Sun and planet gears, proprietary internals, electronic signals, and precise shifting under load. Those are just some of the topics that John will walk us through in his Classified Powershift Hub for mountain bikes review below…
Proprietary and electronic are two triggering words for many cyclists, especially in an era where cable-actuated drivetrains are going the way of the dinosaurs. All it takes is one quick look inside the comments here on The Radavist in any tech announcement post to read honest opinions regarding new tech. I don’t disagree with these opinions, yet if I find myself intrigued by a piece of tech, by all means, I’m going to try it out…
At the 2023 MADE show, I chatted with the Classified Cycling team, a company offering a wide-range hub system that requires no special drivetrain or gearbox to deliver a ~70% gearing reduction. Instead, the Classified system is contained in a single hub. In this case, a single MTB, boost-spaced hub. One you can lace to any wheel from 26″ to 29″, as long as your frame is boost spaced.
If you have a non-boost spaced frame, Classified makes a Gravel Powershift hub.
Products like this might not apply to my, or your, day-to-day use case, but the fact that they exist is almost a requisite for me to try them out. So before we get into the nitty-gritty, let’s look at some possible scenarios where I feel the readers of The Radavist could apply this tech.
The Powershift hub shell and the 12-speed 11-40 cassette…
Quick Hits
- Wheelset with System: $3,199 (as reviewed here)
System without wheelset (for partner wheels): $1,499
System with Shell without wheelset (for wheel builders): $1,599 - Boost-spaced hub
- 150 milliseconds shifting (impossible to test as a Luddite)
- Allows for real rider power with 1000 watts load shifting max
- Up to 530% Range
- Smaller gear steps
- Electronic thumb shifter and Bluetooth thru-axle shifter
- Weatherproof – fine for riding in pouring rains, monsoons, etc. (best not to fully submerge in water, though…)
Available cassettes:
- 13 Speed: 11 – 36 (Campagnolo Ekar for the Classified gravel hub)
- 12 Speed: 11-28/ 11-30/ 11-32/ 11-34/ 11-40
- 11 Speed: 11-27/ 11-30/ 11-32/ 11-34
Classified Powershift Hub Use Case Applications
Modern mountain bikes, at least a majority of them being mass-produced today, are incompatible with 2x or 3x drivetrains. There are a few reasons for this. First, it’s worth pointing out that major component manufacturers have largely moved away from the front derailleur in favor of wide-range 1x setups.
Now onto the chassis design of modern mountain bikes. Boost frames allow for a fat tire to be slammed close to the seat tube, interfering with potential derailleur mounting space (i.e., a tire, seat tube, and chainring take up too much space with shorter rear ends. As such, 1×12 drivetrains have proliferated in the MTB and drop-bar MTB or touring bike space).
Yet, these “knuckle dragger,” long-cage derailleurs are quite polarizing for many people. I’ve seen it brought up in countless forums:”Your derailleur is going to hit a rock and end your ride;” “That knuckle-dragging rear mech looks horrible on that small-wheeled bike;” etc.
Now, I take this sort of commentary with a grain of salt because in the 10+ years of 1x proliferation and throughout my personal experience, I have never, ever, ever once hit my mech on a rock where the impact resulted in a broken rear derailleur. Ever. And I ride mostly in steep and rocky terrain. This paranoia reminds me of the derailleur guards some people rode with in the 1990s. People, it’s a bike. If you don’t baby your gear, it will get banged up on rocks. A long cage derailleur doesn’t mean it’s an Achilles.
Anyway… Using something like the Classified hub system, people could use a medium cage rear mech—and avoid using a long cage, 12-speed derailleur—and still get a massive gear spread of up to 530%. We’ll get to how and why in a little bit.
Many cyclists also like tighter shifting steps, one thing that has gone away with the advent of 1x drivetrains. The Classified hub expands your gear range and provides much closer shifting steps. In many ways, it’s very similar to a 2x drivetrain, but in more ways, it’s not.
Cargo bikes and touring bikes are another, more obvious, use-case scenario for a 70% reduction hub system like Classified. If you have a pedal-powered, non-e-assist cargo bike, say for trail work, grocery or kiddo gettin’, or doggie haulin’, it’s nice to have a bail-out gear to reduce those gear inches to a favorable cadence and power output.
On a bike like a drop-bar MTB or boost-spaced touring bike that you use for gravel riding, it’d also make a ton of sense. That way, you could have a 1x setup with 100% gearing for unloaded rides and drop it down, when needed, to the 70% gearing when you’re loaded down.
If you’re still unsure how this system works, let me break it down…
Please excuse this rudimentary illustration… ;-)
How it Works: In Layman’s
Classified’s hub is ingenious and is based on a two-part hub body. The hub shell appears to be pretty innocuous. It looks like a normal MTB hub with its internals missing. Then there’s a carrier body, which is like a large ring gear. That’s where all the magic happens. This locks into the hub when you assemble it.
Inside this carrier assembly are two axle shafts. The first is locked into place with a “sun gear.” This looks like a gear attached to the main axle shaft via a needle bearing with a one-way clutch. The sun gear spins in one direction on this axle.
Then, a secondary axle and carrier support six “planet gears” inside a ring gear. Together, the planet gears and sun gear assemblage spin when the Classified hub is locked together in the 1:1 gear range.
To drop into the 70% reduction gearing, the planet gears disengage from the sun gear, and since the sun gear is on a one-way needle bearing/clutch, the sun gear locks to the hub carrier, and the planet gears spin around it at a reduced gear with the cassette.
So, when you are in a 1:1 gearing setup, the entire gear carrier is attached and spins together. When you switch to *70%, the planet carrier is disconnected from the ring gear.
At this point, the planet gears want to make the sun gear rotate in the opposite direction, which is prevented by the one-way bearing supporting the sun gear. The sun gear is thus locked down to its axle and the planet gears (and thus planet carrier/ring gear) rotate around the sun gear at a velocity that is determined by the tooth numbers of the planetary gear system.
*Technically, the reduction is 68.6%, but for simplifying this complex system for review, I rounded up to ~70%. You could roughly compare this to the ratio between a 36T and a 54T chainring or a 34T and a 50T chainring in traditional 2x systems.
The proprietary thru-axle keeps the carrier body in tension within the hub shell. A special torque arm (above photo) rests on your bike’s chainstay to brace against that one-way needle-bearing clutch when you shift down to the 70% reduction gear. The signal to unlock or lock the carrier body is sent via Bluetooth by a shifter module mounted to the handlebar and charged via a USB plug.
The system is genius. In comparing the Powershift Hub with a traditional hub, when the system is in its 1:1 ratio, only three bearings are “active” and in motion, whereas traditional hubs have four bearings rotating.
This oversimplifies how a complex system works, but that’s the gist for this review’s sake. It’s very similar to a transfer case in a 4WD vehicle. The quick takeaway is that you can achieve up to a 530% gear range with smaller steps, depending on your drivetrain. If you’d like to get the most out of the system, you can increase your chainring by 10%. I opted to keep my 28t for this review but could have gone up to a 32t.
For those interested in efficiency data, Classified has this snippet on its site:
“Drawing on our experience in the automotive industry, Classified tested the Powershift hub to the highest standards, using a test rig specifically designed to measure power loss with a maximum error of 0.1%. The results of these tests show that the hub is 99.8% efficient in the 1:1 ratio, the same as a DT Swiss 240 hub (industry standard) measured on the same test rig, and 99.2% efficient in the 0.7 ratio, making it the most efficient internally geared hub ever created.”
Weight Comparison
When I mention that I’m reviewing the Classified hub to other cyclists, they usually reply with a query:
“Yeah, that looks cool, but isn’t it heavy?”
To be honest, I usually leave weighing components until the very end of the review period and base my review on my experience rather than metrics like weight. After the riding period, I weighed my standard rear wheel against the weight of the Classified Powershift rear wheel. I took off the rotors and tires on both wheels but left the valve cores, rim strips, and cassettes on.
My Chris King rear wheel, which also features a carbon fiber rear rim, Chris King mountain hub, and a SRAM XO1 10-52t cassette, weighs 3 lbs, or 1360.7 grams, on the nose.
The Classified Powershift rear wheel, which is also a carbon fiber rim, and a 11-40t cassette weighs in at 3 lbs 2 oz, or 1417.45 grams. A mere 2 oz is not at all what I was imagining. Weight is not a concern here.
Chris King MTB Hub and Chris King Carbon Rim = 1360.7 grams
Classified Powershift Hub and Classified Carbon Rim = 1417.45 grams
Some Assembly Required
When you receive the Classified hub or Classified wheel, there are a few small boxes containing parts, a cassette cluster, a carrier assembly, a proprietary thru-axle with spacers, and a QR code for installation instructions.
The setup is pretty straightforward.
I used my Moots Womble as a test mule for a few reasons: it’s a US-made, small batch frame presenting a few unique frame details that would challenge the Classified’s “universal” fitment procedure. If you have a bike from a large manufacturer, Classified has a specific thru-axle fitment kit for you.
To select the appropriate kit, you simply find your bike in the drop-down menus. It’s also the bike I have ridden the most in my current stable, so nuances in the riding experience would be more noticeable. And it has SRAM AXS, which shifts the cleanest and sharpest out of all my bikes, making the Classified experience even more pronounced.
The Womble is not on the drop-down menu lists for easy compatibility specs and utilizes “hooded” dropouts, which require a hodge-podge of spacers and threaded ends to get the correct fitment. It was very straightforward, and due to the thru-axle’s modularity, I was able to procure one of the universal fit kits and get the bike rolling easily. The Classified thru-axle allows you to swap out the threaded end of the axle to achieve more or less threading, depending on your bike.
This process is simplified by using an authorized Classified retailer. :-)
Exploded diagram provided by Classified
Once the entire kit was assembled, I paired the shifter with the thru-axle, charged the system once, and used it for two months before I charged it again. I had no indication that the batteries needed charging, I just felt like two months of use was a good time to top them off. Keep in mind, if your thru-axle battery dies, it doesn’t render the entire bike or derailleur unusable. It just keeps you from shifting into or out of the 70% reduction gearing.
Experiences While Using the Classified Powershift Hub
My intention here is not to sell you on this product or laud its accomplishments but to explain how it functions.
I’ve ridden both a Rohloff and a Pinion in the past. Never for months or years like many devoted owners, but enough to get the “feel” of them: a few rides, etc. With both systems, there is a spongy feel to the shifting; it is like the shift is damped. When you shift a Rohloff or a Pinion, there is a moment where the engagement feels soft. I’m sure this hesitancy is reduced upon habituation, but it is jarring upon the first few pedals.
With the Classified hub, there is no such lag. None whatsoever because you are utilizing a 1:1 and 70% gearing shift (i.e., the feel of the 1:1 shifting is all dependent upon your derailleur since the cassette is a single-piece, milled steel construction).
Then, the shifting disengages the sun and planet gears, and the 70% reduction comes from the planet gears spinning around the sun gear. When that shifting or disengagement happens, it can occur completely under load with a flawless transition. It’s barely noticeable, aside from your increase or decrease in pedaling cadence. It’s marvelous.
You can be punching up a steep and loose climb, in or out of the saddle, and then shift the ring-shifter on your handlebar, and the 70% reduction happens instantaneously without hiccup or hesitation. It’s smoother than the AXS derailleur itself!
That perhaps brings up an interesting point: the Classified hub’s performance is entirely up to your endemic drivetrain. I found the Classified cassette mated perfectly with the SRAM AXS 12-speed drivetrain. For the sake of more thorough testing, I swapped out my used chain and chainring for a brand new pair and didn’t notice a difference, or at least not one worth noting.
If your goal is to have a 70% reduced drivetrain available at the flick of your thumb, there is no system better than the Classified Powershift Hub.
However, In the interest of complete transparency, I did break the rear wheel on what I would consider a casual ride on some rocky singletrack while I was in Las Cruces on a pedal with Matt Mason. I bump-jumped a rock and landed on a flat section of trail, causing the wheel to make a loud “pop.” Within seconds, the tire was flat, and it was evident I had broken the wheel. Matt even commented on how non-consequential the jump looked.
I shipped the wheel back to Classified, and they sent me a new one to continue this review. Now, Classified is in the process of producing a more robust rim design, as this wheel was intended for “XC riding.” And carbon wheels break all the time. However, I have never had a wheel break like this on my mountain bike. As such, it’s my recommendation to build these hubs to rims of your choice…
Be mindful, though as Classified has a use case disclaimer:
“The Classified Powershift 148 hub is intended for cross-country mountain biking and light trail riding only. It is not suitable for enduro riding. Misuse may result in damage, accidents, or injury. Please use as intended and assume all associated risks.”
Some Notes to Consider and Ponder
Yes, you have to charge the Classified system. BOTH at the shifter and at the thru-axle. There is a proprietary charger at the handlebar trigger, so if you lose this charger or break it, you will have to order a new one from Classified. Luckily, the thru-axle charger is a standard USB 2 cable.
The proprietary game doesn’t end there. When the cassette wears out, you’ll have to order a new one from Classified. This is something to consider if you’re planning on taking this system on an extended tour.
To reduce the proprietary nature of its product, I wonder if Classified would or could license this technology to hub and cassette manufacturers. DT Swiss, Industry Nine, Chris King, et al., would and could benefit from adopting this system. Then, it wouldn’t be potentially bottle-necked for one manufacturer to keep up with if this system becomes more commonplace. Edit: it seems Spinery did just that!
Tech Advancements for Self-Inflicted Injuries
I like to contextualize the bicycles I talk about here on The Radavist. That’s why we invest so much time and money in our Vintage Bicycles category! It’s important to look at where the mountain bike came from to understand where we are today and where, ultimately, it could go. We try to steer the site’s content according to how we feel the sport ought to be showcased.
Looking at the condensed history of MTB cranksets above and the meme I drew up, I can’t help but point out the ironic bed we’ve made. I’m certainly guilty of supporting this march to the “…” era illustrated above, yet I do feel like it is honorable for Classified to design a whole new system like Powershift.
Personally, I love the 1x 12-speed drivetrains on my mountain bikes. I don’t particularly miss a 2x drivetrain, nor am I one to complain about the large gearing steps people lament about so often in forums and comment sections. For me, a mountain bike I ride on trails is best when it’s operating efficiently with a 1x system. Mountain biking is inherently a more risky form of cycling. While I’m riding I want shifting to be simple and secure. I don’t think a front derailleur necessarily needs to be a part of trail riding. For me, anyway.
Yet, I do find that in certain applications, a 2x drivetrain makes sense, and thus, a Classified Powershift system makes sense. Namely mixed-terrain riding and touring. If I were building a drop-bar touring bike or a rigid MTB for touring, I would use a Classified Powershift hub if I couldn’t fit a 2x drivetrain on the bike. If I wanted to build a bike that would be ridden on fire roads and double track primarily, a 2x or 3x drivetrain would also make a lot of sense, as would a Powershift system.
Perhaps that’s why I feel like the Classified Powershift Gravel hub is the real crowning achievement in the brand’s catalog. Does it have a better-suited use case for more riders?
Nothing shifts as crisply under load, not even XTR Di2 or Sram’s AXS platform. Classified’s fluidity and efficiency are what make it so unique. It’s not spongy or soft feeling like Pinion and Rohloff systems can be.
That said, it is not without nuances: proprietary parts and batteries that need charging, albeit infrequently. As with all cycling tech, it’s a system of compromises, and it’s up to you to determine if the Powershift hub falls within your use case.
Pros
- Shifts super smoothly
- Batteries didn’t need to be charged over a two-month review period
- The weight difference is negligible at 2 oz heavier than a comparable wheel
- Works on your existing drivetrain
- Very efficient
- Offers a whopping 70% reduction!
- Lots of “fit kits” to get it working correctly on your bike
- Extremely weatherproof (this hub was developed in Belgium after all!)
Cons
- Proprietary parts
- Batteries that need charging
- Expensive
- Setup can be tedious if you have a custom or non-mass-produced frame
What are your thoughts? Is a system like Classified’s Powershift hub relevant in today’s 1x-dominated world? Let us know in the comments. Thanks to Bailey at Sincere Cycles for the assistance in building the system up!
See more at Classified.