BOS Deville FCV review£1,000.00

Fantastic grip and support if you take the time to tune it properly

BikeRadar score4/5

The Deville fork from legendary French damper specialists Bos is now showing its age with very limited chassis options and it’s not as stiff as chunkier forks from competitors. If there’s a model to fit your bike, thouhg, the latest FCV damper offers those patient enough to tune it right incredible grip and support that still makes it a blisteringly quick aggro fork.

With no 29er or Boost options and an irritatingly small 160mm brake mount as standard the Deville chassis is looking dated this season. 

Despite 34mm stanchions, cut outs in the skinny brace and obvious twist and tuck if you’re using a big rotor and bars to maximise leverage it’s still over 2kg too, which puts it into the same ballpark as much stiffer forks like the Rock Shox Lyrik and Fox 36. Tyre/fender space is also limited if you’re thinking of going 2.4in or bigger on rubber. 

The stepped 15mm axle system with its flick open winding handle and locking cam are beautifully machined to underline the premium quality and cost although you need to keep it clean particularly in the cold. 

The cam closed dropout eliminates side loading of the lower legs and hub so there’s no interference with stroke smoothness or hub bearing spin. There’s a 20mm axle kit, too, if you’re still keeping it old school.

There’s absolutely no forgiveness in what will happen halfway down the hill if you get it wrong

There’s more acutely precise sophistication hidden inside the Deville, too, and while the chassis is essentially unchanged for this year the new FCV damper has come from the brand's top level rally experience via the Idylle DH fork. 

This Frequency Control Valve is designed to increase initial sensitivity and counter Bos’s previous reputation for stubborn starts and it goes a long way to making it as smooth off the top as the best modern forks. 

The narrow damper bandwidth and coarse adjustment means the Deville FCV fork requires very careful tuning
The narrow damper bandwidth and coarse adjustment means the Deville FCV fork requires very careful tuning

Get the balance of low and high speed compression right and you’ll access a fantastic balance of support for pushing crazy hard through corners but ultra sensitive traction at any point in the stroke to keep you railing however random it gets. 

It’s enough to make even an average tyre feel amazing and lets you stay head up, heels down and bars slammed even when you can feel the fork writhing all over the place. 

Finding this sweet spot isn’t easy, though. Coarse adjustment means just a single click of either low or high speed compression can make a big difference and a narrow bandwidth of what works and what doesn’t means there’s absolutely no forgiveness in what will happen halfway down the hill if you get it wrong. 

The damping oil flow is also noticeably vocal when working hard which is either encouraging/endearing or offputting depending on your view.

This article was originally published in Mountain Biking UK magazine, available on Apple Newsstand and Zinio.

Guy Kesteven

Freelance Writer, UK
Guy started filling his brain with cycle stats and steaming up bike shop windows back in 1980. He worked the other side of those windows from '89 while getting a degree in “describing broken things covered in mud" (archaeology). Dug historical holes in the ground through the early '90s, then became a pro bike tester in '97. Guy has ridden thousands of bikes and even more components the world over since then and can remember them all in vivid, haunting detail. Can't remember where the car keys are, though.
  • Age: 45
  • Height: 180cm / 5' 11"
  • Weight: 68kg / 150lb
  • Waist: 76cm / 30in
  • Chest: 91cm / 36in
  • Discipline: Strict sadomasochist
  • Preferred Terrain: Technical off-piste singletrack and twisted back roads. Up, down, along — so long as it's faster than the last time he did it he's happy.
  • Current Bikes: An ever changing herd of test machines from Tri bikes to fat bikes and everything in between.
  • Dream Bike: His Nicolai Helius AM custom tandem
  • Beer of Choice: Theakston's Old Peculier (not Peculiar)
  • Location: Yorkshire, UK

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