Hiding on the back of that new Ridley Kanzo Fast aero gravel bike we spied yesterday is this curious internally geared Classified Hub, doubling up your gravel gearing. While gravel bikes are leading the drop bar trend to ditch the front derailleur, this unique wireless shifting 2-speed internal gear Classified Power Shift Hub brings back 2x range and smooth gear steps – all while keeping all the functional improvements of modern 1x drivetrains. Here’s how it works (and it’s coming soon)…

Classified Hub, wireless 2x internal hub gear, plus a 11sp cassette

Classified Hub, Classified Power Shift Hub, wireless 2x internal hub gearing plus 11 speed cassette delivers wide range road gravel bike bikepacking drivetrain
images c. Classified, lead image c. Ridley

The secret is a special rear hub with a single step reduction set of planetary gears inside and a mostly conventional 11-speed cassette on the outside. A wireless shifting setup controls the internal 2-speed planetary gear shifts, while you use any standard 11-speed clutched rear derailleur  to move through shifts up and down the cassette. You get 2x gearing with 1x chain retention, boosted tire clearance & external simplicity, even on bikes that are 1x-only!

How does it work? It’s Classified!

Classified Hub, Classified Power Shift Hub, wireless 2x internal hub gearing plus 11 speed cassette delivers wide range road gravel bike bikepacking drivetrain

At your handle bar, use a standard electronic shifter or satellite buttons (it appears to work with current Di2 buttons) to send the shift signal via a control module mounted in your left bar end (the right one has your Di2 control module, these days) wirelessly back to the Smart Thru Axle.

Classified Hub, Classified Power Shift Hub, wireless 2x internal hub gearing plus 11 speed cassette delivers wide range road gravel bike bikepacking drivetrain
Classified Smart Thru Axle

Yes, it requires a smart thru-axle (that’s what we spotted in that teaser Kanzo Fast image above from Ridley). The 12x142mm axle is micro-USB rechargeable for three months of riding and transfers the wireless shift signal through a contact-less interface to the shift mechanism inside the closed Power Shift Hub unit.

Classified Hub, Classified Power Shift Hub, wireless 2x internal hub gearing plus 11 speed cassette delivers wide range road gravel bike bikepacking drivetrain

The sealed Power Shift Hub assembly is where the magic happens. This is where the two-speed planetary gears live, protected from the elements. Shifts are electronically actuated, but the Power Shift Hub system requires no external power, instead taking actuation energy wirelessly via induction from the Smart Thru Axle for 10,000 shifts on a single charge.

Classified says it takes just 150 milliseconds to shift, even under full load.

Classified Hub, Classified Power Shift Hub, wireless 2x internal hub gearing plus 11 speed cassette delivers wide range road gravel bike bikepacking drivetrain
Classified hubshell (left), Power Shift Hub unit (right)

But wait there’s more. The Power Shift Hub assembly can quickly slide in & out of the alloy hubshell, allowing you to have one Power Shift Hub setup that can swap back and forth from several condition-specific wheelsets (much like the recent Kindernay hub system).

On the outside of all that, Classified’s proprietary interface 11sp cassettes let you pick the gearing you need, and interface with your conventional 1×11 drivetrain. The result: 1 chainring, an 11-speed cassette, and wide 22-speed double drivetrain.

What does Classified Hub do to Gear Ratios?

Classified Hub, Classified Power Shift Hub, wireless 2x internal hub gearing plus 11 speed cassette delivers wide range road gravel bike bikepacking drivetrain
Classified cassette

To make the entire system work you need to use one of Classified’s proprietary cassettes, which now limit you to 11-speed drivetrains (sorry no SRAM AXS fully-wireless setups, just yet). That probably shouldn’t be too big of a problem, Classified machines their 4 cassette options from mono-block, tool hardened steel so they should be both light & durable. Available 11sp cassettes include 11-27, 11-30, 11-32 & 11-34 gear ratios. Those seem slightly big for gravel, but the 2sp planetary gears should take care of that.

The Power Shift Hub runs in two ratios – straight 1:1 where you get the gearing you see from the outside, and a UnderDrive ratio of 1:0.686 to expand the low range wider than the cassette would suggest, just like dropping to a little chainring up front in days of yore.

Classified Hub, Classified Power Shift Hub, wireless 2x internal hub gearing plus 11 speed cassette delivers wide range road gravel bike bikepacking drivetrain

So let’s talk possible gear ratios… Classified says you need to run a minimum 40T up front, which with the widest 11-34 cassette would give you a lowest possible gear & widest spread equivalent to a 11-49.6 cassette – or 450%. Not quite SRAM Eagle 500%, but bigger & lower than the 381% you can get from 1x GRX (whose easiest compatible gearing is 40T x 11-42.)

Classified calls it comparable to a regular 2x setup, where a road compact 50/34 has 1:0.68 reduction and new SRAM 43/30 1:0.70 reduction. So you can opt for a 50T ring to get the same road-ready gearing or go down as far as 40T for a more gravel friendly-setup.

But why?

Classified Hub, Classified Power Shift Hub, wireless 2x internal hub gearing plus 11 speed cassette delivers wide range road gravel bike bikepacking drivetrain

You (and I) might ask, why all the hassle when perfectly functional, cheap front derailleurs still exist? One simple reason is that a lot of new bikes have lost any option for a front derailleur (you/we can certainly argue the rationale for that) whether for improved tire clearance, improved aerodynamics, better 1x chain retention, or maybe even simplicity. Classified is simply clawing back 2x range in a system that shifts better under load (or even while freewheeling) while giving you all the benefits that 1x sold you on.

Classified Hub, Classified Power Shift Hub, wireless 2x internal hub gearing plus 11 speed cassette delivers wide range road gravel bike bikepacking drivetrain
c. Classified

Weight impact is an obvious concern, but they claim says that “a bike equipped with Classified and 1x GRX Di2 setup weighs about the same as a bike with a traditional 2×11 GRX Di2 groupset and a DT Swiss 350 hub”. There are obviously ways to build a lighter setup, but any total system weight penalty appears to be minimal.

Classified Hub, Classified Power Shift Hub, wireless 2x internal hub gearing plus 11 speed cassette delivers wide range road gravel bike bikepacking drivetrain
c. Classified

And while the Power Shift Hub is more mechanically complex than a standard cassette hub, Classified says it requires no additional maintenance and “has an operational lifespan exceeding the lifespan of a bicycle’s internal systems”. Bearings are subject to normal wear, and Classified says they offer service parts to get you back rolling quickly if there is ever any issue.

So…

How do you get one & How much does it cost?

Classified Hub, Classified Power Shift Hub, wireless 2x internal hub gearing plus 11 speed cassette delivers wide range road gravel bike bikepacking drivetrain
c. Classified

For now the Belgian developed & produced Classified hub is only being offered as original equipment on complete bikes. The Classified Power Shift Hub system is manufactured in Turnhout, Belgium. No official statement has been issued of which bikes will be included, when it will be available, or how much it will cost.

Classified Hub, Classified Power Shift Hub, wireless 2x internal hub gearing plus 11 speed cassette delivers wide range road gravel bike bikepacking drivetrain
c. Classified

But… that lead image that came from Ridley would be a good hint. And how about all of these other smaller images that comes from Classified’s own website, clearly showing the most complete views we’ve seen of that new Ridley Kanzo Fast aero gravel bike. And having been ridden from snow to sunny cobbles, it seems like they’ve been ready for a while…

Classified Hub, Classified Power Shift Hub, wireless 2x internal hub gearing plus 11 speed cassette delivers wide range road gravel bike bikepacking drivetrain
c. Classified

That bike is clearly equipped with Shimano GRX Di2 1x, a one-piece carbon cockpit, carbon wheels & the new aero carbon gravel frameset. Based on Noah Fast pricing, you’re probably looking a complete bike around 7500-8000€. No we wait and see when the Kanzo Fast gets its official debut…

Classified-cycling.cc

18 COMMENTS

  1. Cool. This solves a lot of problems for some cyclists. But, why yet another hub-cassette interface standard? Is it because they needed more space for the internal gears? Also, I’d love to see 1 cassette with a 16 tooth.

  2. Interesting idea. Current bike drive-trains (chain and gears) are very efficient. I wonder how many watts this hub will eat up in losses with the planetary gear set? And will you only see these losses in one of the two modes?

    • Really cool design. I’d also be curious about the friction created by those gears. With a 1x setup you’re already accepting a loss of watts to chain deflection in the high/low gears.

  3. I’m here for it. Soon we’ll welcome back front derailleurs on gravel and mountain bikes…

    I also am interested on if this could be run with a front derailleur. Lots of recumbent trike people run 3×9 derailleur systems with dual drives..which I guess is a 3x9x3 system?

    • So long as the derailleur can handle the total capacity, you can rig it up, but i wonder if the torque will be too much. SRAM’s DualDrive was similar in concept, and also had a similar low chainring caution. I ignored it for an 80 year old who just needed to keep pedaling, and he has ten years on the system now.

      • How often is your 80 year old standing on the pedals in the smallest gear? I borrowed my wife’s real wheel once (back in the days of all mountain bikes being 3 x 9 on 26″ wheels and tubes) when I found my tire was flat and I was already late to meet my friends. It was horrendous, the freehub kept skipping under load. I put it back on her bike after my ride and she rode it like that for a couple of months without a problem. Eventually I pulled it a part and found one of the pawl springs was broken and the grease in it was sticky.

  4. Big complication, heavy and (probably) very expensive for just a 450% range. There are lots of simple and cheap options to achieve better range (even more than 500%) on 1x drivetrain and road shifters, like jtek or tanpan, garbaruk cassettes and derailleur cages, gevenhalle shifters…

    • I think that they made the right decision to use it for the underdrive. Hammerschmidt’s was the opposite, and the added drag, combined with the added drag of going faster made it kinda demoralizing. I imagine that, used as a bailout, with the added mechanical advantage, and at lower speed, the extra drag will be more acceptable.

  5. I want to be able to switch between 1:1 and 1:0.33 so that with and 11-28t cassette you’d have the full 11-28 range than be able to drop down to the 0.33 ratio and the 11t at the same and have the equivalent of 33-84t for the easy gears. The trick would be getting Di2 and the hub shift to synchronize so make moving the chain from one end of the cassette to the other as quick as possible.

  6. Or we could demand bikes with proper gear ratios. The whole 1x was such folly tht many bought into and now we are faced with these overpriced overly complex band aids. Two thmbs? two derailleurs and done.

  7. Yeah, I’ll third that question about friction. I could imagine that with only one shift to make, as opposed to something like a Rohloff with 14 gears, they could perhaps optimize some aspects to further reduce friction. As far as Chris’ point about if you only experience the losses in one of the 2 gears, it sounds like you would, as the larger gear is a 1:1 and the second gear is an underdrive, that reduces the size. I find this interesting as this system is perhaps most akin, conceptually, to the Truvative Hussefelt (which was a 2x internal gear crank for those unfamiliar with it), that was also intended to compensate for the loss of range when MTBs started to go the 1x route many years ago. The thing that is interesting is that the Hussefelt had a 1:1 with an OVERdrive, with the idea being that friction is least welcome when you are climbing, whereas when you are carving up a descent on a trail, power loss is not your limiting factor. This design takes the opposite approach, but if they haven’t managed to minimize the friction to previously unseen levels I could imagine it feeling like a real drag (no pun intended) when you go to hit that lower range on a climb.

  8. You forgot to mention that those 1x options have larger gaps between ratios, which on road and faster gravel, are pretty annoying.

  9. Makes no sense, planetary gear will eat about 4% if it has good quality parts. An eagle cassette will have more range, will be more intuitive to shift, better efficiency simpliicity and lightness. This gap obsession comes from rider that learned to ride with a road bike, on a 12sp eagle cassette gaps are really fine, just HTFU.
    Many lab studies were done and showed no measurable loss in efficiency with 20% variation of cadence around prefered cadence. So you’ll lose much more efficiency in the gear than any imagined gaiun with the gap. Long live 1X and its simplicity.

    • If there is no measurable loss in efficiency with 20% variation of cadence wouldn’t that apply to road bikes as well? If so, why don’t roadies ditch their front derailleurs for many of the same reasons?

      • Because traditions. Important to note the alpha blue dumb bikes add dumb 10 tooth sprocket (for road racing) and not enough range.

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