Oval Chainring-Is It Worth It?
 

Does it help with speed, climbing, etc., or just a waste of money?

I am generally pleased with the asymmetric ring on my 1X bike, but I'm really curious to hear the opinions of people who have never used one, which I'm sure we'll get plenty of.

I would genuinely say that the oval ring has helped my pedal stroke overall, but most notably on my round-ringed 2X bike-- much smoother now.

So I see it as a training tool. I don't think I'm climbing any faster or riding any faster. At least not to any degree directly related to the chainring.

I'm planning to try a newer design oval, eccentric or asymmetrical chain ring setup this year. Hadn't planned to but last year I bought an older Trek 5900 carbon fiber road bike frame from a friend and he remembered that I'd mentioned being curious about Biopace. So he brought the bike set up to ride with good older Shimano 600 and comparable components taken off an Ironman.

Turns out I actually liked Biopace. But only with 170 cranks -- more about that below.

Before the nitpicking begins, Biopace are technically eccentric or oblong, sort of a squashed square in the smaller rings. The larger 52T ring is just slightly asymmetric and doesn't feel much different from round. But the 42T smaller ring feels different.

I rode that bike about 2,500 miles last year, no problems. The smaller ring felt a bit pulse-y or surge-y on climbs, but I adapted quickly. And, just as Shimano suggested years ago, I found it worked better for me with a slower cadence. With round rings I usually spin at 90 rpm like clockwork. With Biopace I experimented with mashing bigger gears and found my sweet spot was closer to 75 rpm average, as slow as 60 rpm on seated climbs, and in the 40-50 rpm range when standing to stomp the pedals. There was a slight sensation of improved leverage. And slowing down smoothed out my sometimes raggedy cadence.

The main advantage I noticed was my heart rate didn't peg so quickly. At 90 rpm on climbs my HR would jump to 160 or higher. At my age (62) that's pretty close to redlining. With Biopace and a slower cadence my heart rate stayed in a sustainable range at the same perceived effort and average speed.

My climbing improved a bit, although that may have been due in part to the lighter carbon frame. The bike weighed about 20 lbs total, including pedals and tires, compared with 25 lbs for my steel bike. Made a difference on climbs. And I set the carbon bike up slightly more aggressively so the lower, more aero position was probably a factor too.

And some folks prefer to change the factory orientation of the elongated lobes. I tried both ways and didn't notice much difference on the big ring, but the smaller ring felt weird in any position but the original orientation. With only 5 bolt holes re-orienting is limited. Some newer oval, eccentric, etc., chainrings have multiple bolt holes to finesse the orientation and where the down stroke engages the elongated lobes.

The only problem I had occurred when I took that Trek 5900 out of service to repair the headset, and decided to move the Biopace rings over to my Centurion Ironman. Within a week I was feeling knee twinges and slight aches -- unusual for me. After a couple of weeks I was really concerned. I made several tweaks -- saddle height and fore/aft position, stem height, chainring re-orientation -- but nothing helped.

And my cadence felt more raggedy than ever. The pulsing, surging sensation with Biopace was exaggerated and distracting.

The only remaining difference was the cranks. Instead of moving the entire Shimano 600 crankset with 170 cranks over to the Ironman, I put the Biopace rings on the Ironman's Suntour GPX crankset with 172.5 cranks.

So I swapped the entire Shimano 600 crankset -- 170 cranks, Biopace rings in factory orientation -- over to the Ironman. Problem solved. The knee twinges cleared up and I felt that forgiving sensation of my raggedy pedal pressure. I tend to stomp and have never really mastered the pedaling in circles technique. Non-round rings seem forgiving of that quirk, for me at least.

Surprisingly, for me at least, Biopace was very sensitive to crank length.

I'm not sure whether that would translate to other non-round chain rings, but it's worth considering.

My bike cranks range from 170 to 172.5 to 175. But I'm seriously considering switching them all to 170. FWIW, I'm 5'11" with 33" inseam and thigh length a bit longer than normally proportional. That might be a factor in optimal crank length, at least with non-round rings.

Short answer: no it doesn't help
Long answer: it doesn't help with climbing, speed or anything else

is it worth it? If you like it and get some sort of placebo boost then sure

The fact that some people prefer circular rings, others prefer ergonomics-oriented oval rings (BioPace), and still others prefer power-oriented oval rings just goes to show that one kind isn't perfect for everyone and you'll have to find out for yourself.

The research evidence seems to show mixed results, with no clear evidence that they either help or hurt. Some riders like the feel, others don't. What this means is that you can be free to choose whatever feels best for you without worrying that it will penalize your power output. If you like (or dislike) the feel you can switch and ignore what anyone else thinks. Just tell others to go to hell and keep their opinions to themselves. That's what I do. It's liberating.

Canklecat's post above is the best I've ever read on the topic of BioPace chainrings. Should be a sticky.

It's possible that the currently available oval rings---Rotor, etc.---work for at least some riders who maintain a high cadence; but as RChung notes in his post, there doesn't seem to be much in the way of convincing evidence one way or the other concerning that design. Oval rings oriented like the Rotors have been around since at least the 1930s but never established a permanent presence in the market, so there's that.

Common sense tells you that you want the chainring oriented such that the gearing is highest where the strongest muscles are recruited. Shimano's engineers, unlike the people at all the companies that have introduced oval rings designed as common sense would seem to dictate, actually researched the ergonomics of pedaling.

Knowing that legs evolved to run at maximum efficiency using a brief foot strike followed by a comparatively long rest during each stride, Shimano's engineers designed BioPace chainrings to facilitate similar efficiencies of pedaling: lower effective gearing (reduced load) and reduced time spent where the stronger muscles are recruited, higher effective gearing (increased rest) where essentially no work is being done. Brilliant, really.

At the time when BioPace was introduced, Shimano had not yet figured out how to explain such subtleties to their American market. I think it might have been just before they hired Wayne Stetina at Shimano USA. Those of us who were around in the bike scene in those days can remember what happened next: the bike magazines praised BioPace at first but then, after the magazine writers started hearing complaints from bike racers that BioPace felt weird for high-cadence riding, and especially for sprinting, they began dissing BioPace.

Shimano's insisting that any bike manufacturer who wanted Shimano groupsets had to accept BioPace cranks didn't help their relationship with the manufacturers. The bike sales reps then complained to bike dealers. Net effect: the market went from everyone wanting BioPace to no one wanting BioPace.

After the backlash, Shimano quickly released BioPace II, which is a watered-down version of the original design, but by then the damage had been done.

Too bad. BioPace was really designed for sport riding at moderate cadences, which describes the way many riders ride.

There are very successful pro riders using them, but there are also very successful pro riders that don't use them.

Chris Froome uses some sort of eccentric, asymmetric chainrings -- dunno if he still uses Osymetric, which appears closer to Biopace than oval, with squashed, squared off ends. Team Sky/Ineos has always been pretty tight lipped about specifics regarding their marginal gains approach, and Froome is a savvy guy who, in interviews, only acknowledges that he likes the non-round rings, but I've never heard him share any specifics about how they know it offers some advantage.

And you know Sky/Ineos have measured, quantified and calibrated every possible thing to the nth degree. So unless Froome simply means he likes them because it feels right, and Sky/Ineos just go along with that to keep him happy, it's likely there is some measurable advantage... at least with him. It would be interesting to see some power data for both feet/pedals but I doubt that will ever be made available while he's still an active racer.

Froome has almost always appeared ungainly and awkward on bikes (other than time trials where he looks pretty smooth when he's not crashing). That includes his pedaling stroke, which looks kinda choppy even at higher cadence (compared with, say, Phil Gaimon, who's pretty smooth at high cadence). So maybe that's the key to why some folks like eccentric chainrings and others don't -- how smooth or ragged their cadence, whether we're pedaling circles or squares.

I don't have a power meter, let alone something to measure both legs and full stroke. Those cost more than all my bikes put together -- I'm such a cheapskate, I've never spent more than $200 on a bike. So I have no way of measuring whether I'm getting any benefit from Biopace. But it feels right once I have it tweaked to my liking (and today's 26 mile ride with lots of headwind was a good test). And I definitely have a choppy pedaling style, alternating effort depending on how my lower back, hips and legs feel. Sometimes I put more effort into the right foot, sometimes the left. With the Biopace rings it feels a bit more even than with round rings.

The Elevate browser extension for Strava shows that over the past three years my climbing speed has improved a bit, particularly last year when I mostly rode the old Trek 5900 with Biopace rings and 170 cranks. And I'm pretty close to that on heavier Ironman with the same crankset.

But it's all very subjective. I'm just gonna go by feel. If my knees are happy, I'm happy.

It has piqued my interest in trying a newer non-round chainring. I might check the various online discounters, see if they have something in my budget (like, $50 or less -- I did say I'm a cheapskate), and give it a try on a new-to-me bike build with a Diamondback Podium frame. It came with a nice Ultegra crankset but I'm not sure I'll get along with the 175 cranks.

I've got a couple that I'm putting up on eBay, so I'm gonna say they are amazing! Will definitely make you faster!

On a serious note I did not see a performance difference good or bad, just a couple rides adapting to the feel, then same old numbers & TT times. I know a couple of very fast racers who ride Q-Rings and are happy with them. I wanted them to work, they just didn't.

Everything I've ever read or seen seems to be n=1 type data. If there were a significant advantage across the board I've got to believe everyone would be racing on them.

I tried Rotor Q rings. The change reminded me of when I got a new tennis racket or golf clubs. There seemed to be a bump in performance and then the old me emerged. I did some hill climb races and thought I was slower. That is the kiss of death to any change.

Since I am a trackie, and oval rings are not feasible, I thought why develop any neurology that is different on the road?

The oval rings change the gearing slightly and crank based power meters are off about 3% due to the change in tangential speed of the oval rings.

Also, shifting was never great on the front derailleur.

I took them off and still have them. Occasionally, I think about trying them again. I talked with my mechanic about putting them on and he had a look of terror in his eyes at the thought of adjusting the front derailleur to work properly.

Try them and see if they work for you.

Interesting reading the items so far, I sense a rather distinct lack of enthusiasm for them on the part of actual owners. I wonder if you wouldn't get a more ringing endorsement if you were to ask about, say, "Red bikes".

One aspect I did not mention which is the reason one should try them, is the ability to apply more torque to the crank arm when the leg is in the best position to generate force. One can adjust the Rotor Q rings to exactly where one can apply the most torque. It is similar to having a cam on the weight machines in the gym to match the degree of difficulty to muscular capability. This sounds so right, it has to work.

Unless it does not.

I ride both round and oval chain rings on my various road bikes. After many years and lots of miles on both, here are the differences I have detected. After really long rides, 80 miles or more, I find my knees feel a bit less achy on oval rings. Toward the end of those same rides, I think my legs feel a bit less zapped with oval rings. I have never detected a speed, sprinting or climbing difference based on which rings I ride.

^^^ This mirrors my experience. I also think there's something to the notion of "recruiting different muscles" through somewhat different pedal strokes. I just know that at least to my perception (feel) I am fresher after multiple back-to-back days when switching back and forth between the oval-ringed bike and the round-ringed bike. So as a rider not obsessed with seconds off of a TT time, and more about enjoying ride 5 of the week just as much as ride 1, less fatigue is worth the price of admission.

But I've never used oval with a front derailleur, so there might be something to that. Bike shifts exactly the same as it ever did. If I had to time my shifts on my front rings like an old diesel tractor, I would likely feel differently.

I rode original BioPace for quite a while as a commuter, but I was more of a masher then than now. I thought they were great, even though the differences seemed so marginal i often wondered if it was placebo or real.

I did feel like the oval rings smoothed out my pedal stroke, and since I was always carrying fair-sized loads, that help was much appreciated.

After reading @canklecat's excellent review and those following ... I wonder if I should drag out the old set for one more try, or if my new, smoother stroke would negate any benefit.

Honestly, like Cankle, I wouldn't buy another set unless i saw them (with 175-mm cranks) for very little money ....

As for the newer designs designed to increase power .... when I only occasionally crack triple digits in wattage, I cannot see the point.

This one says no, don’t make a difference at all...

“During the incremental exercise test, no significant differences were found in power output, oxygen consumption or heart rate between oval “Q-rings” and conventional chainrings”

“Over the course of the incremental test, blood lactate levels were comparable for the oval “Q-rings” and conventional chainrings”

“During the short sprints performed after the incremental test, there were no statistical differences in power production between oval “Q-rings” and conventional chainrings” - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3990898/


This one says yes, but only in max sprint power and only at high cadence...

“The Osymetric non-circular chainring significantly maximized crank power by 4.3% during sprint cycling, in comparison with a circular chainring.”

“This maximal power output improvement was due to significant higher force developed when the crank was in the effective power phase.”

“This maximal power output improvement was independent from the shoe-pedal linkage condition.”

“Present benefits provided by the non-circular chainring on pedalling kinetics occurred only at high cadences.” - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4879434/

I’ve never tried them, no interest. My pedal stroke is fine, no knee pain, feel great on my plain old boring chainrings.

Dear Abby,

My mother told me my oval chain rings were stupid. I told her to go to hell, but now she won't do my laundry anymore. I don't know what to do. Should I switch chain rings or just wear dirty clothes?

Chris from England


Dear Chris from England,

Your mother should keep it to herself. Learn to hand wash your kit.

Abby

Ditto. It's not so much a consistent, measurable difference in speed, power, etc., but in feeling less fatigued. As I mentioned above, the non-round, not-quite-oval Biopace rings encourage me to slow my cadence without losing speed, which definitely lowers my heart rate compared with spinning. While I'm more comfortable spinning around 90 rpm -- mostly because it just seems to mesh with my natural internal rhythms -- it'll peg my heart rate quicker on climbs. When I consciously keep my cadence a bit slower, push slightly harder gears, and watch my heart rate, I tend to feel less exhausted after my usual workout rides on the same route.

And the last time I consciously tried to push my limits on the old Trek 5900 with Biopace -- mashing harder gears and pushing my heart rate to the max sustainable limit -- I set my fastest times along a 35 mile roller coaster route, on a warm night with neutral wind, just a slight breeze.

Reminds me, I gotta fix the headset on that bike (old Chris King headset, appears to be titanium, finally needs new bearings after 27 years and zero maintenance). It's not radically different from my Ironman, but about 5 lbs lighter and possibly even better on chattery chipseal for comfort. It was just a pleasure to ride, with those 170 cranks and Biopace rings. I sorta prefer the Ironman as a casual cruiser, with 50/38 or 50/39 round rings and 13-25 or 13-28 freewheel. I can't get much top end speed on fast downhills without spinning out, but that bike is a joy to cruise all day at 15 mph and for casual group rides.

Yup, I'm considering a Biopace triple for my old Univega, an early 1990s MTB-lite that I've hybridized and citified with Nitto albatross bars. Nothing wrong with the original 50/40/30 round triple, but I just recently discovered the mountain bike Biopace triples were also available in aluminum alloy. For years I'd heard they were only available in steel so I avoid them. But If I can snag a set and mate it with 170 cranks, it'll be a fun experiment.

I have zero scientific proof, but my suspicion is that for most cyclists, you adapt and it makes almost no difference.

However, I am sure there are SOME cyclists where it strikes a resonant chord in their physiology and makes a real (but again, likely very modest) improvement. I suspect Froome falls under this category.

Similarly, there are some cyclists where it strikes a dissonant chord in their makeup and makes real difference for the worse.

I would not bother. Again, zero science here, but I read a lot.

Actually, they haven't -- but they like it when others think they do.

A harder 35 mile ride Sunday afternoon seemed to confirm my impressions about how Biopace works for me. I've swapped the entire crankset over and copied, as closely as possible, the fit from the Trek 5900 to the Ironman. The Saturday 25 mile zone 3 ride indicated no knee problems.

Sunday I pushed my zone 4 as much as possible, got my fastest overall time/average speed on that familiar 35 mile route this year on a heavier bike than my previous best times. Leg muscles are cooked but no knee problems. Same kit as my previous best time riding the Trek 5900, to reduce variables (same wheels with 30mm profile rims, shoes and pedals, bibs, snug jersey but not skinsuit-tight, cheap aero helmet with magnet mount visor).

I still would have done better on the carbon fiber bike. I could feel the weight of the Ironman on hills. And the downtube shifters are a bit less efficient -- on hills if I miscalculate gearing while standing to stomp up climbs, I have to sit for a moment to shift, then stand again. Brifters are more efficient.

Now I'm gonna go take a more serious look at oval/eccentric chainrings for another bike build...

Chugging Gatorade (the one with a lot of sugar) half-way through my ride usually boosts me :)

i say yes love mine. not sure if there is huge benefit but i think i am morr efficient.