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Oval Chainrings vs. Round Chainrings featuring Absolute Black [Video]

Words by: Liam Woods

About Oval Chainrings ft. Absolute Black:

It is no secret that oval chainrings have been a controversial topic ever since they came out. From the old school, bio-pace rings to the new and highly advanced oval chainrings from brands such as Absolute Black. The amount of testing and development the team at Absolute Black put into their products is simply mind-blowing and it can be seen in the quality of their products. You might be saying to yourself, well that’s great and all but I can’t run any tests, I don’t have an oxygen monitor, power meter, and near perfect trail conditions to get accurate results, how do I know if an oval chainring would benefit me or my bike? Well, because we can’t really replicate chainring testing as Absolute Black can, we decided to do some real-life back to back testing with a few of the guys at the shop.

We had a few riders at the shop, including myself on both my cross country bike and my gravel bike, perform a back to back test between oval and traditional chainrings to see if they could notice a difference and see if one feels better than the other. Adam and Chance went through the adaptive period that Absolute Black recommends, with about 10-15 rides over about 2-3 weeks to get used to the differences. Michael had never ridden the oval chainring until the day of the test, so he was fresh to the feel. We then put each rider back on to the round chainring after a test run to see if they could in fact, notice a difference on the same section of trail back to back.

Theory:

Because bicycles are powered by humans, the way we input power to the bike is not perfect...well not even close. Since power isn’t distributed evenly in a pedal stroke, there are areas that more power is put into the cranks and other spots where less power can be physically put into the cranks. Turns out that this power pattern looks like an oval, who would have thought? Absolute Black’s goal was to maximize that power input when putting the most power out and minimize when the cranks are at the spot with the least amount of power. Each style of chainring has been optimized for the intended use, so mountain bike, road and gravel, and time trial bikes all have different amounts of ovality and are also timed differently to help match the position of the rider on those specific bikes. By making the chainrings oval, you as the rider should be able to put down power more evenly. Now combine this with technical climbing and you can actually be more effective with your pedal strokes making climbing a bit easier. Same with riding on flat ground, having a smooth pedal stroke and power output to the back wheel will make things feel a bit easier. I think this is especially noticeable when riding with flat pedals on a mountain bike, you now can only put down power from about the 2 o’clock position down to the 5-6 o’clock position without being able to pull up. Because of the oval timing, that helps get a smoother, more effective pedal stroke.

Absolute Black Tech:

Since Absolute Black did all the tests over many months with hundreds of riders, below is some of their comparison between oval and round chainrings direct from Absolute Black themselves:

“It is well known in practice that various adaptation phase is required to get fully adapted to a new pedalling technique. That is why researchers at University of Primorska aimed to explore the effects of long-term adaptation using absoluteBLACK oval chainrings on mechanical and metabolic functions during cycling at submaximal intensity. Seven cyclists who used non-circular chainrings (52/36 or 50/34) for at least one year were recruited. Participants were recreational road riders with no history of muscular-skeletal injuries in the past 5 years and were riding between 3000 and 10000 km a year. Participants used their own bicycles mounted on a direct-drive ergo-trainer and then completed two 5-minute tests at 75 % of their maximal power. In one of the trials, they used round chainrings, whereas in the other, they used absoluteBLACK oval chainrings in the same size. Trials were completed in a random order and with enough recovery between the trials to avoid fatigue effects.

Researchers used special force pedals mounted on the participant’s bicycle and recorded forces at a sampling rate of 1000 Hz. At the same time measuring continuously oxygen consumption (VO2) and carbon dioxide output (CO2) using a metabolic chart. This setup allowed researchers to assess pedalling effectiveness using the index of effectiveness (IE) for the entire pedal cycle and additionally for the downstroke. Average gross efficiency (GE) was calculated as the ratio of work rate (power output) over metabolic cost rate calculated from VO2 and respiratory exchange ratio. Results were statistically compared using a paired t-test with the level of significance set to p < 0.05.” - Absolute Black Science Lab

Summary of the results when using absoluteBLACK oval chainrings tested by Absolute Black:

Up to 9% increase in Force effectiveness,
up to 7% less oxygen consumption,
up to 15% less ventilation and
up to 10% heart rate decrease when using oval chainrings versus round.

So as you can see from the tests that Absolute Black has run, there are some very serious improvements that can be made for most riders by using an oval, how those translate into the real world is hard to prove. We have done our testing and formulated our own opinions about oval vs round chainrings, while not a scientific test, we feel that this test is the most realistic for the average rider.

Worldwide Cyclery’s Opinion:

Thus far, I have had the most amount of time on oval chainrings, specifically the Absolute Black chainrings. The two bikes that I put in the most hours on are my Mondraker XC bike with an Absolute Black 32t chainring mounted to my Raceface Next SL crankset, along with an Absolute Black 42t chainring mounted on my gravel bike with Easton EC90sl cranks. At first, I tried it on the gravel bike and immediately loved how it felt, even before the adaptive period. I found that on flat roads I could consistently stay on top of my cadence and the gear which allowed my pedal strokes to feel very smooth and consistent. On climbs with a steady gradient, I found I could ride a gear higher while maintaining the same cadence allowing myself to go faster and have more effective pedal strokes. All of these translate to having a faster average speed and less fatigue over a 2-4 hour ride.

Next, I put it on my xc bike and I won’t lie, I was a bit skeptical to use an oval chainring on a full-suspension bike. For some reason, I had in my head that it might not work as well and cause some “bobbing” or unwanted suspension movement. Well, that also was quickly proven wrong within the first ride or two on the xc bike. There was a bit more of an adaptive period on the xc bike, but once used to it, I found that the same benefits I felt from the gravel bike were also apparent on the xc bike. I was able to stay on top of my gear while climbing and also felt a huge improvement while climbing technical sections. I felt that I had less of a dead zone during slow tech climbing and that I could turn the cranks over more smoothly as well as keep rear-wheel traction better in these situations. The only not so great feeling I noticed on both bikes was when I was tired and fell behind the ideal cadence for the gear I was in. It actually felt harder than compared to a round chainring at that point. I was 3 hours into a pretty big xc ride and came into a double-digit % 1 mile long climb so that might have had something to do with it as well. Turning over the pedals felt just a bit harder than normal in this situation, just something to keep in mind. For myself that is more of a rare occasion as I can typically stay on top of my cadence even into 3-4 hour rides but there are times I realize I am not a pro rider as well.

Overall, my opinion has completely changed after spending 3 or so months on the Absolute Black Oval Chainrings, from being skeptical to really liking how they feel on multiple bikes. The perceived benefits from the oval chainrings are mostly all positive and I feel that I can have a more effective pedal stroke riding on flat ground, steady climbs or maintain traction on steep tech climbs.

Adam’s Opinion:

“Seeing as this was going to be my first time riding an oval chainring, I went into the test with an open mind and zero preconceived notions. I had heard people claim that switching to an oval chainring drastically improved their pedal stroke and that it was especially useful for flat pedal riders such as myself. I mounted the ring to my Yeti SB150 and immediately went for a ride. At first, it felt a bit weird and I could definitely notice that I was pedaling an oval ring. After about 30 minutes of riding, I completely forgot about it and really started to notice how smooth and planted the bike felt. Obviously I couldn't run any scientific tests, but to me, it just felt like I was getting more of the power down and none of my power was going to waste. When I compared it to the round ring on the same section of trail, the difference was obvious. I noticed that with the round ring I would get hung up on technical climbs and sharp rocks whereas the oval, I could just power right through those sections. With about a month of riding on the Absolute Black ring, I have really grown to love it and plan to keep using it for the foreseeable future.”

Chance’s Opinion:

"At first, I was unsure if the oval ring even did anything, but after going back to a standard round ring I noticed in very technical climbs that needed some extra power it felt that the pedaling response was increased majorly! In situations where I needed to put down power to get over techy rocks, it excelled incredibly. I was eager to get back on the Absolute Black Oval chainring after comparing the two on the same ride! "

Michael’s Opinion:

“This was my first time riding on an oval chainring and to be honest, I don't have enough saddle time yet to really tell a difference between the oval and round chainring. My test of the Absolute Black oval chainring involved climbing a rocky portion of the trail which I have never climbed before. There were some sections on the trail where I felt like the oval chainring helped me power over some sections where the round chainring felt dead. I don't know if that's because I got more comfortable on the bike climbing this section or if the chainring really was making a difference. I think with a little more saddle time and climbing some sections that I am really familiar with, I can give a definitive answer on whether I can tell if an oval chainring is really helping.”

Final Thoughts:

After digging into the science and tests that Absolute Black provides along with doing our own testing here with Worldwide Cyclery employees, there are no doubt some real and noticeable advantages to running oval chainrings. From having a more effective pedal stroke, to maintaining traction more on steep and tech climbs. Myself and all of our shop riders who did the test could feel the improvements from the Oval and while Michael isn’t a full believer, he still did notice some improvements while climbing. The Oval chainrings help improve the imperfect human pedal stroke, not only making your pedaling and power more effective, but also make your entire riding more effective. It’s an easy part to change on your bike that can have some significant upgrades to your riding, compatible with tons of cranks, what do you have to lose by trying out an Absolute Black oval chainring?

This article was written / authored by Liam Woods. Liam has been in the bicycle industry for over 10 years as a racer, professional mechanic, service manager and as of late, media and content creator. Liam has ridden thousands of different bikes, ridden countless components, tested endless MTB apparel of all kinds and written reviews on it all. He's a key piece to the Worldwide Cyclery "All Things MTB" content creation puzzle. He also makes consistent appearances on the Worldwide Cyclery YouTube channel and Instagram.

If you're one strange human and would like to read the transcript of the video above, continue reading below!

Oval chainrings. What the heck are they, are they worth the upgrade, why did one of your buddies tell you that they're really good and another buddy tell you that they suck? Well we talked about this a lot and we get this question all the time. We also wrote an article on it a long time ago and today in this video we're gonna dive into everything about oval chain rings on mountain bikes especially with a focus on how they actually work for the average mountain biker.

Well when we decided to make this video we got in touch with who we feel is the absolute leader in the oval chainring world and that is absolute black: a German company that manufactures beautiful aluminum cnc chainrings right in europe and these guys have done extensive testing on oval chainrings - like ridiculous testing. Go to their website, watch their videos, read their whole thing on why oval. It's all really interesting stuff to me. When I digest all of that I feel like it's very focused on effectiveness on the road in particular and I don't care too much about that as a mountain biker. When oval chainrings were introduced, in in my experience, I looked at them, I saw them, I heard about them and I thought it was kind of more of like a cross-country rider roadie thing and wasn't really all that interested. Then I happened to read some quotes in an article from Cedric Gracia years ago on oval chain rings and when I saw that I was like oh I should actually give these things a try, and it's a pretty cheap upgrade. You know oval chainrings can be had for around 70 bucks or so and it's an easy thing to test and then swap on and off your bike if you don't end up liking the thing. Once I tried them I pretty much never went back. I really enjoyed them as a mountain biker because I like technical climbing - rocky, rooty stuff. I like to just try and motor my bike up that stuff, I think it's entertaining to do and fun to do and it's a challenge. Oval chainrings for me on a full suspension mountain bike felt like I had more traction, better power delivery to the rear wheel, and just could climb stuff better and it felt like an advantage in technical climbing which I really enjoyed. So that was my experience with them, everyone's got a little bit different take on it. The super nerdy efficiency effectiveness roadie gains on the whole thing, we're not really gonna get into because this is a mountain bike channel so we're gonna talk about how mountain bikers feel about these things. So two people's opinion that I really respect: Liam Woods, our head mechanic here, former roadie and a mountain biker, and Jonathan Lee who's a nationally ranked road cyclist and mountain biker who works at Trainer Road. That guy's brilliant, so i'm gonna get both of their opinions on this thing then we're gonna go out onto the trail and get some average mountain bikers’ opinions on these things and have them ride a regular chain ring and an oval chainring back to back on the same bike in the same portion of the trail so let me go get Liam.

Willie, tell my mountain bike friends your experience with oval chain rings in less than a minute. Go ahead. Alright so I have them on both the cross country bike and my gravel bike. First, on the cross country bike, I really noticed it on technical climbing. Technical climbing was pretty immediate with the pedal stroke and the way the oval chainring kind of reacts other than that you know I don't think it's all that noticeable but definitely on the climbs. Gravel bike, I think it's awesome. It's not a gravel channel but it really, on the rigid, could react to the same on a hardtail too. It really reacts well. You can get on that efficiency or effectiveness you can stay on top of your cadence better and that's really what I thought. I felt like I could stay on top of my cadence better and I could get a smoother pedal stroke on both bikes. So yeah. A fun experience. Well I definitely want to try one on my gravel bike which I have been riding a bit lately and I pretty much just ride it on mountain bike trails and it really has no traction compared to my mountain bike climbing, so any traction gains I could get there I'm excited to test that out at some point. Alright cool well now let's hear Jonathan's opinion.

Yeah I think people should try it. They're awesome for the right bike and the right rider. For my Yeti ASR that I had, they had a tendency to bog and it relied a lot on chain tension to be able to stay in the right spot in that pedal stroke kind of give you that anti squat in that nice solid pedaling platform and with oval chain rings it improved dramatically. With my new bike the SB100 it doesn't have as much of that effect because it doesn't seem as reliant upon chain tension perhaps. I'm not sure. I've used them on the road, use them on mountain, and what I find is that usually I have this initial kind of like adjustment curve or like whoa it feels different. For me personally, I've never been able to measure any difference in heart rate or anything else like that but I have certainly noticed that there are some benefits like if you can stay on top of the gear or kind of spin a quick cadence it really works like I feel like it's easier to stay up there the wall. On the downside of that if you really get drugged out and it's really steep I find that it's pretty tough to kind of get back on top of your pants if you get drugged down but depending on the bike depending on the rider and the terrain it could be something that would really improve the ride for a lot of people and I think they should try it.

Well there you have a few opinions, now let's go out on the trail and see some more - I would call them “average, novice mountain bikers” opinions. So a few of our staff, a couple of these guys have been riding these oval chainrings for a couple weeks. So absolute black recommends you go through sort of a I don't know a getting used to it period where you kind of learn and understand how the sort of thing feels and we're gonna put them on the same section of trail same bike swap them back-to-back with a round ring and oval ring and hear their thoughts. You're also gonna see Michael. Michael's been riding mountain bikes a super long time and he has never ridden an oval ring so it'll be interesting to see his thoughts immediately on the same section of trail on his bike that he's used to with his round ring and then hit an oval ring. So let's go see what those guys think, how these things actually feel out on the trail and see if they seem like they're a worthy upgrade.

What's up guys? Today we're out here on the trail and we're testing absolute black oval chain rings against the standard round chain ring. We have three riders: Adam and Chance who have been on the chain rings for about two to three weeks getting used to how the oval chainring rides and kind of getting that adaptive period, and then we have Michael who's never been on an oval ring before and he's gonna get out here on one for the first time today to give it a shot and see if he can notice the difference on his first ride compared to the round chainring.

What's up guys I'm Adam I've been riding the absolute black oval chain ring for a couple weeks now riding it on my SB150, I ride flats and I've definitely noticed a big difference between the round and the oval. I noticed right away that it felt a little more efficient I was able to kind of put the power down. I felt like I was translating more of my pedal stroke to the trail whereas on the round I kind of would get hung up in certain sections especially with the technical climb we just did. As soon as I switched back to the round I kind of felt myself getting hung up and almost having my feet fly off the pedals and with the oval that wasn't happening at all it's just a nice even stroke the whole way around, felt really smooth, really enjoyed it and I'm pretty convinced. You know I wasn't really sure if it would make a big difference, I hadn't ridden an oval chain ring in my life prior to this, but I definitely plan on using it moving forward. So yeah I'm a fan.

Hey guys, Chance here. Like I said before I've been on this chainring for about two weeks now. Immediately after hopping back onto a standard chain ring I could already tell a difference between the two in technical sections where there's kind of like immediate rocks where you kinda have to put down some power to get over them. I felt that it was very responsive compared to just a standard chainring.

What's up guys, this is Michael from Worldwide Cyclery. As you heard earlier this is my first time on an oval chainring. As far as some background, I'm your average rider, I ride maybe once a week to try and keep the dad bod in shape, doesn't always go as planned but not too picky about parts. I kind of just get on the bike and ride. So that being said, as you know, I've been on a round chain ring going up the climb, it’s a bit more technical, some rocky sections to pedal over. So on the round chainring, I felt pretty comfortable, there were some spots where it felt a little dead trying to get up some technical sections swapped into the oval to be honest i didn't tell too much of a difference on my first climb up but on the second climb there was a couple spots where I noticed on the round there was a little bit of dead zone but with that oval chainring I felt like I was able to pedal over some of those technical sections a little bit better. This was just a very simple test so I would like to ride it a bit more to get a full review on it but initial impressions are pretty good, can't tell too much. I'm sure more advanced or you know riders who are doing technical climbs a bit more could tell a big difference, but for me, an average everyday rider, not so much right now. But I think with maybe a couple rides under my belt on some trails that I'm used to I could definitely give them a more definitive answer.

Well, there you have it, opinions all over the place from all sorts of different people on oval chain rings and yeah it is one of those things that you know you can tell some bikes it'll make a bigger difference on than other bikes, some riders it'll make a bigger difference. Whether they're very sensitive to how their bike is pedaling, if they're climbing technical stuff, if they're riding on flat fire roads, everyday, a lot of different scenarios for everyone out there. Different opinions from different people from different bikes. To me personally, I think an oval chainring is an awesome upgrade cuz it's a pretty cheap one and it's also really easy to go back. You don't need to take any links out of your chain or anything, you just swap the chain ring on and off, buy the right size, test it out, see for yourself if you like the thing. It's definitely a fun thing to experiment with. I ride one now and probably will always ride one as long as there's an available size. I enjoy it because I do a lot of technical climbing. Bikes these days that I ride are really low to the ground and I feel like they get lower and lower every year and I keep hitting my pedals more and more and I think oval chainrings do help me out with that and the technical rocky stuff that I climb. So hopefully this video helps you guys out. Drop a comment below if you have an oval chain ring or if you're considering trying one, if you do check out absolute black they help us out with this video and those guys are awesome and they make the best rings in the business. Hit that subscribe button and we'll see you in the next one.