FSA's New High-End Crankset Skips the Carbon - Taipei Cycle Show 2019
FSA's aluminum KFX crank arms are machined in two separate pieces before being glued together.
If you want lightweight and high-end components, and especially cranks, the usual answer is carbon fiber. But FSA, who have plenty of fancy carbon things in their catalog, is going a different route with their upcoming aluminum KFX arms.
There are countless alloy cranks out there, though, so what's so interesting about these? Instead of machining them from a single piece of aluminum as per usual, they're made in two halves before being glued together. Yes, they're glued.
See those ridges and channels? They slot together very precisely to create a single unit.
Now, if know Cannondale well, that process might sound a bit familiar; they do a similar thing to make their impressive Hollowgram Si arms. The idea is that by machining them in two halves, FSA can remove as much material from the inner face of each arm as possible, making for a hollowed-out structure that's said be relatively lightweight yet strong enough for downhill and enduro use.
One arm is left with very precise channels cut into the mating face, while the opposite arm gets thin ridges that slot into said channels and, with the help of some powerful glue, make for a single crank arm.
Machining the arms in two pieces lets FSA remove material from inside that they otherwise wouldn't be able to reach.
I was told that they'll weigh in at around 520-grams (arms and spindle) so while they're certainly in the svelte category, they aren't the lightest around, either. FSA doesn't have any plans to move away from carbon fiber, they told me, only that they wanted a solution that's relatively lightweight but without the sometimes fragile nature of carbon. There's no word on an MSRP yet, but you should see them on shelves by late-summer.
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Apparently it's a pain in the ass to glue aluminium because of the thin layer of oxide layer that severely weakens the bond.
In the bicycle industry, a good example of course is the glued connection between the CFRP tubes and the titanium lugs of the Atherton/Robotbike frames. It doesn't go anywhere. That said, I think the Robotbike process is better thought out. They have a hole in the lug for air to escape so that the glue covers the entire surface it needs to cover. From what I see here, chances are pockets of air can't escape pushing back the glue from where it needs to go. But that's just armchain engineering of my part of course. It may just work out fine
The sleds are just over 400 lbs now with 150ish HP.
(just make the hole bigger so we can store a cliffbar in cranks)
Seriously, microwaved marshmallows is a powerful glue, we stuck a potato to a plate! (They also expand like crazy in the microwave)
The question is when does the patent run out, I seem to remember it doesn’t cover Europe so fair game....
That gets me thinking!
Most patents are actually there for tax reduction reasons rather than new inventions @justanotherusername:
Maybe better not to say that out loud, people will think you are crazy. (you’re right though...)
Trolls, ya’ll too funny!!!
Sounds like you better start walking.