Rene Herse Cranks with Downshift TechnologyJan Heine
The wait is finally over: Rene Herse chainrings are coming off the production line again. But this is more than a ‘Back in Stock’ notice: The new chainrings feature our downshift technology. This technology is found on the very best 12-speed chainrings (including those from Rene Herse), but this is the first time it’s been applied to classic rings that work in any chainring combination.
First in line are 46-tooth chainrings. Why did it take so long? Aluminum shortages have been a problem for the past two years. You can’t just use any 7075 aluminum for Rene Herse chainrings… For the same reasons that make our cranks so light and versatile (only three arms, small bolt circle), our chainrings need to be made to much tighter tolerances than other rings. This means only the very best aluminum sheet—without any inbuilt stresses—can be used to make Rene Herse chainrings. It was frustrating to make prototype after prototype, before rejecting yet another batch of aluminum, but we finally have the material we need.
We’ve used the wait to redesign our standard chainrings with our downshift technology. When we developed our 12-speed-compatible chainrings over a 2-year period of intensive R&D, we worked on ramps and pins for upshifts that rival the best in the industry. We also looked at downshifts, because those are actually more difficult, especially with the large differences in ring sizes that many of us run. Take Natsuko, for example: She runs a 42×24. That means her small ring is only 57% the size of her big ring. Compare that to 68% for a 53×36, the most extreme you’ll find on racing bikes.
The large drop means that the chain has to fall at exactly the right angle, otherwise, it can derail. It’s not like Natsuko’s chain actually fell off, but the drop to the small ring didn’t feel smooth.
As an experiment, we mounted a 42/26 12-speed chainring on Natsuko’s bike, even though the upshift ramps don’t work with her 24-tooth chainring. (Upshift ramps rely on a defined chain path, so they work only with dedicated pairs of rings.) Natsuko reported much-improved downshifts. “Finally I can just shift, and not worry about the chain falling off,” she exclaimed.
That got us thinking: The downshift tooth shapes work by letting the chain pass through without having to climb over the tops of the teeth. This doesn’t require dedicated pairs of chainrings. That’s why it works even when we’re running an ‘incorrect’ chainring combo. What if we incorporated this downshift technology into all our large chainrings? That way, the hardest part of shifting would be greatly improved for all users—without giving up the ability to freely combine chainrings.
To test this idea, I ran a 42-tooth prototype ring with the downshift technology on my bike during the Oregon Outback and Unbound XL. Conditions were really tough in both events, with hundreds of front shifts while riding through dust, river crossings that washed off the chain lube, and mud. The shifting was great—showing that the technology works with all kinds of chains (Natsuko runs 11-speed; I have a 7/8-speed chain) and in all kinds of conditions.
As an added plus, the new tooth shape further reduces the risk of chainsuck, even when the chain is squeaky dry and covered in dust during long bikepacking adventures.
While we waited for the right material, we redesigned all our large chainrings with the new technology. The new 46H is already in stock. This also means that we can finally ship cranks again. Other chainring sizes will follow. Our 12-speed-compatible chainring with their amazing shifting performance are also in production. But first we’ll have another long-awaited item: 36-tooth One-By rings. Stay tuned!
Click here for more information about Rene Herse cranks.
Photo credits: Rugile Kaladyte (Photo 1)
Note: The product photo of the cranks still shows the older chainrings without the downshift technology.