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Is FSA About to Launch a 13-Speed Wireless KFX Drivetrain for Gravel or MTB?

fsa we 13 speed cassette derailleur drivetrain gravel mtb wireless electronic
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Two recently published patents from Tien Hsin Industries, the parent company of FSA, suggest that a 13-speed Wireless Electronic Groupset could be on the way soon. Will it mean the first FSA KFX mountain bike groupset?

The first patent – US11529827 – depicts and describes a 13 Speed Cassette with a fairly wide 10-48T sprocket arrangement, while the second – US11560200 – describes a wireless electronic rear derailleur with a clutch mechanism and the ability for non-contact charging…

Is an FSA 13-Speed Electronic Drivetrain on the Horizon?

The 10-48T cassette shown in US11529827 would give this hypothetical FSA 13 Speed drivetrain a 480% gear range, wider than Campagnolo’s Ekar 13-speed 9-42T cassette that delivers a 467% range, and wider than the more niche Rotor 1×13 gravel 10-46T, but less than their 10-52T MTB variant.

fsa 13 speed cassette patent sprocket arrangement 10-48t

The FSA 13-speed sprocket breakdown is as follows: 10-12-14-16-18-20-22-25-28-32-37-42-48.

My eyes hurt. That translates to steps of 2-2-2-2-2-2-3-3-4-5-5-6… tighter spacing than you get on most modern wide-range cassettes thanks to that extra cog, much like Campy explained with Ekar.

FSA KFX wireless electronic drivetrain, 13-speed gear ratio step comparison

Not only is its range wider than any of Campagnolo’s 13 Speed Cassettes, it also offers a different perspective on gear spacing (Ekar in gray, above). Presumably, with more off-road focus, it gets bigger steps percentage-wise between the two smallest (fastest) cogs, then a more consistent 10-15% gradient throughout the rest of the cassette (see that orange line above).

The spread is more comparable to that seen on wide-range cassettes for MTB such as the 12s 10-52T Eagle from SRAM (in blue, above). But the FSA 13-speed solution delivers more consistent steps at slower speeds (big cogs) compared to SRAM’s ramp-up to bail-out gears approach.

fsa we 13 speed cassette patent image exploded diagram adapters

An exploded diagram shows that the sprockets of the cassette are manufactured in three separate blocks. These are fixed to one another via a multi-faceted multi-stepped carrier, or sprocket base (orange), and a second adapter (purple) that itself threads onto a central region of the largest block (green). While that largest block is sleeved onto the freehub (looks to be XD/XDR), the central sprockets and outboard sprockets are coupled to it via the sprocket base and this second adapter that makes use of a pressing portion (320) and a friction member (red) in a sort of press-fit arrangement.

A wireless FSA KFX 13 mountain bike derailleur?

FSA KFX WE 13-speed cassette derailleur drivetrain gravel mtb wireless electronic

As for the Wireless Electronic Derailleur itself shown in US11560200, the exact number of gears it can shift through is not specified. The presence of a clutch mechanism (see below) does indicate its intention to venture off-road onto unpredictable terrain where there is greater scope for bumps, holes, and larger features to give that lower chainline a good shaking. Paired with the abovementioned cassette which bottoms out at 48T, it seems it would be most likely to find its home on some kind of racing-focused mountain bike or maybe a super adventurous drop-bar offering.

fsa mtb derailleur wiress electronic damping cage movement clutch one way bearing assembly

In terms of bicycle derailleurs, what you and I would normally think of as the clutch is actually referred to as the “damping member” in the patent from Tien Hsin Industries – parent of FSA. The damping member is a one-way bearing (red, above) positioned about the rotation axis between the derailleur’s main body and the cage assembly; i.e. at the P-Knuckle.

FSA KFX WE 13 wireless electronic mountain bike derailleur mtb gravel motor layout

That’s important because the patent describes a second clutch mechanism integrated within the shifting portion of the derailleur, the purpose of which seems to be to add lateral stability to the shifting mechanism. It can automatically and electronically disengage and engage as necessary, protecting itself in the event of lateral impacts. The shift motor itself is located on the outboard linkage of the derailleur’s parallelogram (52 in cyan, above) with force driven through the meshed gears (orange) about the red-colored pivot in Fig. 2.

A second point of interest on this potential new derailleur from FSA is its non-contact charging capacity. In some embodiments, the derailleur features removable rechargeable batteries (underneath P-knuckle, in Fig. 2), but in others the batteries are much smaller and can be charged through inductive charging.

fsa mtb gravel drivetrain 13 speed wireless electronic derailleur inductive charging circuit non-contact

Indeed, the patent document describes a wireless charging function housed within an extra unit labelled as 12a in Fig. 28 (light blue). The nature of the actual wireless charging device isn’t described; it mentions only the portion of the derailleur designed to carry out the inductive charging of its batteries. Inside the wireless charging unit (shown in Fig. 25) is a wireless charging circuit (dark blue), a coil (yellow), and the rechargeable batteries (pink). An alternate configuration, and alternate positioning, is also shown in Fig. 28.

The document reads, “By utilizing inductive charging technology and by disposing the coil for inductive charging on the components of the rear derailleur, the rechargeable batteries of the rear derailleur could be charged more conveniently, without the need to set a charging interface on the battery module, preventing the batteries from damaging due to the worn charging interface”.

shimano non-contact charging system ebike wireless charging electronic suspension components dropper post lights
Shimano filed a patent centered around non-contact charging of eBike components during riding

It’s not the first time we’ve seen a patent describing use of inductive charging for bicycle components. We recently discussed a patent from Shimano that proposed use of the technology to charge multiple electronically-actuated bicycle components. Shimano is even considering the use of magnetic resonance to charge eBike components.

About time?

Ever since we set eyes on Kevin Miquel’s FSA-sponsored Sunn Kern at EWS Zermatt in 2020, we have wondered when FSA would finally take the plunge with a dedicated off-road drivetrain the team had been teasing. The FSA-sponsored rider was then running their Afterburner wheelset with the SL-K crankset with a 36T chainring, but they were paired with a SRAM cassette and SRAM derailleur. We were told at the time that a 12-Speed Electronic Group from FSA was on its way. But. while we’ve since seen the K-Force 12 Speed WE for road enter the market, there is still no dedicated off-road group from the Taiwanese manufacturer.

That seems likely to change in the not-too-distant future. FSA KFX WE 13 could be just around the corner…

There is no comment from FSA at this time.

FullSpeedAhead.com

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21 Comments
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Andrew
Andrew
1 year ago

It amazes me that FSA continues to develop drivetrains despite the challenges they’ve faced at breaking into the mainstream. Clearly they have deep enough pockets that they can afford to do this development and hope that they’ll eventually succeed at making it commercially viable.

myke
myke
1 year ago
Reply to  Andrew

Ya, well that goes for anything FSA. The company really burned a lot of people’s trust. Their groupsets have always been fringe with little acceptance. I am with you but, as an OEM I would assume they like to stretch their abilities.

Jamie
1 year ago

FSA had a giant flop with one groupset and they decide to dump money into R&D for something that is going to be their own stand-alone group compatible with nothing else on the market. The mind boggles.

Andrew
Andrew
1 year ago
Reply to  Jamie

My thoughts exactly – Deep pockets I guess….and hopes that eventually they’ll break through?

Fake Namerton
Fake Namerton
11 months ago
Reply to  Andrew

Either that or we’ve been mislead about how expensive it is to actually develop groupsets as a means to get us to pay ever increasing prices for said products.

Sevo
Sevo
1 year ago

You have misread the value of the Ekar cassette range and thats the multiple one tooth only in the small cogs and that’s a big part of its appeal. Extra overall range is not all That important except for loaded riding. Keeping your cadence constant as you shift is more important than range.

Grillis
Grillis
1 year ago
Reply to  Sevo

For gravel, perhaps. Less so for mtb.

satanas
satanas
1 year ago
Reply to  Sevo

Ekar is only useful if you’re racing and/or a big gear pusher – the gaps in the midrange are horrendous. IMO this FSA cassette is much more reasonable, as is the GRX 11-34.

FrenchPress
FrenchPress
1 year ago

Usually I’m all for “at least they are giving it a go” – but come on. FSA has been working on road group for almost a decade that no one has seen TBH. This is nothing but more vaporware from them.

mike
mike
1 year ago

Who cares, nobody is going to buy it.

eddiepliers
1 year ago
Reply to  mike

To be honest, if anything I get comes with FSA, I change it out immediately

Fake Namerton
Fake Namerton
1 year ago
Reply to  mike

You’re right but these dweebs will downvote you because they’re idiots.

Michael
Michael
11 months ago
Reply to  Fake Namerton

who hurt you?

Mike
Mike
1 year ago

FSA nailed the gear ratios – I always hated the 18t to 21t jump in every 12 speed cassette. 10-48t range is also perfect for me for XC racing.

One problem… another f*ckin’ freehub standard!!!

Colin
Colin
1 year ago
Reply to  Mike

Probably not another freehub standard. It appears that they uses the SRAM XD/XDR (probably XDR as it is long and will accommodate the additional gear easier) interface.

blablabla
blablabla
1 year ago
Reply to  Colin

If it’s XD, then it’s fine. I doubt they’d use XDR, since it would also require a rear road hub, which almost nobody has in MTB bikes.

Stefan
Stefan
1 year ago

Based on some of the comments, maybe fsa’s goal is to be a patten machine VS a delivery business

Exodux
1 year ago

While I’ve never seen a FSA drivetrain on the road, trail or even at a retail location, I welcome this attempt and hopefully someday in will be a viable alternative to Shimano, Sram and Campy. I believe in having more choices is a good thing.

Roger Pedacter
Roger Pedacter
1 year ago
Reply to  Exodux

My girlfriend in Canada says all her friends ride FSA exclusively

Fake Namerton
Fake Namerton
1 year ago

Who in the world is riding FSA groupsets?? Sounds like the type of jabroni’s who say they prefer RC cola over actual drinkable soda.

Fitness
Fitness
11 months ago

7 people out there who will actually buy this must be very excited

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