When it comes to drivetrain innovation, it’s easy to assume the big players have it all figured out. Oval rings, narrow-wide teeth, optimized offsets—it feels like every shape has been tried. But every so often, someone outside the mainstream takes a shot at rethinking the fundamentals. That’s where Doug Brown Jr. steps in with his Spreng Reng project.
This is no garage-only experiment. Doug has secured patents in the U.S. and Europe, has years of prototypes behind him, and some very real test data pointing to a new way of turning watts into speed. We tested some of his earlier work, and now that he’s refining his design, we thought it would be the perfect time for an interview. I connected with Doug to discuss his invention, its origins, and why he believes the Spreng Reng might be the first chainring in 140 years to truly improve on the circle.
What is the Spreng Reng?
The Spreng Reng chainring stands out for its patented quasi-hexagonal shape, a design registered in both the U.S. and Europe. Unlike traditional oval rings that only improve efficiency through the dead spots of the pedal stroke, the Spreng Reng claims to enhance performance within the power stroke itself. This unique geometry reportedly achieves a 50% reduction in friction from chain-link stiction, a 50% intermittent reduction in articulation friction, and a net torque increase without compromising gear speed. On the bike, that translates into a smoother, more fluid pedal stroke and an easier cadence on climbs, all with no adaptation period required.
Real-world testing backs up those claims: Hunter Allen of Peaks Coaching Group recorded a 26-watt gain and a 5% faster climb using a 36T Spreng Reng compared to a 34T round ring. Developed since 2016 through multiple prototypes, the current version represents what creator Doug Brown Jr. calls the “final” iteration. While it’s optimized for climbing, the design’s potential spans road, gravel, and MTB applications, and even Hour Record pursuits.
Brown’s ultimate goal? To license the technology to a major groupset manufacturer, bringing this performance-focused innovation to a broader market. It’s a very interesting idea, and having tried the newest Spreng Reng, we can safely say the ring has a unique feel; if it were available to the masses, it could be an option for those who struggle with climbing or are looking to optimize their form.
We decided to sit down with Doug Brown Jr. and discuss what could be the next big thing for going uphill – enjoy!
Speng Reng | BikeRumor
BikeRumor (BR): Who are you and what is the Spreng Reng?
Doug Brown Jr. (DBJr): I’m just an avid cyclist, beginning in 2008. The current Spreng Reng is the second iteration of a unique, patented chainring design that originated from an earlier asymmetric version featured by you at BikeRumor years ago. That first version helped me climb with a smoother cadence, but this new one is on another level—it’s quasi-hexagonal in shape, so unique that there isn’t even a proper geometric name for it. Our first true hexagon prototype rode horribly, but rounding the vertices made it smooth and powerful.
BR: What’s your background—engineering, design?
DBJr: None of that. My past life was circulation director and marketing for a national TV program guide. No mechanical engineering background, just what I’d call a real-world education in chainring design. The project began in 2016 after I read a short VeloNews article by Coach Trevor Connor about climbing cadence. That one-pager set me off chasing the idea that increasing cadence could unlock climbing performance. Spin to win.
BR: So what problem were you trying to solve?
DBJr: Honestly? I wanted to climb better. I had this strange desire to make climbing easier by enhancing cadence, and that’s where Spreng Reng started.
BR: How does it actually work compared to other non-round chainrings?
DBJr: The biggest thing—and I can’t stress this enough—is that Spreng Reng improves the power stroke, not just the dead spots. It cuts chain link stiction and articulation friction by 50% inside the stroke, and it adds net torque without sacrificing gear speed. Other non-round rings only help in the dead zone, and they often make the power stroke harder. The Spreng Reng flips that logic.
BR: Does it still use your old asymmetric idea?
DBJr: No, the current version is a complete redesign. Totally different shape and totally different performance benefits.
BR: Can riders use it every day? Or just for special events?
DBJr: It’s daily-ride ready. Like the first version, there’s no adaptation period. You just bolt it on and climb faster.
BR: Do you have power data to back this up?
DBJr: Yes. Hunter Allen from Peaks Coaching Group and Wayne Stetina have thoroughly tested it. Hunter saw a 26-watt increase, higher cadence, and cut 1:21 off a 28:15 climb using a 36-tooth Spreng Reng versus a 34-tooth circular ring. Wayne found similar benefits and helped refine mounting orientation. The Silverstone Sports Engineering Hub is also conducting lab tests using its unique efficiency rig.
BR: How many prototypes are we talking here?
DBJr: A lot. We’ve gone through multiple shapes, profiles, and orientations to get the smoothest pedal stroke. The current one we’re testing now is as good as it gets—I don’t think there’s much wiggle room left in chainring design.
Are Spreng Rengs Already in the Pro Peloton?
BR: Are professional riders using these?
DBJr: Yes, but I can’t disclose names. It’s tough to get a WorldTour team to test anything not handed to them by a major drivetrain brand. But persistence has gotten me in some doors.
BR: Could the UCI step in if it proves too advantageous?
DBJr: Unlikely, as long as the rings are commercially available within a set period. That rule exists to keep tech open and prevent one team from hoarding an advantage.
BR: How is Spreng Reng different from other non-round rings that failed in the past?
DBJr: The difference is simple: this one actually improves performance in the power stroke. I’ve ridden all the others. They never felt faster—just weird. Spreng Reng feels smoother, easier, and genuinely faster uphill.
BR: Why only an inner ring?
DBJr: We did prototype a 50-tooth quasi-octagonal version, and it worked fine. In fact, I think it could help with records like the Hour Record because of the efficiency gains. But climbing is where this design shines the most. And yes, it could easily slot into 1x setups where mechanical advantage is lost compared to a 2x setup.
BR: Manufacturing—how are you making these?
DB Jr: Initial steel prototypes were sourced from Tri-City Laser, and the 7075 aluminum finals were produced by ProtoLabs. We’ve done 34, 35, 36, 38, and 40-tooth versions so far, plus the 50T. The patent covers a wide range of polygonal designs, starting at six sides, providing flexibility.
BR: Any warranty or crank compatibility issues?
DBJr: Not that we’ve seen. Shifting has been fine, no biomechanical issues either. Just bolt it on and ride.
BR: Is there Gravel and MTB potential?
DBJr: Definitely. No reason it wouldn’t work in those disciplines. The efficiency gains are applicable across various terrains, but climbing is where they truly shine.
BR: What’s the end game here?
DBJr: Ideally, license the patent to a groupset manufacturer. It’s most valuable when coupled with an entire drivetrain. But if that doesn’t happen, I’ll go direct-to-market with a website.
BR: Final word?
DBJr: After years of prototypes, testing, and study, I believe it’s impossible for this design not to provide a climbing benefit. The question isn’t if it works, but how much. The Silverstone testing should provide an answer soon.
Will we see the Spreg Reng at any events soon? After only one day of testing with a 36-tooth Spreng Reng, British Hill Climb National Champion Harry MacFarlane has decided to use a 38-tooth Spreng Reng during his hill climb title defense on Sunday, October 26.
What Next For Spreng?
The Spreng Reng isn’t a marketing gimmick or a tweak on oval rings. It’s an entirely new approach, one born from curiosity and stubborn persistence. Doug Brown Jr. might not have the weight of a drivetrain giant behind him, but his chainring is doing something the industry hasn’t managed in more than a century: making the circle obsolete, at least when the road points uphill.
Whether the Spreng Reng becomes the next big performance upgrade or remains an underground curiosity, it’s a reminder of where innovation often comes from: one rider, one idea, and an obsession with making bikes faster.
