dynamic vary.”

Shocks are specifically tuned for the 35- or 37-inch tire and provide a half inch of additional carry for the bigger tire.

Fox stated it additionally retuned and up to date the mechanical damping of entrance shocks to take care of the few forces generated by way of a extra aggressive tire with elevated wheel journey and up to date suspension.

For extra info, go to the Fox web site.


Larry Edsall

A former every day newspaper sports activities editor, Larry Edsall spent a dozen years as an editor at AutoWeek journal earlier than making the transition to writing for the online and turning into the creator of greater than 15 automotive books. Along with being founding editor at ClassicCars.com, Larry has written for The New York Occasions and The Detroit Information and was an adjunct honors professor on the Walter Cronkite Faculty of Journalism and Mass Communication at Arizona State College.