First Impressions: absoluteBLACK Oval Chainring (Part-I)

Despite a recent resurgence in popularity, oval chainrings are not new technology. Dating as far back as 1890, non-round chainrings have made numerous appearances in the marketplace, with the most in/famous being Shimano’s Biopace. More recently, oval rings enjoyed a boost in popularity when professional road racers Chris Froome and Sir Bradley Wiggins used non-round rings in their quests for Tour de France victories. And now, oval chainrings such as those offered by absoluteBLACK are seeing more use among off-road riders.

Why would someone choose an oval chainring instead of a round chainring. According to absoluteBLACK’s founder Marcin Golec, cyclists don’t produce even power throughout their pedal stroke. His company’s oval chainrings maximize the portion of the stroke where power is produced, and minimize resistance where there is less power. In layman’s terms, the ring is effectively larger where the rider has the most leverage (or power), and smaller where the rider has the least leverage/power. Unlike some competitors’ oval rings, absoluteBLACK does not rely on a single timing and ovality setting for all chainring sizes. Each chainring size has a slightly different setting, which is optimized for the intended usage.

absoluteBLACK manufactures oval chainrings for road, mountain, cyclo-cross, and gravel applications. The company’s chainrings are CNC-machined in Poland (from German materials), and then anodized in the UK. In addition to their extensive line of chainrings, absoluteBLACK also manufactures single speed and extended-range cogs, as well as derailleur pulleys, disc brake rotors, and bashguards. For Part-I of my testing, I chose the company’s direct-mount RaceFace Cinch model, which I paired with RaceFace Aeffect cranks. Like nearly every other 1x MTB chainring, the absoluteBLACK ring features a narrow-wide tooth profile, and is available in 26, 28, 30, and 32T sizes.

Riding the absoluteBLACK-equipped bike for the first time certainly felt unusual. Using my normal range of gears, I experienced a pedal stroke that was choppy and uneven. Shifting to a bigger gear smoothed things out, but at the same time, I didn’t feel over-geared. With my mountainbike’s 11-42T cassette, I found myself using cogs 2-3 teeth smaller on flat or rolling terrain. By the second or third ride, I no longer noticed the absoluteBLACK chainring’s ovality, and was able to produce a smoother–albeit, slightly lower cadence–pedal stroke. Where the oval ring really shined was in situations where both traction and momentum were important, such as riding on snow and ice, or through rock gardens.

aB montage

For its intended off-road use, I’m sold on the absoluteBLACK oval chainring. Whether cruising fire roads or climbing steep, technical singletrack, my pedal stroke feels smoother and the bike’s velocity seems more consistent. While my Strava times don’t reveal any major improvements in speed, my seat-of-the-pants testing tells me that I finish rides feeling more refreshed when using the absoluteBLACK oval chainring. Time will tell if the oval design is more prone to chain drop, but thus far the only derailment occurred when the drivetrain was completely covered in thick, sticky mud (which was mixed with dead grass).

In Part-II, I’ll report on how absoluteBLACK’s larger oval chainrings (40-42T) perform for paved and gravel road riding. It will be interesting to see if the oval ring offers similar results in terrain where efforts tend to be more sustained, and traction is less of a concern. Also look for an update on how the 28t MTB chainring survived a typical Colorado winter.

Disclosure: absoluteBLACK provided review samples for this article, but offered no other form of compensation in exchange for editorial coverage.

6 thoughts on “First Impressions: absoluteBLACK Oval Chainring (Part-I)

  1. I am deciding on the 30T or 38T to replace the 32T on my new Kona Process 111. It is equipped with a SRAM 10-42 11 speed. I have always had multiple chainrings before, and when testing the 111, felt like I wanted one more gear. I understand the 30T oval may feel like a 28T. Did you feel that way? Any impressions or thoughts for me?

    1. The aB website has some really good info on how to select the right gear (scroll down to “What size should I choose?”).

      I, personally, don’t take into account whether a ring is round or oval when choosing size. Instead, I calculate the lowest gear ratio that I’ll need, and then find combination needed to produce that ratio. I’ve found that oval rings don’t feel like they have quite the +/- range that manufacturers claim, so I err on the side of caution to avoid spending all my time in the biggest cog.

      My advice? Go with the smaller chainring and shift to a slightly bigger gear if it’s too easy.

      1. Thanks. Having looked at that vid, and done some calculations on Sheldon Brown’s calculator, and heard from you, I am going to go 28t. Thanks again for your blog and your input. I am still loving my Clement USH tires we talked about before.

        1. I think you’ll be very happy with the 28T ring. I find that I rarely use the 28/42 combo, but when I do, I’m glad I have it.

Comments are closed.