Oval chain ring
 

Was wondering what you folks think of an oval chainring? Hype or help? I live in Florida but think that the big ring may help. Anyone have any experience? Thanks

Gimmick that comes and goes about every 20 years.

I have not ridden with oval rings since I had a bike with biopace rings many years ago. Hopefully someone with recent experience/knowledge with oval rings will chime in. I know I had no problem with them, but I had nothing to compare them to at the time. There are people that swear by them, supposedly help the pedal stroke efficiency. If I remember correctly, some riders say it eases knee pain.

I have a few bikes with Biopace, specially on one of my main road bikes, and I can't tell a difference from round. They all feel the same to me, climbing,sprinting,etc.

I have the Absolute Black 46 & 30 chainings on my Ridley Helium which is my climbing bike. Installing the chainring set gives me a deep range for 15-20% climbs that are common enough in southern Wisconsin. The oval shape may have some benefits, I do like the feel of the oval shape and I'm getting improvements on my steeper Strava segments. However, the primary benefit is the gearing. I like to keep my cadence above 65 rpms while climbing and these smaller chainrings along with an 11-32 eleven speed cassette keeps my legs fresh on longer days.

The Absolute Black chainrings install with an altered chain-line compared to the standard Ultegra 50 & 34 chainrings on the 6850 crankset. This can work on a rim brake bike, but I would not ever install these on my disc brake bike with 142mm dropouts. The chainline on the disc brake bike would be extreme while on the small chainring and several of the smaller cogs.

Even on the rim brake bike, the reduced chain-line is problematic. The front derailleur limit adjustment just barely aligned on the inner chainring. The chainrings don't shift as well, I have a SRAM eTap drivetrain which was always perfect with the SRAM crankset but is intermittently temperamental on the oval chainrings. Finally, the chainrings are noisy with a dry lubricant, but a heavy wet lubricant eliminated most noise.

BTW: Most current oval rings are are significantly different from Shimano Biopace design. I've ridden both, they are not in anyway comparable.

Personally, I don't recommend the Absolute Black chainrings unless the user wants to change the gearing to help on steeper climbs if the bike has rim brakes. The benefits on flat roads at a higher cadence are minimal. The installation and shifting problems are significant.
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Try this Rotor site. It shows the various teams that use Rotor, in on way or another.

https://rotorbike.com/athletes/

It's a 20-year elipitcal cycle.

My 1984 Nishiki International came with them. I replaced the smaller front ring with an even smaller round ring. I shift between the two and don't notice any difference, nor am I aware of anything different from my other two round-ring bikes. But that's not to say the oval rings make no difference, it's just that I don;t notice one.

Love, love, love Absolute Black oval rings. They feel fantastic to pedal.

Unfortunately I could not get the 46/30 ovals to shift well with an 11-42 MTB cassette on a road bike. This setup is completely out of bounds, way beyond what any manufacturer supports and the ovals were just a bit too much. I went to round rings and they shift better but I'm saving the ovals for another project because they feel so great to pedal.


-Tim-

Some dude named Chris Froome uses asymetric chainrings. Seems to work for him when he's not crashing.

I have an old Biopace road double on my Trek 5900, the standard 130 bcd 52/42 set. I like the small ring effect on climbs. Seems to mesh with my less-than-smooth cadence. I tend to pedal squares when climbing. But I'd prefer a 38 or 39T small ring. I'd have to go to a 110 bcd crankset to get a ring smaller than 40 or so.

Can't tell any difference in the 52T, but that may be operator error.

The Biopace really aren't radically different from round, so don't expect a big difference. And it doesn't cause any shifting problems on my bike.

I prefer to spin around 90 rpm and the Biopace seems to thwart my natural cadence. So I'm trying to modify my style a bit on that bike and pedal around 60-80 rpm.

There's a theory that the Biopace rings should be re-oriented for some cyclists, depending on where their power stroke begins. I'm going to try that and see how it feels.

But as the newer makers of oval/asymetric chainrings usually say in their promotional material, they don't like to have their products compared with Biopace.

This is a good point.

Modern ovals and Biopace are 90° out of phase from each other.


-Tim-

I use one and love it
i do feel more powerful and faster maybe BS but I think it is helpful
many pro’s use them

Not much diffeence in my opinion but I'm not a real fanatic.

I used the Rotor oval rings for awhile and I liked them meaning they felt good. I quit using them because of problems shifting the chainrings, power readings slightly off and different from my track bike. In reality, it took a couple of laps on the track to adjust from the oval rings but my thinking was why train on oval rings on the road with the goal of racing on the track.

I would not reject them out of hand and I think they are athlete specific. And of course, if you think you are better off with them than without them...you are.

I have Wolftooth elliptical rings on my mtbs and they make a slight but unmistakable difference in smoothing my pedal stroke and adding a bit of oomph to climbing. I like them a lot.

I have 28/36/42 Biopace rings on my 1989 LHS Montana Summit. (originally 28/38/48 I changed out the middle and big rings. My "racing days" ended roughly 15 years before I was born.)
My knees and hips don't hurt as bad after riding the KHS as they do riding a bike with round rings (and comparable over-all gearing) over the same route and distance.

Modern oval rings aren’t the same as Biopace.

Since my July post I've experimented with re-orienting the alloy road style Biopace 52/42 double. With the typical 5-bolt pattern we're limited to shifts of 72 degrees.

The 42T small Biopace didn't feel right in any orientation other than the original. It created dead spots that I didn't notice before. And I tried standard round 38 and 39 chainrings in place of the 42 but missed the Biopace. So it's back on the Trek 5900 in conventional orientation.

The 52T Biopace did feel better to me shifted 72 degrees clockwise, viewed from the drive side. It seemed to mesh better with my pedaling style. It's not as noticeable as the smaller 42T chainring which is more eccentric with noticeable elongation of the lobes. The larger 52 is only slightly eccentric, so it's pretty subtle.

And my Ironman still has conventional round chainrings. The only change I've made is to switch from the original Suntour plain 52/42 to Vuelta ramped and pinned 50T big ring and either 38 or 39 small ring -- depends on which freewheel I'm using and the anticipated terrain for a long ride. The Ironman is my easier effort bike, comfortable for longer rides and more casual group rides. I spin more, around 90-100 rpm. With the Biopace on the Trek I concentrate on lower cadence and more effort per stroke.

Still not a radical difference from round chainrings, but I'm tempted to try some real oval chainrings for another bike project I'm building up.

I like BioPace. So did Sheldon Brown.

https://www.sheldonbrown.com/biopace.html

Cheers

I rode with a Sugino Cycloid ring at some point in the '90's on a Cannondale hybrid set up with a single ring. Can't remember if I could tell a difference from round.
More recently, have used one (Cycloid) to create an avatar.

I avoid them. To me, the Oval Tech rings are very noticeable when comparing to BioPace but then these are rather oldschool these days. I avoid them. About 3 years ago I nabbed an ‘87 Miyata with BioPace rings and regarded the changing of chainrings to be factored in with tires, bar tape and cables.

thought "Oval" was a brand, not an actual shape. Live and learn

My Schwinn had a 38T Biopace middle ring, but when I replaced it with a 40, I went for round, which I prefer. (More uniform pedal cadence, and better shifting.)

Whether or not you might like oval or other non-round chain rings is something only you can decide.

FWIW, Shimano spent a great deal of money on ergonomic research to develop their BioPace rings. Unlike most other non-round rings, the BioPace eccentricity changes with tooth count. The larger rings are almost round, while the smallest rings are almost square. They are designed to be used in a certain orientation with the crank arm (there are index marks to line them up), but some people find they prefer to shift them from Shimano's intended orientation. Do whatever works for you. Shimano's assumptions in designing BioPace rings may be different from your own riding style.

Round rings shift a helluva lot better.
Jon

I'd heard some reports of shifting problems with Biopace but haven't had any problems myself, even after re-orienting the 52T ring. But as other folks noted the Biopace chainrings aren't as extreme in eccentricity as others. The effect is pretty subtle.