German upstart Qvist puts an ingenious spin on the classic star ratchet hub
German upstart Qvist puts an ingenious spin on the classic star ratchet hub
DT Swiss-style star ratchets have become increasingly widespread in recent years now that the company’s patent has apparently expired. Not surprisingly, copycat designs still differ only minimally from the original concept, offering presumably excellent durability, but also the same limitations on engagement speed. However, German upstart brand Qvist — hailing from the Saxony region — has taken the star ratchet idea and applied a genuinely novel take on the idea that hopefully retains durability while drastically improving engagement speed.
Qvist is using a conventional star ratchet design, but there are actually two of them working in tandem, stacked on top of each other inside the oversized aluminum hub shell, and with the center ratchet sporting teeth on both faces. Each pair of ratchets has 64 teeth, but because each set is out of phase with the other, there are effectively 128 points of engagement. In this way, Qvist says you get the durability benefits of larger ratchet teeth, but also a hyper-quick sub-3° engagement speed that usually only comes with systems built with much finer ratchets.
Looking at Qvist’s “double ratchet” physical layout, it’s actually sort of a hybrid of the Chris King RingDrive and DT Swiss’s latest Ratchet EXP. Like RingDrive, the machined aluminum freehub body features a long extension on the inboard side where all of the ratcheting bits reside. There’s a disc-like snap ring on the inner end, and a single coil spring that pushes everything together.
Like Ratchet EXP, one ratchet ring is fixed in place and doesn’t move during normal operation, while the one at the other end slides axially as you coast. In between is the third ratchet ring that not only floats in between the other two ratchets, but also is responsible for applying torque to the drive shell.
Because all of the driver guts live well inboard of the freehub body, Qvist is able to use an enormous main bearing on the driveside of the hub shell, while the innermost freehub body offers more support for the oversized aluminum axle than usual since it’s located so far near the centerline of the hub. And since the main bearing then shields the driver guts from the elements, Qvist can lubricate the system with oil instead of grease, which should not only provide snappier operation, but also potentially reduce friction.
Currently, the three ratchet rings are machined from stainless steel, while nearly everything else is aluminum. According to Qvist, the whole thing is very easy to service despite the perceived complexity, and all of the bearings are standard sizes and configurations that are easy to source and replace if and when needed.
Weights are quite competitive, too, with the front hub coming in at 145 g and the rear tipping scales at 270 g with a SRAM XD freehub body.
As impressive as the Qvist hub design looks at the moment, I do have have a couple of concerns. I’d like to see a supplemental seal to protect the main bearing from contamination (the single seals on cartridge bearings are almost never sufficient to survive real-world conditions), and given how the driver mechanism includes two stainless steel ratchet rings sliding continuously on aluminum splines, I wonder how this will wear over time.
Qvist doesn’t think that sort of wear will be a problem, though, and since the hubs aren’t yet in production, there are still some details being finalized. Pricing is still being finalized, too, although Qvist aims to keep figures competitive with other higher-end options despite committing to German production.
However these end up, it’s an ingeniously simple and clever take on proven concepts. Qvist is hoping to have these available for purchase some time in 2023 — and I’ll be eagerly awaiting the opportunity to give these a go.
More information can be found at www.qvist.cc, and more coverage of our coverage from the 2022 Eurobike show can be found here.
