FSA reveal K-Force Light Compact BB386EVO chainset

Stiffer and lighter chainset has been two years in development + video

by David Arthur   June 25, 2013  

FSA have unveiled their latest flagship chainset, the K-Force Light Compact BB386Evo, which is stiffer, lighter and offers more precise shifting than any of their previous offerings.

They've been two years in development and they have a new four-arm five-bolt spider, with one bolt concealed behind the crank arm. The power you apply to the cranks isn’t equal through the pedalling stroke, the load peaks when the leading crank arm is roughly level, says FSA. So by rotating the spider and placing the fifth bolt behind the crank arm, the design puts extra strength where it's needed most in the pedal stroke.

They call this Asymmetric Bolt Spacing (ABS), and it’s similar in essence to the idea behind Shimano’s 9000-series chainset. Those have a four-bolt spider and they've placed the four arms where they feel the areas of highest stress are in the pedalling stroke. Both have in common hidden bolts for very clean aesthetics.

FSA have also developed new ABS chainrings, which are 3D forged and CNC machined 7075 aluminum, with teeth profiles and shift ramps that they claim delivers crisp and precise shifting. The crank arms are made from hollow carbon with a unidirectional finish, and they weigh a claimed 584g. 

It’s available in a Shimano 11-speed version and there’s three crank arm lengths (170, 172.5 and 175mm) and the four-arm BCD accepts both compact and standard chainrings. They will offer the choice of 46/36T, 50/34T, 52/36T and 53/39T.  At the same time as making all those changes, FSA have given the cranks a fresh new look that is a bit of a departure from their previous models, a bit sleeker and more subtle we reckon. There’s also a plain black version.

There’s no word on availability or pricing yet, but they’ve launched them just before the Tour de France so expect to see a few riders pushing these cranks in the Grand Tour. We wouldn’t imagine they’ll be available until after the Eurobike show in September. As for pricing, there’s no word on that yet, but with the previous version of these cranks costing £599.99, we expect them to be in the same ballpark. More at www.fullspeedahead.com

6 user comments

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I reckon the Swedish tyre-slashing man would need a heavy-duty wrist splint after coming across this little beauty Nerd

neilwheel's picture

posted by neilwheel [130 posts]
25th June 2013 - 18:38

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So plenty of heavily discounted old style k force light chain sets to be had then - good enough for 99% of riders - you chose Devil

Pastaman

posted by pastaman [210 posts]
25th June 2013 - 22:37

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The paint job on the crank arm looks dodgy, you'd think they would have cleaned that up for the
promo photographs Thinking

Yes the Swedish bike sex man is gonig to faint when he cops an eye full of these Smile

Endorphines going up and adrenaline going down, who needs drugs?

posted by banzicyclist2 [186 posts]
26th June 2013 - 7:44

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I think its the 'grain' of the carbon fibre. The actual paint finish on the centre of the crankset won't last five minutes though - especially wearing overshoes like your man in the video. Having said that I'm always suspicious of some whose bike doesn't have that tell-tale rubbed smooth crank.

arrieredupeleton

posted by arrieredupeleton [536 posts]
26th June 2013 - 9:25

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banzicyclist2 wrote:
The paint job on the crank arm looks dodgy, you'd think they would have cleaned that up for the
promo photographs Thinking

How do you mean dodgy?

David Arthur's picture

posted by David Arthur [1414 posts]
26th June 2013 - 9:25

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Agree - think the "dodgy" finish is almost certainly just the natural look of the carbon fibre. The FSA SL-K on my bike has a similar appearance.

I think this crankset looks great, but since I'm not ready to upgrade to 11 speed, it looks like I won't need to worry about the fact that I can't justify spending £600 on it!

Re: the paint rubbing off - I think that will depend on each individual's natural foot position. Some ride naturally more heel out, so would not be constantly rubbing the paint.

posted by Tjuice [105 posts]
26th June 2013 - 11:53

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