Sea Otter 2017: BOS Suspension – New Deville 35 Fork

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BOS Engineering today launched a brand new Deville fork and Olivier Bossard was on hand to explain all of the changes (and there are many) in person.


The new Deville fork has been redesigned from dropout to crown. The new fork is immediately softer and smoother looking, with shiny black 35mm stanchions and a much more organic look than the hard angled, gloss original fork. There’s more differences inside too.

Much smoother and lighter looking
All this tech won’t be cheap, with Euro/Dollar prices around $1600/€1600(!)

The fork itself is a hard hitting trail and enduro fork and (currently) will come in 27.5in with travel in the 150-170mm range. The new chassis has been updated with Boost 110mm spacing and a whole new bulged fork lower assembly. There’s a completely new air spring on one side and hydraulic cartridge on the other.

The new shape really is a lot more organic. The satin finish is lovely too.

The Deville’s crown is now a hollow unit to save weight (claimed weight for the fork is 1.9kg) and this has involved a redesign to make the crown deeper to keep the stiffness up.

Three adjustments on the right leg to control traction, stiffness and fork platform.
The arch is weight relieved to keep weight down
OK, that’s blue sky. We get it…
Screw-in thru-axle with a single bolt to secure it snugly

Part of the air spring redesign is the inclusion of spacers in the negative air chamber. The fork comes with three spacers (below) that let you fine tune the suppleness of the fork by reducing (or increasing) the volume of the negative air spring. This affects the fork’s performance on the early part of the stroke and determine how much help the fork gets to compress from the negative spring.

The three different negative air adjustments available.

The damping side of the fork has also had lots of changes. The sealed cartridge has a lot of adjustment – though BOS is keen to point out that it doesn’t have the common ‘High and Low speed compression’ adjustments, but rather a fork stiffness adjuster and a traction control. And that big red lever isn’t a lockout, though it does slow the fork down so that you can pedal, while still keeping suspension feel.

The FCV lives below that lower red bit and above the shim stack at the base.

The damping circuit also includes an FCV – or ‘Frequencies Control Valve’ where it’s said to be able to differentiate between movement from the rider and bumps from the trail. It’s one complex bit of engineering.

As well as this neat one-bolt system, the lowers have a new foam bottom out bumper.

The Deville is expected to start shipping some time in May, with a 29in (and/or 27.5in Plus) fork due at the end of the year.

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