Whenever gearboxes or gear hubs are mentioned it becomes clear there are a lot of gearbox fans out there, and it's easy to see why - derailleurs are finicky, vulnerable and unreliable. But there are a few good reasons derailleurs still dominate over gearboxes: weight, compatibility, shifter ergonomics and drivetrain efficiency. Kindernay's gear hubs appear to solve some of these issues.
Kindernay is an engineering company that has developed hydraulic gear shift systems trucks, so they should know a thing or two about building gearboxes. Alongside hubs for commuter bikes and fat bikes, the company has two gear hubs that could appeal to mountain bikers: the XIV and the brand new VII. Both are available with 12x148mm and 12x142mm axles and could be fitted to most bikes, including ebikes.
Fans of Roman numerals will have guessed the XIV offers fourteen gears and the VII has seven. The XIV has a massive 543% gearing range, with consistent 13.9% gaps between gear ratios - no single-ring derailleur system can match that. It costs €1,249.92. Meanwhile, the new VII has a gear range of 428% (similar to a 10-42t 11-speed cassette) over 7 speeds, with meaty 28% intervals between gear ratios. Unfortunately, it's OEM only for now. Both use a pretty interesting hydraulic shifting mechanism and interchangeable "swap cages" which allow one hub to be used on multiple bikes. Weight
Perhaps the most important downside of gearboxes is the weight. And unlike frame-mounted gearboxes, the mass of a gear hub is unsprung, meaning it has to move up and down with the suspension, so suspension performance suffers. The Kindernay XIV has a claimed weight of 1,400g for the hub alone, while the VII weighs 1,200g. For comparison, a Rohloff Speedhub weighs about 1,545g for the raw hub.
The weight of the VII isn't too far off the weight of a conventional hub, cassette and derailleur combined - a DT Swiss 350 rear hub weighs 270g, a Shimano Deore 12-speed cassette weighs 593g and the derailleur weighs 318g, which adds up to 1,181g. So the XIV gear hub is in the same ballpark as a "workhorse" 12-speed derailleur drivetrain.
There's also the swap cage (more on that later) which weighs around 100g, the hydraulic connector for the shifting, a sprocket, plus you'll need a chain tensioner, but we're still only talking about a few hundred grams more unsprung mass over a budget derailleur drivetrain. The total unsprung mass at the rear wheel is typically 3-4 Kg, so this is in the neighbourhood of a 10% increase.
The claimed total system weight is 1,750g. A standard shifter and cable weigh around 200g, so added to the hub, cassette and derailleur the comparable conventional setup would weigh around 1,381g. That means a total weight penalty of about 369g compared to Deore 12-speed.Shifting
Most gearboxes need two cables to operate the shifting; that means they often require a grip shift, which isn't ideal for mountain biking. Kindernay's gear hubs use a pair of hydraulic hoses to operate the shifting and a conventional-looking under-bar shifter with thumb shift levers. By the looks of it, that should be more familiar to most mountain bikers and it allows you to use normal grips. Kindernay call this shifter the Onesie
; there is also the option of the Twosie
, which splits the hoses so the upshift is on one side of the bar and the downshift on the other, but most mountain bikers with dropper remotes will go for the Onesie.
While gearboxes don't like to shift while pedalling hard, these hubs can shift multiple gears at once without pedalling.Compatability
While frame-mounted gearboxes only work with frames designed to accommodate them, one advantage of gear hubs is they work with normal frames. But fitting a gear hub involves lacing it to a rim, and if you want to swap the hub to a different bike you may need to re-build the wheel with a different rim. Kindernay offers their hubs with interchangeable swap cages which alleviate this problem. The cage is laced to a rim and the hub can quickly be detached from this and installed onto another swap cage/wheel. This makes it possible to share a hub between multiple bikes or keep the hub when you change your bike. Of course, this isn't as simple as fitting a new derailleur or cassette, but it should make the gear hub easier to live with.Thoughts
While the VII only offers seven speeds, the gearing range should be enough for most people. Fewer gears mean less weight and the VII isn't all that far off the weight of some derailleur drivetrains. Yes, it's still heavier, but not by an amount that should keep anyone up at night. Drivetrain drag and the inability to shift under load are still huge drawbacks of many gearbox systems and I don't know how Kindernay's hubs stack up on those fronts, but the swap cage system and shifter design look promising. It would be interesting to see it fitted to some rugged bike-packing bike where reliability is king.
Is it still too heavy? Are seven gears enough? Let us know what you think in the comments.