Since filming this video, a few people have been in touch and said that I was quite charitable with the power loss on the classified hub. The general consensus was based on the likely geometry, 90-92% would be more appropriate. A couple of papers for you to read Someone with their right hand as their best friend: www.researchgate.net/publication/226757576_Theoretical_and_Experimental_Efficiency_Analysis_of_Multi-Degrees-of-Freedom_Epicyclic_Gear_Trains Roymech for the practical calculation roymech.org/Useful_Tables/Drive/Gear_Efficiency.html It is worth noting that there are no hard figures on Classified's website and their mitigation of the apparent loss is to take credit for the aerodynamic loss from the front mech.

I think people underestimate the amount of design, engineering, testing and innovation that Shimano has put into just chain and cassette technology, and making them work as good as they do.

I've been using the classified system for about 18mths. It's fully integrated with my left Di2 shifter and works really well. In terms of weight, I know they claim it is roughly the same as a 2x, but I think it's probably marginally heavier with the weight transferred to the back of the bike. Overall I'm a convert to the seamless nature of the shifting. Only lingering doubt is serviceability as I've had issues with play in the bearings. Classified ended up having to send me a replacement Powershift hub as the bearings can't be replaced on their own.

Bicycles are such efficient machines it is pretty hard to do something that doesn't make them worse.

I can't wait for the cycling press who have pushed 1x so hard to start espousing the benefits of the closer ratios and wider range this gives...

I have a bike with the Classified Powershift system from the bike manufacturer. It was the same cost as a SRAM AXS Force or Ultegra Di2. It's a better deal if you buy it as original equipment rather than converting a bike. My frame has no hanger for a front deraileur or chain guide. Mine is SRAM Force AXS rear and shifters and Red cranks and aero chainring with integrated powermeter. 1. There is essentially no weight penalty. The one piece cassette is 12 speed and weighs less than SRAM Red or Shimano Dura-Ace. I don't use a chain catcher (no way to mount one), and I have not dropped a chain since I got the bike 6 months ago. 2. For SRAM, the 12 speed cassettes start with an 11 tooth cog, not the 10 tooth, so less friction loss from small cog, and you can go bigger with 1x chainring. 3. The SRAM 1x Aero chainring has less deflection of chain line than a SRAM 2x system. I will have to measure, since I have bikes with both. SRAM AXS monitors how much time/miles you spend in the 12 rear rings, and spend most time in the middle 7, so chain line with 1x is really good. Even in 1 or 12 the difference is probably marginal between 1x and 2x at the inner and outer gears. 4. There are no pawls in the hub, so there is less friction when coasting whether in 1.0 or 0.697 internal gear. No significant sound from the wheel/hub when coasting. 5. Gerrard Vroomen has tested 1x vs 2x and has the data for the 1-2% aero gains. 6. Wheel switching is a piece of cake. The smart Thru axle only pairs with the bar end BT unit, not with the hub. You just unscrew the Thru axle without any tools, pop out the wheel, put in a new wheel with a Powershift hub, screw in the thru axle (without any tools) and away you go for the racers. 7. If you have a problem with the Powershift hub, call/email Classified and they will send you a new one while yours is being serviced. 8. The torque arm on the hub just swings around the axle and then touches the brake mount screw. When you tighten the thru axle, you have to move the torque arm to touch the brake screw. Easy. Mine was making some squeaky noise, and now Powershift has a plastic insert for the torque arm that touches the mount screw and eliminate the sound. They sent the plastic insert from Belgium in 3 days. All good. 9. I am not a pro racer, just an enthusiast. I cannot feel any loss of efficiency with the 0.697 internal gear vs my 2x Force bike. In fact, it's hard to tell the difference when riding in the virtual big vs small rings. Folks are complaining that with Garmin you have to choose a screen for either the rear gears or the front gears. You can't monitor both at the same time. 10. The thumb switch is very natural to use after a week of riding. Not a big deal. It just works perfectly. 11. Once you shift under power or going up a steep hill without dropping a chain (particularly in a paceline or local race) you will get the benefit of the system. I generate the same maximum watts when sprinting on the Powershift in the 11 tooth cog as I do sprinting with my 2x system in the big ring, both bikes with Quarq power meters. For early adopters there is a cost unless you get a special edition bike like I did. Once cost comes down and reliability is proven, more folks will choose this. I still love my mechanical 2x bikes, but this is better. Gerrard Vroomen told me that the initial Powershift 8 years ago was not good. Now, it is good. 12. Hambini may be right about efficiency, but I can't feel any power loss. As he said, needs more data.

I had a play around with one at my mate's shop and it was really good fun to play with, really easy to change gear under super heavy load (I was messing around on a 10% slop) BUT it is far too expensive!

That's a pretty good teardown based on the photos. About the only thing I'd doubt is bronze or brass gears, far more likely to be sintered steel, induction hardened. Same sort of thing as you find in impact drivers and demolition drills, and easily sturdy enough to take the loads involved. As far as efficiency goes, you're being pretty optimistic, I'd say. You could probably change the way it drives to put the lower efficiency at high speed with a bit of fiddling / more complexity, but I think your analysis of the setup is probably correct. You have a static axle as art of the initial design constraints, so why not use that to lock the sun gear, after all? It's not really unproven technology, though - epicyclic gears have been around forever, and, like you say, Sturmey Archer did it for years. and although they were limited to 3 gears, they were pretty much unbreakable. Fully enclosed gearbox drives do exist in the MTB world, that's probably where they make the most sense. Rode a friend's setup about 8 years ago, it was pretty damn good.

Put on a a customer's bike for last years master's world championship road race. Worked very well, friction isn't something I ever thought about. It did't seem bad at all. I'm a big skeptic when it comes to stuff like this by nature but I was pleasantly surprised.

So much negativity here; - fully integrated with di2 - cassettes are not even that expensive - wheel change is super easy. The unit in the HB is connected to the thru axle - not the hub - the use on gravel and/or MTB is great. - the large brands will go onboard but it takes a few years in OEM markets. - the shifting is better then any front mech can do, even Shimano - SRAM still isn’t capable of doing it. - the bearings inside the hub can be changed; albeit at Classified and they have a swap service for it.

If I could afford it, I'd try it on my gravel bike. This solves a lot of the trade-offs currently. Front derailleurs are problems when it comes to tire clearance, the more important mud clearance where the real gravel races are at (midwest USA), and dropper post control. The clay here is thick enough to actually drive your chain off the chain ring when it gets caked up. Roadies might not care, but roadies aren't actually important anyways.

I also sat on a bike equiped with a classified hub and it was an amazing try-out. Shifts were super snappy and quick and it felt a bit like a DSG gearbox compared to a manual gearbox. Really love the idea and the execution. Only the bluetooth dongle is a bit shait and it should talk to a di2 or axs lever. That would be the icing.

I'm waiting for the return of the triple chainset. might be wireless or electronic but the triple will be espoused as the best new thing EVER

As I have just bought a 1x set up I was semi tempted, even though the weight and cost were frightening. The watt loss was the final nail. Excellent review thanks so much saved me a fortune! Thanks :)

One thing you missed on the "pros" list is the ability to shift gears under full load and instantly. That being said I agree with your analysis on all fronts.

Looks like a well engineered and made component for the well heeled non racer

I'm really glad I found your channel. Keep up the great work, I love your content.

Another few factors with traditional derailleur drivetrains is the ability to use a variety of different sized cassettes, your local bike shop has cassettes in stock and in 5 years you're still going to be able to buy cassettes. I can also convert a wheel with a standard freehub body to different standards such as 10 to 11 or even 12. Will that be an option with the internal hub. I don't know about you but it seriously reminds me of the the sram 3×8 hubs from 25+ years ago with a few updates. It's worth noting that stopped hearing about the sram 3x semi IGH hubs because they simply weren't nearly as good in terms of weight, durability, efficiency, cost, user serviceability...

I would say that looks like an Edco/Recon manufactured cassette. The teeth shape and profile looks surprisingly similar to that of their Monoblock cassettes. Shifting on those is pretty sub par though compared to a Shimano 105 or Ultegra cassette. It's not desperately bad, but you can clearly feel a difference.

Awesome video - I learned something! I've been fantasizing about getting a road bike with a Rohloff or Kindernay gear hub to reduce my time spent on bike maintenance. Could you talk about these systems and if they make sense for a road bike in terms of efficiency and power losses or gains?

Hi and thanks for the video. I use the Classified system for more than 8'000km now. Many of your arguments are correct. In terms of efficiency I think your approach is too "academic" or numbers based. I never felt any difference between derailleur systems and this one. I also use power meters and the numbers from power consumption for comparable climbs give me same or even better climbing performance - to me the your argument "efficiency" is not confirmed - or not measurable. In fact the Classified system changes your driving habits - to the positive. On flatter sections during a climb, you just "slam" the front, instead of changing 2 or 3 gears in the rear. Don't care about chain line and having real 2 x 11 (22!) gears. Finally converted all my bikes to Classified and just love it. (By the way: chain life increased to 4'000km, instead of max. 2'500km)

I know for sure Light Bicycle can build a custom pair of wheels with the classified hub. With the hub itself (shell), costs are more or less the same of other hubs + you have to purchase the rest somewhere else. Was the first one asking them :D

I'm still interested in this technology for a gravel rig, which was it's original target anyway. 4% efficiency isn't at all an issue if you can run a really wide range of gears without massive jumps and a clutched rear mech.

Having a couple of Shimano.internal geared hubs, the drag is noticeable. Bought one for winter commuting. From a heated garage to work, didn't coast well. Was only 3 miles. Pushing it into the building, the pedals rotated with the hub. Maybe the Rolloff wouldn't be as bad, but even oil thickens in the cold.

Classified stated that the "Direct Drive" is 1:1, so this is a really attractive option for people like myself who are already running 1x. This system would simply add a low end "bailout" for the occasional hill. I wouldn't care about the reduced efficiency in the "Under Drive" condition, it would just be nice to get up the climbs in a bit higher cadence.

Where did you get 96% from? In their review GCN quoted ~99% for the 0.7 ratio.

I agree with most the things. But I will say when the Rolhoff hub came out like 2 decades ago I thought it would never make it. Heavier, expensive, gear range was not as wide as a 3x9 at the time, AND to need a special frame made with the specific drop out to accommodate it. But fast forward…it’s a durable beast chosen by many hardcore tourist/commuters. I still have the old Schwinn two speed kick back! I wonder how efficient that is:) great video as always Hambini.

Will this be compatible with an absolute black hollow cage rear derailleur thingy?

Actually this is an old idea. I used to have a Schlumpf MountainDrive in my daily driver a couple of years ago. Compared to grinding in a much higher gear the efficiency hit was about 5-7%. That's not nothing, but getting a bike with lots of (travel)cargo up a hill, it was well worth it. The reduction was 2.5x, so I could ride a 52 chainring and reduce it to a 21. This meant comfortably spinning 300W at 85 rpm up any hill. For my occasional climbing, it was more than perfect.

I have a Classified hub and it’s very nicely integrated with my Di2. Classified did the integration for me. Separately- Hambini, I’m a fan of yours, but I think I’m this instance you should do more due diligence before slamming a product. How about actually buying a hub and testing it / tear down??

The planetary gearbox inside the classified hub reminds me very much onto the Schlumpf speed drive.

TraceVelo made a video about the chain shifting problem, he forgot to put a spacer behind the cassette. After this fix it worked ok. I ordered some bearing from you, excellent service

Thanks Hambini for a professional speculative "review" of this product. I see in a comment earlier there is a player of the hub system and it is well received...

I got to try the classified hub a couple days ago, they had it intigrated into the front Shimano Di2 shifter, pretty neat. Overall it was nice, but I was not blown away. I am curious if this product is gonna get pupulart or not, so far I have never seen or met anyone riding it or even talking about it.

some years ago I owned a bike with a Truvativ Hammerschmid Drivetrain - which was kind of similar, but the planetary drive was installed instead of the 2 front chainrings. The feeling of losing power was insane, so I knew from the beginning, that the Classified system won't work at all..... :)

As usual a well explained expose on what might, or probably might not, be the 'next big thing' in cycling. I'm with you Hambini - Don't think it will be adopted in large numbers UNLESS Shimano get behind it (which is doubtful).

Hambini tells it as it is... that's what's best about these videos...top man 👍

As you mentioned the Sturmey Archer three speed hub with cassette, how would this be an improvement over that much cheaper and simpler setup?

Awesome video! Certainly appreciate the valuable knowledge

My hunch is this system will not turn out to be successful but, like L shaped cranks or Biopace chainrings, but it's good to see people experimenting with this type of thing. Thanks for sharing.

It is a really interesting concept, do you think it would work better at the cranks instead of the hub ie Truvative Hammerschmidt cranksets from the 2000s? Mechanical planetary gear in the crankset to have a 2x set up with only one Chainring. It was relatively popular on Mountain Bikes around then. Sram probably has the patents on it locked down

Very good video and clear explanations ! I kind of feel that for years "gear box" system have been on the market. Al lot of good system able to replace the standard derailleur system (Pinion, Effigear even Shimano Nexus/Alfine ...) but all with the same issu of efficiency. I'm not sure they all use the same planetary system (?) but they all are less efficient than the derailleur as Classified .So maybe that could be an option for non-competitive cycling ? But then it's too expensive ...

Great presentation. I like the idea of a planetary gear that is not a Sturmey Archer, or the like, in the wheel hub with a derailleur. To make it worthwhile I think they need to make the rations such that this will substitute for the front derailleur entirely WITH a wider overall range then you would usually get. That would make it great for me, the commuter. However, the cost numbers I remember were higher or equal to the Rohloff. AND, the Rohloff is made to be used without any kind of derailleur at all. Much higher than a Shimano Nexus. I agree with your bottom line - too expensive for the casual rider, too complicated and risky for the racer. No customers will want it.

Thanks Hambini...very enlightening. Would love to see a video on Pinion gearbox effciency.

When you show efficiency for regular gears at 10:30, what is the difference between big ring/big cog vs small ring, small cog for the same ratio? Using big/big with equally bad chain line seems to feel a lot smoother to me.

There exists a sachs orbit hub like this haha. Quite old, but became a bit of a classic within its small fanbase i think

Sturmey did this style of hub, 3 speed epicyclic, triple sprocket, 3x3, 9 speed. I have one in my garage on a vintage tandem. It is interesting to see these reboots. .

I always look forward to a Hambini reaming.

Another con is the added cross chaining in the lowest gears, since you're always in the "big ring", They should make the front ring "axially floating"

Great video! Never liked internal gear hubs. Have a Brompton with Sturmey Archer hub and on the step up or down gears, it was harder to pedal. The frictional losses are real! Another problem with Classified hub is the battery. It's in the thru axle - propriety part, expensive to replace. I don't see a market for this product unfortunately.

Back in 1975 or 1875 or 1775 I was in high school and had my own bike shop. Sturmey Archer was everywhere, and I allowed (assigned) my brother to do all the internal gear hubs which was fine by both of us. The hub had a little plastic flip cap so an end user could squirt in some oil with a trigger driven hand held pump. Most people think that if a little oil is good then more is better, and others deicded to leave such things to "the pros" whom they never made it to see and they used leaded air (unleaded gasoline was a new thing) as a lubricant, so nothing could go wrong. Some were so maladjusted that the shift lever had ne effect. When gears are out of sight they are out of mind and we can guess how many people are either out of their mind or their mind is out of them. I think the sun and planet gear system is so old that it was developed by Copernicus (the dog in Back to the Future) because it takes a son of a female dog to build and sell such a thing. If they are well funded then maybe this is a front for something nefarious. Nice review, and I also believe the gear to be pinned.

Not one for the roadies but I’d be interested to see what you make of the schlumpf mountain drive. Similar concept but half the price and the planetary gears are in the bb shell instead of at the back. I worked on one recently and I was impressed (although I hated it at the time)

I have a classified hub and tested it on rollers. It's no more than 2-3% at 300w

Another solution to a non-problem. A 2 chainring system will typically provide a better chain line than single chainring. Front derailleur shifting on DI2 is lightning fast and auto trims. Maybe this makes some sense for an off-road system where mud can clog the front derailleur in extreme conditions?

Another typically fascinating review, even though I'll never be in the market for this anyway. cheers from cloudy Vienna, Scott

I own this system and installed it on my gravel bike with Shimano GRX 815. I have horrible shifting. I'm still trying to dial it in. I have a number of complaints about the system, but I have complaints about Shimano and SRAM's offerings as well. If I get it shifting smoothly, I'll enjoy having it.

"ring gear with planetary gears", "centrally pivoted sun gear" ... this was almost too much for my heart and soul. Totally fantastic; a video about cycling Utopia. But wait - you weren't FINALLY doing a video about the epitomy of transport endevour, the zenith of technological progress, the superlative achievement of human evolution, what we have been heading towards since we first decended from the trees?. Forget quantum physics, CERN or the James Webb Space Telescope: the Rohloff hub is humankinds greatest achievement . . Maybe next week

Finally a video that really explains how it works! Thank u!

Speaking of drivetrain efficiency, what happened to that Irish company that was claiming a new kind of chain that would boost DT efficiency to nearly 99%? They seem to have disappeared off the face of the earth, despite having notable backers and engineering via some fairly well respected engineering faculties at Irish & British universities. Edit: I see they're now targeting e-bikes / city bikes / cargo bikes / industrial applications, and selling track chainrings and sprockets as a set but without chains (useful :-D ). All mention of road or MTB / gravel has been dropped. New Motion Labs.

One thing that appears to be a pro that is not listed is that they rate the "downshift" to the 0.7 ratio is rated up to 1000W so, unless you have monster thighs and quads, you can down shift even while standing up, and that happens very quickly. Is that worth the efficiency lost? Maybe under certain scenarios, but probably not.

In the real world, the benefit of lower chain tension essentially gets balanced out by the disbenefit of faster chain speed. Running larger sprockets does result in one benefit of lowering polygonal losses (oscillations in chain speed due to chordal action), although really these losses only become significant when running sprockets smaller than 14T.

It’s a beautiful design, can’t argue with that. I could see a use case with more performance focused e-bikes which have electric crank drive motors, gravel, mountain e-bikes etc. The efficiency of the chain is quite amazing and the engineering / precision in modern derailleur gears is quite staggering, hard to beat with anything.

You omitted the biggest plus, which is ability to shift under load. I agree with you that their only chance of success is to be integrated (I.e. acquired or licensed) with SRAM (since they seem more interested in 1x than Shimano. This tech is better for gravel and MTB - since Road racers will never be able to do quick wheel change with neutral Shimano service vehicle.

Really love this video. Can you do another one with more detail? you mention it very briefly, but can you do a more in-depth analysis and comparison with the drop of efficiency with cross chaining? Also if you only have 1x in front, don't you get worse cross chaining since nobody would mix the small chainring with the smallest sprocket? meaning classified would actually have more cross chaining than a standard front derailleur.

Hammerschmidt was somehow simpler and put the extra weight in the chainring instead. It seemed to vanish all the same, though

Classic case of a solution looking for a problem where there is none. This will never work as adoption hurdle far too high. Another great video.

It's an interesting concept, but I wouldn't be inclined to try it based on the loss in efficiency. I noted one of your points related to wheel changes. If the transmitter is attached to the through-axle, it may not be a big deal as long as the through-axle remains with the bike and there has been some prior syncing with the new wheel components.

It is a clever idea and would work really well with crank based E-bikes motor such as the Specialized Creo, where 2x is not an option. The cost is bonkers and the serviceability do put ne right off.

I have a still working Hammerschmidt crank and when you are on the geared side of things there is noticeable drag. This is on a mountainbike , just the design of these systems means there is going to be internal losses .

That actually looks like an Edco mono-block cassette. They are about 200.00 US. I use one on my training bike, they work well.

To me, the cassette is a custom cassette made by Harryrecon, the Shimano/campa/SRAM version is sold in Europe by E.dubied. I mean, I have one of them for my wheels, it is made of steel and it is superlight

It's not comparable, but isn't the small ring also a slight mechanical disadvantage of a % or so? With chain wrap and articulation?

I would guess you could check out the efficiency by running the following test. Have 2 models of the same bike, 1 normal 2x and one 1x with the Classified hub. Run each of them on a cycling treadmill with the same rider riding both bikes, same tyres and tyre pressure, at a standard wattage of say 250 watts measured at the cranks or pedals. You would then be able to see the different speeds and wattages on the treadmill compared to crank watts measurements. This could also be checked in different chainring combinations on the 2x bike to see if that makes a difference.

Regarding the inertia and acceleration: I think you have to consider that the low distance to the center of rotation compared with the rim of a wheel means it will be significantly less noticeable than if you had a heavy set of wheels. Certainly for the average rider they will likely not notice any difference, ditto with the efficiency loss. For a road bike this seems to make less sense than for a gravel bike. A lot of gravel riders are already running a 1x setup, this would effectively just give them closer gear spacing or an even wider gear range depending on setup. It's also less problematic than a front mech, especially for quickly changing gears or with regards to reliability and durability in off road situations. I think your conclusion is correct for road bikes, but for gravel or even perhaps MTBs, there's a place for this system.

I still use a SRAM DualDrive II which is kind of a 3 speed internal hub + 8/9 speed cassette.

Peak Torque gave what appears to be a realistic review of the hub. The efficiency claims appear to be close to Classified's. Please note I use "appear/s".

One aspect I was considering was that... if you used it for an aero setup... then using the 'lower ring' ie.. with the lossy planetary gears engaged.... might not actually be used.... or used so little, that the 'losses' don't overcome it's virtues. An expensive 'solution' is given... perhaps it IS, potentially, the expensive 'solution' for a very specific problem.

Such a major improvement over the 1950's 3 speed hubs (Shimano, BSA, Sturmey-Archer ...) 🤣 maybe they keep their 3rd speed... classified ?

I think a similar combination of hub gear and cassette was tried before. I think it was Sachs, but it was also the late 80's so any detail escapes me now.

I’d like to see Froome’s mechanics deal with this after the disc brakes an wheel changes have been solved. My tuppence worth is that it’s too expensive and annoying for me. I’m happy with cables and a front deraliur.

There is a option to pair it to the Di2 / ETap levers which means no additional switch needed. You just shift as usual. But from what I heard the reprogramming is a one way street. No going back to using your Di2 as a 2x setup as before.

I think it looks interesting for a gravel or a road bike. Is the 4% that big a deal for a 'bailout' gear? I ride almost exclusively in the big ring ( it is a 50 though but I do live in the lake District) and if it gets steep enough for me to be in the 34 then I'm probably out of the saddle. It does have full integration with last gen Di2 and GRX, I'm seriously considering it, maybe try it on my gravel bike and see how it works out. I did try a hammersmidt thing years ago on an MTB which is similar tech on the crank. You could definitely feel it in the low range taking a bit of power but it was no big deal.

this can be unnecessary for road bikes but it is a HUGE upgrade for MTB especially for XC/enduro bikes, we can climb up punchy/techy/loose sections without needing to install a 50 tooth cassette AND STILL retain that critical 1x setup for mtb. this would mean easier/balanced control on the rear end when doing berms/jumps/tailwhips whilst improving the RD shifting performance because of the smaller transition between the (now-smaller) easy cogs of the cassette. if they'll bring the cost down this would explode like dropper posts did.

Very accurate explain. Nice

I hoped it could be used in my velomobile to reduce the gearing further instead of having a third ring or a gearbox like the Moutain Drive, or a Pinion in the front but the losses are a no go compared to a chain only since with velomobile riding effiency is everything.

I see this being pushed onto, or more readily adopted by, gravel bikes. Manufacturers are seemingly competing to see who can fit the widest tires on gravel bikes. A lot of gravel bikes are 1x only as a result. But, a lot of people want smaller jumps in gears but lots of range. This seemingly "fixes" that problem. I could see it being successful on gravel bikes and with recreational riders.

Constantly innovating and moving away from tried and tested pleasures may prove excessive but worth a try … such gearing on a Brompton around tow makes for quick acceleration from standing start …

How much better would this be compared to the holy grail of hub gears (rolhoff)? Would you be better off adding a few more gears while you're at it?

Agree with your main point about this, it just doesn’t make sense for “serious” road bike use which is what it’s pitched at. A question though - mountain bikes went to single chainwheel a long time ago and manage with a bigger difference in rear cogs. Wouldn’t that be possible on a racer? Sure there will be chain tension issues but overall surely still better than a gearbox.

I’m skeptic but interested to see how this all plays out. However, when I read about people dismissing 2x setups as if they’re the worst thing to have on their bike, I feel like an alien. People really willing to pay the cost of DT efficiency, increased complexity and $900 to remove their front mech and chainring? absurd

I've followed the adverts about this thing since it first became public. Once it became available here in the US I inquired about the price. It will cost you $3400 to have this system put on your bike. Is that that a number you're willing to pay just to drop the front mech and one chainring? IMO this gear system should not have gotten this far and should be gone already. Thanks Hambini for you comments and pointing out more industry BS.

I think you should consider getting building an rig to measure efficiency. Also to get data for crosschaining. I suppose you could attach an electric motor to the chainring

Good analysis, thanks.

Dura Ace is closer to 98-98.5% efficiency. So you actually loosing more. Everyone is trying to re-invent the wheel with regards to bike drivetrains. 1Xs, classified hub, ceramic speed shaft drive. Yet Noone realises we actually struck gold 100 years ago and there is really no reason to fix what ain't broke. 2X MTB master race right here!

It would be the perfect buy for SRAM as their Front Derailleurs' are pants and need very careful setting up. Or if they can come up with a solution to integrate into Sram eTAP, Shimano DI and Campag EPS control systems. But given the power loss it may suffer the same fate as other hub gear systems and be for town/commuter use, in which case it will be prohibitively expensive I guess.

A 1x drivetrain is less efficient due to the smaller front ring. This loss of efficiency needs to be factored in when comparing the small ring on a 2x to the Classified hub. Looking forward to seeing some independent testing

Campanaerts said that the shifter is callibrated to the thru-axle so in the race he just had soigneurs around the course and neutral service cars with spare wheels and as long as he kept the same thru-axle there wouldn't be a problem with that.

Switching to a 1x chainring will also add more friction to the drivetrain. I wonder how it would work when added to a 2x drivetrain? You don't necessarily have to get rid of the front derailleur and use a big cassette. MTBing may have an use for it because there is no other options to increase gear range.

I haven't got one but a riding buddy has, he said the shifting wasn't "bad" with a Shimano chain but it wasn't great either. He swapped to a SRAM and it improved "a lot, maybe 95% to Shimano quality" Not surprising really SRAM chains have always been the go to when mixing drivetrains/using aftermarket cassettes, and I guess with no front mech' to worry about and a NW chainring you only need a chain that plays nice with the cassette. He's 11 speed though, not sure how well that would workout with HG+ and Flattop chains I suppose SRAM Eagle?

Could this be a first step towards ebike applications where a 4% efficiency loss doesn't matter as much?