Bos Deville FCV fork review

Incredible grip and support if you’re patient with tuning

Our rating 
4.0 out of 5 star rating 4.0
GBP £1,000.00 RRP

Our review

Limited, flexy chassis options but offers incredible grip and support if you’re patient with tuning
Buy if, You’re an expert fork tuner and subtle trail ninja who likes to live life through the front wheel
Pros: Stellar tyre flattering traction and sensitivity anywhere in the stroke, beautiful build quality
Cons: Flexy, noisy, narrow damper bandwidth and coarse adjustment needs very careful tuning
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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. But jf there’s a model to fit your bike 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.

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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 lead to 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.

It’s enough to make even an average tyre feel amazing

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 firm’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. 

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. 

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

Product Specifications


Name Name, 0, 10, Name, Deville FCV fork
Brand Brand, 0, 20, Brand, BOS

Weight (kg) Weight (kg), 2, 0, Weight (kg), 2.01
Fork Offset Fork Offset, 2, 0, Fork Offset, 4.3
Travel Travel, 2, 0, Travel, 160
Leg Diameter Leg Diameter, 2, 0, Leg Diameter, 34