Want to climb better? Interested in oval rings? Maybe there’s another option. Inventor Doug Brown has spent two-plus years examining drivetrains and pedaling efficiency, and he’s come up with a very different way of improving climbing efficiency. His unique chainring enhances the efforts of your dominant leg to improve your overall efficiency going up the hill. It’s not oval, and it’s only sort of “not round”. But it’s definitely different.

Douglas Brown invents oblong off-center chainring to make climbing easier by improving your spin

There’s no name for the design yet, but it changes the way your efforts are applied to forward momentum. The concept is simple: Offset the chainring’s center from the crankset’s center so that your dominant leg overcomes any deficiencies on your weak side. Where an oval chainring provides more leverage in the power zone for both sides, this one simply maximizes the input on your dominant side. Beyond that, one of the biggest differences between an oval or otherwise non-round chainring is that it’s smooth. Doug says there’s none of the pulsing that can be felt with some other non-round designs, as long as it’s clocked correctly.

The chainring is completely circular in the power zones, as shown by the perfect red circle we laid over their drawing, but it does flatten out slightly in the dead zones.

With their design, a 39-tooth chainring has a 39/36-equivalent, and is designed for someone who normally rides a 39, but feels like a 36 in the power zone of the non-dominant leg. “They way I envision this being used is on something like the Easton EC90 cranks, where the rings are easily interchanged,” says Doug. “A rider could switch it to this ring on days when they know they’ve got a big climbing day. But also could work for power-heavy events like cyclocross and gravel races. But mostly climbing.”

“Essentially, you’re using one leg to help the other leg. It keeps you from getting bogged down on the climb by keeping your cadence higher. Or, it keeps you spinning, so your legs are fresher when you’re not on the climbs.”

He says, with normal oval rings, you’re only getting a radius reduction in about 25% of the pedal stroke. With his, the dead spot reduction is much broader, providing a larger benefit to the non-dominant leg. But since you’re not making as much power in the dead spot, the full radius is maintained for your dominant leg. And if you’re doing a multi-day event? Just rotate it so you give the other leg a “day off” on the second day.

Douglas Brown invents oblong off-center chainring to make climbing easier by improving your spin

The idea is to use this as the small chainring, leaving your outer chainring the same. Because there are no dramatic dead spots or weird shaping, there should be no problems with shifting. While it seems odd, they’ve done a lot of testing to prove the concept. The product is in development, and Doug’s hoping to license the design rather than become a manufacturer. So, there’s no official product name yet, but he’s working on it. We’ll keep you posted on its progress.



  1. nowadays the “engineers” become and behave more like “artists”…
    OMG, to accept that it’s normal to have one dominant side (and one weak side) and to emphasize that is plain crazy… to encourage off-balance is plain crazy.
    i am sick of these “engineers”!
    and, the question is, why do you publish this non-sense? well, maybe to create confusion… confusion is part of the marketing success… confuse people then it’s easier to sell crap…
    i am sad seeing these non-sense articles.

  2. Just like oval rings, probably more to do with adaptation than any real efficiency improvement. If you have a left-right leg pedaling imbalance then focus on the root cause, don’t mask it with component choice and let it fester.

  3. Looking at all these improvements that are supposed to make you faster: aero, nano tyre compounds, ultralight carbon, deep wheels, intelligent suspension, low friction pulleys, grease etc only give you very marginal benefits while the cost is high.

    No one talks about training, technique, nutrition and even psychological exercises which provide far greater benefits than a shiny new part.

    On the other hand people shun ebikes and EPO like some plague but they give far better performance per dollar than any of these new components 😀

    • Marin – to be fair, this is bikerumor. If you type “coaching, cyling” you’ll come out with literally hundreds of thousands of entries regarding training, technique, nutrition and mental training. Heck, some of them even might work.

  4. As someone who’s struggling to ride at all following back surgery, I find this intriguing for recovery (hopefully not permanent). My left leg was essentially paralyzed before surgery, and even 6 months on, my L/R balance has only improved to 40/60. I’m told it’s unlikely I’ll ever recover fully. Maybe not a product for healthy youngsters, but for injured boomers it might work.

  5. OK, first of all I’m always simply amazed at how quickly anyone can be so critical of an invention they have never even experienced. Simply amazing! As the inventor of this design, and an avid cyclist, I along with two very talented mechanical engineers at Paul Hammerstrom Design (i.e. Paul Hammerstrom & Josh Yablon), either of whom can run circles around me with respect to engineering something of this nature, have worked diligently on this project since October of last year and let me assure you all it has been and continues to be a developmental journey. One which I truly desire sincere input, suggestions, and criticism from anybody since I’m a self-professed “Great Listener”. With respect to it’s intended benefit, that is improving/maintaining your cadence on a climb, the design simply works, the steeper and longer the climb the better. We would not have gotten this far without first proving it works and works well. For all of the critics of the design, first of all perhaps it was not explained in the most easy to understand manner but physics is never that simple, even for a simple machine like a bikes drive train. So, for all you armchair critics out there who want merely to be critical, I challenge you to try and create any real, meaningful improvement in either the mechanical or bio-mechanical advantage of a bike’s drive train. After over two years of trying, with one complete failure on a prior crankset design, I can assure you there is not much, if anything, left to improve upon unless you can find a way to break the laws of physics! And good luck with that.

    Doug Brown Jr.

  6. This is a cycling news web site so they can show us what’s out there and it is up to us like it or dislike it. They are not saying that we need to buy it or like it.

    I don’t particularly like the idea but people will always thinker with new ideas and that’s just fine.

  7. Only in today’s world do we need to create chainrings to cater to our non-dominant leg so that it doesn’t have to work harder and feel oppressed.

  8. Interesting idea, but isn’t it much more preferred to work on evening out your pedal stroke? When I realized one leg was much stronger than the other (one leg was always achy, and I’d feel a lot of pressure on one side of my saddle), I physically started pedaling harder one the non-dominant leg. After a few months of this, I feel much better overall. I think it’s much more important and helpful to even out your pedal stroke than cater to and emphasize the dominant leg…

  9. I think this a brilliant invention, especially in its simplicity.
    Yes – it will pose a real benefit for those with long-term injury or disability.
    Yes – it will increase the pedaling efficiency and so power and speed of those with natural imbalance – slight or otherwise.
    And yes – it will also be of real benefit for those who wish to beast their weak leg into getting stronger by using it in the reverse of its original design intent by using a chainring profile that increases the lever and required power of the weaker leg. Imagine a winter training of self-beasting and coming into next season with both legs of equal power output.!

  10. Steve, thanks for your comments. To be brief, the real, intended benefit for this design is for example to train on a 39 tooth round ring and then switch to this ring for a hilly gran fondo, century, or road race. Obviously there are other ratios possible. The bio-mechanical advantage you receive (i.e. improved cadence ability) by having an additional mechanical advantage for one leg doesn’t let you get bogged down on a climb. Think about that, instead of a mechanical advantage in the dead spot where you produce no power, you’ll now have a beneficial mechanical advantage within the complete power phase portion of the pedal stroke to increase or maintain your cadence. It’s like having two chain rings in one. With the original 39t/36t version of this ring, providing 37 total teeth, I can go up a 10% grade in a 25 tooth cassette cog and never have the need to stand because my cadence does not substantially drop. Climbing is all about cadence! If you have any doubt look for Trevor Connors article titled, “The Spin On Climbing” which was published in Velo News in May of 2014.

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