It makes sence, I never have understood how the rig shape made a diferance, I just have that one experience that has made me feel that oval chainrings are better, but I have experiences that also point that round rings are better, I just had to look back at old rides and look at the starva segments .
1 Like
The research is inconclusive. Interestingly one of the more consistent benefits that studies “found” is that short intense efforts see better power with non-round rings. It gets dirty when you take into consideration crank based PM’s and the way that non-round rings inflate power by something like 2-4%. For me that would be 25-50W. It’s crazy that I use a crank based PM and have seen no change suggesting round rings may be better (for me). Others say the same. I just have not come across anyone who says the opposite. That’s means nothing as my sample size is small but, just more things that make me wonder.
To anyone thinking of buying I’d research:
- Do non-round rings inflate power with crank PM’s.
- How the hip, knee and ankle joints change while pedaling with non vs round rings.
- HR and lactate production/clearing with non vs round rings.
1 Like
chris froome used them, that means there must be some kind of marginal gain, maybe the gain just comes if you spend to much time looking at your stem while racing or ride at a high cadence up climbs.
1 Like
I’ve absolutely no idea if I get more power when using oval rings as I’ve no power meters on any of my mountain bikes. However if I get better traction (as in less spin-outs) then I’m assuming that I’m wasting less power than with a round chainring.
Taking times off Strava is fraught with difficulties especially off-road as there’s so many other variables that unless one time is significantly faster, say 10% quicker, then as far as I’m concerned, it’s just a time that might be quicker but it might be slower.
I just wanted to add my recent experiences.
I switched both bikes (TT and road) to Absolute Black oval inner rings about 6 months ago. I really liked the feel; pedalling on an oval ring “made sense” to my legs.
As the big ring on my road bike had worn out, I went with a Q-Ring big ring (and Q-ring inner, went from 50-34 to 52-36). My road bike runs Sram Red Etap 11 speed. So I was worried the shifting would be poor. I had 30 days to return the big ring for a No-Q big ring under the Try-Q deal.
Well, the shifting is better than on my previous round big ring. I guess I hadn’t realised how worn my previous (round) ring had become (18,000+ km). So there was a very noticeable improvement in front shifting. As for use…my right patella tendon issue that was coming and going every month since I started Trainer Road about 18 months ago, has gone. I had forgotten about it until I hopped on my TT bike for TR session and then got a slight pain after. That reminded me. I wasn’t expecting oval rings to resolve my tendinitis. So I need to purchase an oval big ring for my TT bike now.
Note about my right knee
Before people say I may have a bike fit issue to be getting this injury. My right knee has had 6 surgeries, no meniscus left, hardly any bone cartilage left etc. So any symptoms with that knee is a “special case”.
1 Like
Ok so I just decided to do a 20 minute power test with an Osymetric vs Round Chainring and see what the results were. Here is my video of it. I cover some installation stuff at the start.
I used Absolute Black chainrings on my road bike for about 3 months. I liked the feel of it but shifting was terrible (multiple chain drops). There is no difference in power generated compared to round chainrings (measured with Favero assioma duo). There is however difference in muscle recruitment, which feels better for some people.
Effects of a Non-Circular Chainring on Sprint Performance During a Cycle Ergometer Test
The Osymetric non-circular chainring significantly maximized crank power by 4.3% during sprint cycling, in comparison with a circular chainring
So, I’m going to try Oval this winter, however a quick question.
Wil using an Oval on a trainer have any negative impact (due to the slight speed / power fluctuation)
Negative impact on what?
errr, anything 
Actualy I was maybe overthinking: the oval rings slightly fluctuate the force needed during rotation, would this impact (overwork) in erg mode as the trainer tries to control it… 
That will depend on the specific trainer gearing you use. High gear with flywheel speed and/or slow reaction trainer will likely be a non-issue. Not sure if low speed and fast trainer will lead to a problem, but I think it’s possible.
I know one rider who has oval rings on one bike and he’s used all my trainers with no apparent issues. But he’s a big guy who likes high flywheel speed and picks big gears to get it.
Posting here instead of just adding another similar topic.
Have 5800 105 and need new rings and trying to decide between 6800 and absolute black ovals. I keep reading how they over estimate ftp and have poorer shifting. My thinking for inflated ftp is that I only have one bike with a powermeter (stages gen 3 lh) and that’s the one on the turbo (power match) too so it doesn’t matter if the ftp is up 5% since it’s one bike so it’s not like I’m comparing anything?
Am I correct in my thinking or does the oval-ness mess up training? I can’t see how this would mind you.
Your thinking is right. Although, if the new rings do inflate your power, you’re best to do an FTP test to reset your training. But to be honest, I didn’t bother when I switched my road bike. I had ideas of doing some speed-at-given-power testing between the rings but never got around to it. If it has inflated my power, it has been unnoticeable to me.
At my low FTP 2 to 5 percent is minimal anyhow!
I’m not an engineer…It’s the type of PM and how it “records” angular velocity which determines whether power is inflated or not.
Stages is subject to inflated values because it records one revolution as one event. The increase in angular velocity therefore skews high. Other PMs measure many many more times per stroke nullifying the constant velocity argument. SRM calibrates with round rings to get slope which they say is exclusive to that PM=doesn’t matter what type of ring you use.
“Torque is torque”. Other PM’s such as Powertap measure at the hub so no inflation. And on and on and on…
Very true Landis.
I put ovals on all 3 bikes. Gravel (4iiii) and road (Power2Max) should inflate. TT (Pioneer) shouldn’t. I couldn’t notice any inflation in my training* once I switched. So must be on the very small inflation side of things for me.
*I do most of my training on my TT bike though.