asgelle

I'm sure yours is even though every study ever conducted found the most efficient cadence to be around 60 rpm. (or perhaps that word doesn't mean what you think it means.)

TiHabanero

Oval rings have been in development since at least the 1930's. Shimano was the first commercially successful company to market them, but of course they were the first company to make them commercially available on a wide scale. Before them they showed up on production bikes, but were rare. The arguments for the ring design has not changed over the years as has the public's reception of them. There is no question that they do help some people, and harm others. There is no one size fits all in this world.

Kapusta

It is clear that some folks posting here are not aware of how oval rings are being received in the MTB world right now.

Discounting oval rings because of your experience with biopace is like discounting full suspension because of your experience with an old URT design.

rosefarts

I never cared for it.

Looking through my parts bin today, I needed a chainring on which to build a wind chime from. The choices were 10 speed Campy or from a 6 speed Biopace that I upgraded for my wife (52/42 bp to 50/38 round).

The big ring is pretty round actually.

It'll be nice hanging on my back porch.

Moisture

So what the hell is this nonsense with ridiculously high pedaling cadences about?

Moisture

Sure it is.

i was going to ask you to explain, but there's.nothing to explain.

asgelle

Speed, fatigue resistance, acceleration, a lot of things, but not efficiency.

Reynolds 

Most world hour records were achieved at over 100 rpm.

Paul Barnard

Is this a good place to talk about down tube shifters being the fastest?

Unshore

I liked the biopace small ring for climbing, for bridging gaps and sprinting I liked the smooth spin of a round ring

rosefarts

He said the argument for the rings hasn't changed, that they help smooth out our (bipedal human) energy curve.

What "clocking" or eccentricity is needed to do this changes depending on the individual companies marketing them.

HerrKaLeun

Timely review, only 30 years late.

what other 1980 technology is not so great these days? I heard the Commodore 64 has problems with 4k displays. A review should be done.

canklecat

Biopace worked for some of us. I used a 52/42 set almost exclusively throughout 2019 on one road bike. It needed only a few tweaks to suit me.

With 33" inseam I can handle cranks up to 175, but Biopace rings felt best to me with 170 cranks. I felt knee twinges with longer cranks. Even 172.5, my usual preference, wasn't quite right with Biopace. Switching back to 170 immediately felt better.

And it worked better for me with slower cadence. I usually spin around 90 rpm but with Biopace it felt better to crank around 60-75 rpm, tops, and push harder gears. I got so accustomed to it that when I switched another bike back to round rings and longer cranks this year I had to relearn to spin. (Which isn't necessarily more efficient for everyone anyway. It was mostly a thing to promote quicker recovery between stages on long tours.)

The more oval/eccentric smaller 42T Biopace ring felt more like my other bike's 38 or 39T round ring. It can fee a bit surge-y at first, but I got accustomed to it.

I tried the trick of re-orienting the Biopace rings to other positions -- very limited with the typical 5-bolt spider -- but eventually returned to the Shimano factory standard positions. There may be some benefit to re-orienting other oval/eccentric chainrings that offer more bolt hole positions. But Shimano's theory seemed to be about right for some folks.

I also tried mixing 50 and 52T round rings with the Biopace 42T, and vice versa, but resumed using the full 52/42 Biopace setup. It shifted better. And the 52T Biopace is only slightly eccentric so it didn't feel dramatically different from round rings. The smaller chainring felt different, and worked well for me on climbs after I changed my cadence to push harder gears slower. My legs got stronger over 2019 and carried over to 2020 even now that I've resumed using mostly round rings and spinning more.

I'd consider newer types of oval/eccentric rings, at least for one of my bikes just to experiment a bit.

tomato coupe

Here we go again ... the total newbie telling everyone else how cycling works. Give it a rest, please.

rosefarts

[QUOTE=HD3andMe;21803868]Please pay attention.
[​​​​​/QUOTE]

You're being an ass. I card you on in and you doubled down.

The argument for oval rings is the same as it always has been.

The execution of it, ring shape and position and whatever else you want changes.

What are you even arguing? That Absolute Black or whatever have a different intended purpose than Biopace?
Nope, same purpose, different design.

Miele Man

Sheldon Brown liked BioPace. He wrote an asticle about them. John Allen has revised it. I don't know how much of the article is still Sheldon's views.

https://www.sheldonbrown.com/biopace.html
From that article:

"Biopace is a patented non-round chainwheel design made and licensed by Shimano. To a casual glance, Biopace chainwheels resemble elliptical chainwheels, but on closer examination they turn out to be the opposite of the classical elliptical design. The product of extensive research and computer-aided design, Biopace chainwheels have the small radius engaged when the cranks are horizontal, the large when they are vertical. This is because the Biopace design is based on a dynamic analysis of the motion and momentum of moving cranks and legs, unlike the static, geometric analysis that produced classical ellipticals.The theory is that during the power stroke, when the cranks are more or less horizontal, you are using the power of your legs to accelerate your feet, which get going quite fast in the lower gear provided for that part of the stroke. The momentum of your feet then carries the pedals through the "dead spot" when the cranks are near vertical. Since the rider doesn't push as hard during the power phase of the stroke, and motion is slower when the leg is changing direction, the Biopace design is gentler on the knees than even round chainwheels."

and

"What Are They Good For?

Biopace chainwheels are particularly suitable for touring cyclists and time trialists, or any application that involves a steady, fairly constant cadence. They allow healthy, efficient pedaling at slower cadences than is possible with round chainwheels. They are especially suitable for triathletes and mountain bikers. The triathlete benefits because the motion is a little bit closer to that of running, making the transition easier.

The mountain biker particularly benefits, because the Biopace design somewhat smooths out the delivery of power to the rear wheel. In climbing on loose surfaces, the limiting factor is often traction. The rear wheel tends to break loose during the maximum power phase of the pedal stroke, wasting most of the cyclist's energy. The Biopace chainwheel works like a storage device, storing power during the main power phase of the stroke as the feet accelerate, then delivering the stored power to the rear wheel during the "dead center" phase when the cranks are nearly vertical. The same average amount of power is delivered to the rear wheel, but in a smoother, less pulsating flow. The bicycle moves at a more even speed. All the energy is used to propel the bike forward, without the high-power peaks' spinning the rear tire or causing the bike to "wheelie."

and
"

"The Cadence Issue

The marketers of Biopace made a crucial error of judgment: too much information. In particular, they mentioned that the Biopace design was optimized for cadences of about 90 rpm and slower. Many readers interpreted this as an indication that Biopace chainrings would somehow interfere with pedaling faster than that. This perception caused a bit of a self-fulfilling prophecy, and the Conventional Wisdom arose that Biopace was bad for high-performance cyclists for this reason. I [Sheldon] used to believe this myself, but I rode them anyway because I appreciated their other virtues.

In 1989, Shimano introduced a new variant, Biopace HP (High Performance), more nearly round than standard Biopace. This was marketed to cyclists who race in packs and use clipless pedals, but did not overturn the marketing problem.

Among other bikes, I run Biopace on several of my fixed-gear machines, where high cadences are quite common in descending hills. In practice I have found no less ability to spin fast with Biopace chainrings, and, if anything, they permit me to spin faster without bouncing in the saddle.

Here's why: While your feet go around in circles, your legs basically go up and down in a reciprocating motion. With Biopace chainrings, your leg speed is faster in the middle of the stroke (when the cranks are horizontal) but slower at the top and bottom of the stroke (when the cranks are vertical.)

The slower motion at top and bottom means that your leg changes direction from upward to downward, or downward to upward motion at a slightly slower, more gentle speed. The increased leg speed near the middle of the stroke is the result of a more gradual acceleration/deceleration with the leg moving in the same direction. Bouncing in the saddle generally results from difficulty with changes in leg direction, not speed in the middle of the stroke. Thus, as Biopace makes it easier on your knees, it also can help you spin faster without bouncing!"

Cheers

Trakhak

The points made by Sheldon Brown and John Allen in Miele Man's post above seem irrefutable to me, but we'll see.

Moisture

This is what I find really helpful about these cranks.

First off, they naturally change the way you apply power to the cranks. They require you to be smooth and work more precisely with the power curve to get the most of then. Plus, they are rather strict with ensuring that you maintain this certain cadence which just so happens to be the most efficient RPM when it comes to cycling. They don't seem to feel too bad spinning at a relatively higher cadence, but their particularly unhappy with going too low which seems to cause this lumpiness.

I find myself wanting to find the right cadence which really smooths out that power delivery and optimizes the efficiency. I think it's really helpful with making you a better biker.

Kapusta

You are making the same error here as the first time you wrote it:
The current iteration of oval rings are not failing.

EDIT: Wait, you are not the one who originally said that the first time.... OK, now I'm totally confused. I don't know if you were agreeing or refuting it. So, never mind.

reconnaissance

I’ve been running biopace chainrings on my mountain bikes since they were introduced. Find them easier on my knees and better for climbing where the leg is nearly maxed out. Next am going to experiment with one on my fixed gear bike.

Kapusta

These finer points (which make AB rings a completely different product from Biopace) are lost on most of this crowd.

Kapusta

Here is me trying to explain that modern oval rings (e.g., Absolute Black) are not the same thing as Biopace...

Me "New oval rings are not the same thing as Biopace"
Them: "But, they are both oval"
Me: "The clocking is different... the increase and decrease in gearing happens at different points in the pedal stroke and therefore work very differently"
Them: "But they are all oval. Same thing, just different marketing"
Me: "Biopace was not actually oval"
Them: "Close enough, same thing"
Me: "Have you ever ridden a new oval ring like Absolute black?"
Them: "I rode Biopace 25 years ago, and did not like them so I know I don't like oval rings"
Me: "But these don't work the same way"
Them: "They are all oval. Companies keep trying oval rings and they keep failing"
Me: "They are not failing, oval rings have been well received in the MTB world for a few years now. And that is because they do not work like Biopace rings"
Them: "But they are all oval, same thing as Biopace"

And so on, and so on.....

Paul Barnard

Please excuse this momentary aside. I really do hate to sidetrack a productive thread. Does the name of the component company "Oval Concepts" bother anyone else. They literally make nothing that is oval in shape. Seriously, who in the trailer park hell names wheels "Oval" anything?

JohnDThompson 

People use "oval" as a synonym for "non-round" when describing chainrings. Biopace rings are neither round nor oval, but were designed after biomechanical analysis of pedaling. As with all design and analysis, certain assumptions were made about preferred pedaling styles and their purported benefits. If your pedaling style is similar to those assumptions, you'll probably like Biopace rings. If not, you may dislike them, or prefer "clocking" them in a different manner than what Shimano intended. The vast majority of people actually seemed indifferent to what Biopace offered, and as a result it never prospered in the market in the manner Shimano had hoped.

Moisture

XD so what is the difference then?

yes, I know I read that Biopace works different from the original idea. But looking at the crankset with the chainrings correctly oriented, I can clearly see the teeth count increasing as you move the arms down vertically from the top.