Oval vs Round Chainrings?

[oaklandhillsca]

Apologies if this has been discussed already. I probably should search, then post, but hey.

When it comes time to change my chainrings, I am considering oval. Has anyone changed from round to oval? if so, what is your experience?

My riding consists of a reasonable amount of climbing and my understanding is that is where the oval rings outperform round rings.

Thoughts?

Thanks.

[prototoast]

I use an oval inner ring with a round outer ring on the bike I ride the most, and round everything on all my other bikes. It took a while to get used to, but now I can comfortably switch between oval and round without even noticing.

No noticeable performance improvement, but I'll probably buy more oval rings in the future, as I replace worn round rings.

[Mark McM]

Oval chainrings have their adherents - som find they help with joint pain, others just like how they feel, etc. But as far as "outperforming" round chainrings, there has been no strong evidence of this. Most studies have found no significant difference in performance between round and oval chainrings. In fact one study found that when cyclists switched from round to oval chainrings, they merely changed their ankle flexion to maintain the same hip and knee joint movement as with round chainrings.

A few years ago, the Sky cycling team (now Ineos) largely switched to ovalized chainrings, after they measured higher power outputs with the ovalized rings. But then it was discovered that the SRM power meters they were using gave inaccurate results with oval chainrings. When the power meters were re-calibrated for oval chainrings, they found no difference in power from round chainrings. So the team switched back to round chainrings.

[fredd]

Good overview of the research on oval rings:
https://www.youtube.com/watch?v=jtJ7eIyqQ0E

My takeaway is that, if you want a bit more traction on steep sections, they maybe worth it. If not, probably not gonna make a difference.
If you're curious, might as well try...

[phishrabbi]

I have an absolute black 42t Oval I use on my cross/gravel/everythign bike.

I like it.

But I wasn't happy with he way that oval rings shift, so I use round for the road bike.

I can't say I really notice a difference, but the oval one looks really cool....

[TheseGoTo11]

I find oval rings seem to smooth out the pedal stroke when out of the saddle. I like it as an inner ring on the road. Where it really shines is on my single speed, though.

[SlowPokePete]

My friend swears by them.

I have them on my Lynskey...personally don't really notice any difference.

Only reason I have them is they allow a 46/30 on my crankset which otherwise I would be stuck with 50/34.

SPP

[muttley]

I ran AB oval sub compact rings (48/32) with 11-34 on my previous gravel/all purpose bike and found that for me the 32/34 oval combination really helped on those steep loose climbs. The plus with this 2x gearing is it also allowed me to keep up on road rides with my buddies (I just switched up my wheels to match the terrain).

[Krenovian]

Like SlowPokePete, I went with oval rings (Absolute Black) because I had a crankset (Ultegra FC-R8000) I wanted to run 48/32 rings on and they were the only option. I have about 130 plus miles on the oval rings so far, so my experience is limited. Here are my observations.

I didn’t have any issues adapting to the feel. On the road I don’t notice any difference between round or oval except as TheseGoTo11 has noted, riding out of the saddle the pedal stroke does feel smoother. I like that a lot. On the trainer I’m more aware of the difference (only one ride so far). The oval rings don’t seem to give me that smooth “pedaling circles” feel that round rings do. You would think it would be the other way around. This may smooth out with time.

When I ride the AB oval rings I notice that my quads get worked a lot more compared to round rings. They are definitely more sore after doing the same route at the same intensity compared to riding round rings. I’m trying to decide if this is a negative. It makes sense that this might happen knowing how oval rings work. It seems apparent that I’m using my quads more and my hamstrings less. With round rings I feel that the work is being more evenly shared between the two muscle groups.

The Absolute Black website indicates that the rings just bolt on to the Ultegra crankset and work. I and some others have found this not necessarily true. The rings are offset to the inside by about 2.5mm compared to the Ultegra chainring set. With my frame I had to place a 2.5mm shim between the drive side crank arm and the BB. Without it the inner chainring rubbed on the frame.

[Viewer]

My experience is this: when the gradient goes sufficiently 'UP', it does not matter whether you run oval or circular. What matters is whether you can keep it going at the same power. That's your legs and a change in chainrings is not going to help if you don't have power.

[Krenovian]

Forgot to say in my previous post that for me the oval ring shifting is not stellar compared to round rings. It depends where I am in the pedal stroke as to how clean a shift it is going from the inner to the outer chainring. Sometimes it’s very quick and clean other times there is some clattering before the shift is complete. This is with a DI2 setup. In synchro shift mode it is much worse. I rarely experience a clean quick shift going from the inner to outer ring.


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[fried bake]

I’ve about 2000 miles on rotor 48/32 which I like and will stick with it going forward. That being said, OCP IS a real thing and needs to be set correctly. I used the most common setting initially—which Rotor recommends checking after 500 miles or 10 hours of riding, but I did not. I waited until I had knee pain and then swapped it to the better (for me) position. Now it’s fine, but I recommend monitoring your sensations during the initial adaption phase. I am no faster or more powerful than before, the one tangible is that I feel I can get over the gear more smoothly than with round rings (have ridden road subcompact for some time now, is it’s not the change in gearing).


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[Waldo62]

I have bikes with round rings and bikes with oval rings. Round rings are good, oval rings are better. I ride both happily.

[Hilltopperny]

I use both and typically run oval rings on my 1x offroad/mtn bikes. My road bikes have round rings and are typically 2x.


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