36-Tooth One-By Chainrings

Posted by: Jan Heine Category: Uncategorized

36-Tooth One-By Chainrings

The new 36-tooth one-by chainrings for Rene Herse cranks are now in stock. Like all our components, they’ve been tested extensively before we offer them to our customers. We’ve run them on challenging courses with different drivetrains to make sure they are compatible. Above is Anton Krupicka, who rode a prototype in this year’s Unbound XL 350-mile gravel race.

Anton ran a 12-speed SRAM Force drivetrain. He reported: “My drivetrain was pretty much flawless through the race (except for the extreme mud section, of course, in the last 30 miles), even when there were SO MANY noisy, grinding drivetrains around me through much of the night.”

By the way, Anton placed 17th in a very strong field of professional riders. Well done!

Mark Vande Kamp, who ran a 40-tooth one-by with the new SRAM Red XPLR 12-speed electronic drivetrain, also had a trouble-free run in Unbound XL, despite difficult conditions—not just multiple creek crossings, but also deep and sticky mud that Anton alluded to in his report.

What makes the Rene Herse one-by cranks special? The tooth profile has been developed through computer modeling and on-the-road testing to mesh perfectly with the chain. It looks deceptively simple, but there’s a lot going on. Obviously, every second tooth is thicker to mesh perfectly with the outer link of the chain. This keeps the chain running smoothly when the chain angle is extreme in the highest and lowest gears of the rear cassette. Otherwise, the chain would come off every time you hit a bump while riding in those gears. (On double or triple cranks, the front derailleur also acts as a chain guide that keeps the chain from falling off.) The tooth profiles themselves are fundamentally different from those for double/triple chainrings. There is no need for shifting, so the teeth are optimized for chain retention.

Like all Rene Herse chainrings, the one-by versions are made from ultra-hard 7075 aluminum for the ultimate wear resistance. The material is only one reason why our chainrings last so long—I’ve ridden my first set for more than 20,000 miles without any apparent wear. Thanks to ultra-high-precision machining, the teeth mesh perfectly with the chain, which also reduces wear (both of the ring and the chain).

We like to design our parts so they are upgradeable and compatible across generations. Our one-by cranks are available in two versions: You can either choose arms that are specific to single chainrings—the lightest and most elegant version—or you can select double/triple arms with special spacers that go where the second chainring usually sits (shown above). This means you can swap to a double (or even triple) in the future without needing new cranks.

The spacers are also available separately, so you can convert any Rene Herse crank to a one-by (and vice versa). It’s all part of our commitment to creating parts that are durable, serviceable and upgradeable.

All Rene Herse cranks are net-shape forged for superior strength and ultralight weight. They pass the most stringent EN ‘Racing Bike’ standards.

Originally, we introduced the one-by cranks with 40-tooth chainrings. That’s a great size if you use 650B or 26″ wheels (above) and ride with a light load, but for larger wheels and/or bikepacking, the gearing is taller than most riders need. So we’re now also offering 36-tooth chainrings.

Both chainring sizes and all arm lengths are in stock now. Choose between one-by specific arms or keep your options open with arms that are convertible to double/triple. Head to our online catalogue for more information.

Photo credits: Linda Guerrette (Photos 1, 2); Anton Krupicka (Photo 3); Mark Vande Kamp (Photo 6).

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