Moisture

After orienting my small chainring correctly (with the nub underneath the crankarm like someone pointed out) and comparing this to two other bikes with circular chainrings, I have to say that the difference is not drastic. If you didn't know that you got elliptical chainrings fitted, you'd probably not even notice much difference. But the effect does become aparrent if you're the sort that really focuses on timing the 6 o clock position of your pedal stroke correctly.

I've been using my smaller chainring alot more ever since which has resulted in a subtle bump to my pedalling cadence. The small jump in teeth between the two front ratios proves to be very useful for my needs.

If I had to explain what Biopace feels like in a nutshell, the first thing I must note, that if you just mash your pedals without thinking twice about it, you're probably not going to like the way they feel. I don't feel as efficient putting this effort into my pedal stroke on a bike with circular chainrings. Youre required to sort of mash through the powerful part of the stroke and accept the slight drop off in power as the pedal spins back up without biopace.

With the biopace crank, its carefully designed around a near identical speed of the crank regardless where in the stroke you are. Near impossible to do with circular chainrings. I don't see anything wrong with using these even if you are the sort to spin fast.

I feel like I am being scolded unless I am putting in some sort of effort into maximizing the efficiency of my pedalling. Felt lumpy at first until I got used to it.

Kapusta

That is the idea behind modern oval rings.

BHays

Wiggins and Froome.

tomato coupe

Wiggins went back to round rings ...

mplsbiker

So I am not a trolling expert, but it seems just based on this quote alone that there is still a lot out there for you to learn, or maybe you are just doing this for your own laughs. That is totally fine, who really cares.

On a serious note, if you are indeed serious; I have many failed bike projects under my belt, but I guess every time I learned something that made me a better rider or mechanic I never really felt the need to take to the internet to start preaching to everyone about something that i just learned that they have probably known for years. Setup your rings right, go ride them, have fun and move on.

canklecat

33". Technically 175 cranks are fine. But with age (63), loss of flexibility and cumulative injuries I occasionally feel twinges in my knees, hips and lower back with longer cranks. When I switched to 172.5 cranks with round rings, and 170 cranks with Biopace, it felt much more natural.

And I work a lot on physical therapy. Last month I resumed longer walks and jogging for the first time in more than 30 years. But I still prefer my knee/thigh being angled at the top of the stroke, never horizontal with the ground. I know some younger, stronger riders do better with a slightly lower saddle position and more extreme knee/thigh flex, but I can't do that anymore. I have to limit my knees' range of motion to prevent injury, so my saddle is a bit higher than usual and I prefer shorter cranks to reduce knee flex. I'll never have anywhere close to the power I had even five years ago, so I'm mainly interested in preventing injury now.

A bit of a digression, but for years there have been theories about longer cranks being better for "torque" or "mashing" but there's no evidence in lab tests to demonstrate this effect. In recent years Greg LeMond has talked about changing his earlier views on theories about crank length.

Two of my bikes still have 175 cranks but I plan to change everything to 170 or 172.5. I'm hesitating on one bike only because it has an Ultegra Hollowtech crankset and won't be cheap to replace. My other bikes are all square taper BBs and I have plenty of spare cranks and chainrings in various sizes, so swapping is easy.

Slightspeed

Mazda rotary engines rotate on an eccentric center to allow the rotor to rotate thru the combustion stages.

Reynolds 

Cams?

Bimmer69

I'm a casual rider - maybe a couple hundred km per week when the weather is decent (above 15C and no rain).
Both my Miele's have biopace rings. Can't really tell the difference except when climbing hills. It seems a bit easier vs. a couple other bikes that have standard circular rings.

slowguynz

I have a 30t Absolute Black oval chainring on a 1x11 MTB. I'm 61, and climb a lot of steep trails.
I have no scientific argument to offer, but my knees and lungs both seem to like it.

unterhausen

When was biopace discontinued?

I would be interested in other reviews of contemporaneous products from 1985, such as the top TV from 1985. Which was a sony trinitron. Might actually be a nicer picture than nowadays, but a high-end TV back then was less than 30"

Moisture

Biopace discontinued when Shimano realized that investing a huge amount of time and resources into designing chainrings designed to work naturally to your inputs was disregarded by everyone who didn't wish to put a little bit of effort into perfecting their pedal stroke.

Or maybe everyone was simply so good at pedalling that the cranks effectively moved at one constant rate throughout the entire revolution and Shimano grossly misinterpreted the sheer capabilities of flabby untrained old men riding bikes.

Moisture

They must help smooth out the power delivery on the steep climbs and help set you into a more effecient pedal stroke

Koyote

Or maybe his knees and lungs just prefer extremely low gearing on climbs?

Koyote

You could get one that was larger than 30"...But did you ever have to move one? They were soooo heavy, and the shape -- with that huge picture tube -- made it awkward even for two people to move around.

But still, a Trinitron, at least in its time, was a better piece of equipment than those silly oval chainrings the OP is carrying on about.

slowguynz

Haha no doubt they do. How unusual...

I do find most of my contemporaries end up walking up the steepest sections I can ride.

Due to careful use of a gear calculator when building new bikes, I can also report that my MTB lowest gearing (as in metres of development, not just gear ratio) has purposely remained exactly the same since 2004. Given that I've aged a bit over that time, and yet am still riding the same steep sections, with perceived less effort and less knee strain, I'm prepared to say that the oval chainring I've been using for the last 4 years is more than just marketing fluff.

Or maybe it's all in my head. Either way, I'm happy.

Reynolds 

"Oval chainrings have been around, on and off, since about 1890. The fact that they aren't in general use tells me that there's no advantage in using them.
Generally, there's a fad for them every so often. A few people like them, but not enough to sustain their general availability, so after a few years they are gone until the next revival."
(Taken from another online debate about Biopace)

kayakindude

Currently using the Biopace on my first indoor trainer. Bike was in storage for 12 years and honestly do not feel any difference (both feel smooth and natural) in pedaling between that and the tandem we still use when conditions warrant.

The only thing I found odd was that after 2 weeks on a trainer it seemed easier pedaling outside. I think that is more trainer resistance than Biopace.

Happy Feet

I have a couple of bikes with them, and several more without. Also find no difference.
The only time I think of Biopace is when the occasional poster says they are taking them off their bike because they are substandard to which I think... no difference really. I wouldn't remove or add either way.

shrimp123

since there are a bunch of biopace users..... anyone have need for this? its in my bin and i have no crankset that can use it.


biopace chainring

Kapusta

The less someone understands about the differences between different "oval" rings, the more this sounds reasonable.

However, the functional difference between Biopace and the current generation of oval rings is actually much greater than the difference between either one and round rings. In other words, modern ovals perform more like a round ring than they do like Biopace. And vice-versa.

Modern ovals are currently doing quite well in the MTB market. Many companies selling them and they are generally well received.

Moisture

According to the nub which shows where the pedal is supposed to be oriented, you can clearly see the ring js largest at the 3 and 9 o clock position.

mplsbiker

What is the BCD on that ring? I would gladly take it.

shrimp123

not sure how to measure BCD.... but here you go

shrimp123

and here is the back side for all to lust about