Non-Round Chainrings compared

On Tue, 27 Mar 2007 05:17:00 -0500, DougC <[email hidden]>

Quoted message said:

Long story short: I decided to try some Rotor Q-rings.

I noticed that some people (on one forum I frequent) kept comparing
Q-rings to the various other non-round chainrings they'd had in the
past, and I got curious as to how different all these different rings
were so I decided to trace a few of them on one image. So far I've got
Rotor Q-Rings, O. Symetrics, Bio-Pace, Sugino Cycloid and SR Ovaltech.

http://www.norcom2000.com/users/dcimper/assorted/inanities/recumbent/oval/chainrings.html

Do you know any others that I don't have yet? (I'd need a decent photo
of them to include them....)
~

I took a look at your diagram and I remembered Bio-Pace rings as being
much more eccentric than you show. So I checked out my chainring
collection and while my Bio-Pace 52 looks a lot like your diagram, the
42 is much more eccentric. I wonder why.

--
jeverett3<AT>sbcglobal<DOT>net (John V. Everett)

John Everett said:

On Tue, 27 Mar 2007 05:17:00 -0500, DougC <[email hidden]>

Quoted message said:

Long story short: I decided to try some Rotor Q-rings.

I noticed that some people (on one forum I frequent) kept comparing
Q-rings to the various other non-round chainrings they'd had in the
past, and I got curious as to how different all these different rings
were so I decided to trace a few of them on one image. So far I've got
Rotor Q-Rings, O. Symetrics, Bio-Pace, Sugino Cycloid and SR Ovaltech.

http://www.norcom2000.com/users/dcimper/assorted/inanities/recumbent/oval/chainrings.html

Do you know any others that I don't have yet? (I'd need a decent photo
of them to include them....)
~

I took a look at your diagram and I remembered Bio-Pace rings as being
much more eccentric than you show. So I checked out my chainring
collection and while my Bio-Pace 52 looks a lot like your diagram, the
42 is much more eccentric. I wonder why.

They were introduced with great fanfare; didn't sell, and wer modified
to be more round, hoping that sales would pick up.

They didn't.

I think I remember Bike Warehouse (? might have become Nashbar by
then) blowing them out for 1.99 or something like that.

John Everett said:

I took a look at your diagram and I remembered Bio-Pace rings as being
much more eccentric than you show. So I checked out my chainring
collection and while my Bio-Pace 52 looks a lot like your diagram, the
42 is much more eccentric. I wonder why.

Yea I saw (and noted) that too.
I'm old enough to have bought a couple bikes that came with BioPace OEM
(after the initial romance had worn off, and they were putting them on
every bike they could just to get rid of them) and I remember that the
little triple rings looked basically diamond-shaped, with rounded corners.

I can't find good pics of all the sizes of all types however.
~

John Everett said:

On Tue, 27 Mar 2007 05:17:00 -0500, DougC <[email hidden]>

Quoted message said:

Long story short: I decided to try some Rotor Q-rings.

Quoted message said:

I noticed that some people (on one forum I frequent) kept comparing
Q-rings to the various other non-round chainrings they'd had in the
past, and I got curious as to how different all these different rings
were so I decided to trace a few of them on one image. So far I've got
Rotor Q-Rings, O. Symetrics, Bio-Pace, Sugino Cycloid and SR Ovaltech.

Quoted message said:

http://www.norcom2000.com/users/dcimper/assorted/inanities/recumbent/...

Quoted message said:

Do you know any others that I don't have yet? (I'd need a decent photo
of them to include them....)
~

I took a look at your diagram and I remembered Bio-Pace rings as being
much more eccentric than you show. So I checked out my chainring
collection and while my Bio-Pace 52 looks a lot like your diagram, the
42 is much more eccentric. I wonder why.

Two things at play here:

1) There were several incarnations of Biopace: Biopace, Biopace II,
and Biopace HP. HP was noticeably "rounder" than the original.

2) In all incarnations, the Biopace "contour" was more noticeable in
the smaller rings.

Ozark Bicycle said:

John Everett said:

On Tue, 27 Mar 2007 05:17:00 -0500, DougC <[email hidden]>

Quoted message said:

Long story short: I decided to try some Rotor Q-rings.
I noticed that some people (on one forum I frequent) kept comparing
Q-rings to the various other non-round chainrings they'd had in the
past, and I got curious as to how different all these different rings
were so I decided to trace a few of them on one image. So far I've got
Rotor Q-Rings, O. Symetrics, Bio-Pace, Sugino Cycloid and SR Ovaltech.
http://www.norcom2000.com/users/dcimper/assorted/inanities/recumbent/...
Do you know any others that I don't have yet? (I'd need a decent photo
of them to include them....)
~

I took a look at your diagram and I remembered Bio-Pace rings as being
much more eccentric than you show. So I checked out my chainring
collection and while my Bio-Pace 52 looks a lot like your diagram, the
42 is much more eccentric. I wonder why.

Two things at play here:

1) There were several incarnations of Biopace: Biopace, Biopace II,
and Biopace HP. HP was noticeably "rounder" than the original.

2) In all incarnations, the Biopace "contour" was more noticeable in
the smaller rings.

I thought they also had road and mountain versions from the start, with
the road rounder/less eccentric and the mtb more eccentric. At least
that's my recollection. Definitely the smaller rings were more eccentric.

Mark J.

DougC said:

Long story short: I decided to try some Rotor Q-rings.

I noticed that some people (on one forum I frequent) kept comparing
Q-rings to the various other non-round chainrings they'd had in the
past, and I got curious as to how different all these different rings
were so I decided to trace a few of them on one image. So far I've got
Rotor Q-Rings, O. Symetrics, Bio-Pace, Sugino Cycloid and SR Ovaltech.

http://www.norcom2000.com/users/dcimper/assorted/inanities/recumbent/...

Do you know any others that I don't have yet? (I'd need a decent photo
of them to include them....)
~

Hi,

Since the Q-Rings folks claim the eccentricity of bio-pace is in the
wrong place, it would be interesting to see where the Q-Rotor "bumps"
are relative (using Rotor's suggested starting holes) to the others
rings, instead of just long-axis vertical.

Joseph

Mark said:

Ozark Bicycle said:

John Everett said:

On Tue, 27 Mar 2007 05:17:00 -0500, DougC <[email hidden]>
wrote:

Quoted message said:

Quoted message said:

> Long story short: I decided to try some Rotor Q-rings.
> I noticed that some people (on one forum I frequent) kept comparing
> Q-rings to the various other non-round chainrings they'd had in the
> past, and I got curious as to how different all these different rings
> were so I decided to trace a few of them on one image. So far I've got
> Rotor Q-Rings, O. Symetrics, Bio-Pace, Sugino Cycloid and SR Ovaltech.
>http://www.norcom2000.com/users/dcimper/assorted/inanities/recumbent/...
> Do you know any others that I don't have yet? (I'd need a decent photo
> of them to include them....)
> ~
I took a look at your diagram and I remembered Bio-Pace rings as being
much more eccentric than you show. So I checked out my chainring
collection and while my Bio-Pace 52 looks a lot like your diagram, the
42 is much more eccentric. I wonder why.

Quoted message said:

Two things at play here:

Quoted message said:

1) There were several incarnations of Biopace: Biopace, Biopace II,
and Biopace HP. HP was noticeably "rounder" than the original.

Quoted message said:

2) In all incarnations, the Biopace "contour" was more noticeable in
the smaller rings.

I thought they also had road and mountain versions from the start, with
the road rounder/less eccentric and the mtb more eccentric. At least
that's my recollection. Definitely the smaller rings were more eccentric.

There was a "road" version in 130mm BCD as early as the mid-eighties.
These might have come under the Biopace HP umbrella, I can't recall
for sure. They were "rounder" than the 110/74mm bcd touring/mtb rings.
I had a set in 52/42 for awhile in ~'86; it was very difficult to
discern the "feel" of those rings from regular round rings.

I bought a set of elliptical chainrings from their designer (inventer?), a
fellow named Conrad Oho, in Marin County. He and I agreed that the Biopace
rings had their long axis going exactly the WRONG way. In your illustration
comparing the various rings, the long axes are shown aligned in the vertical
direction, without regard to the pedal position. I suggest you redo the
diagram, keeping the pedal axis constant.

Conrad Oho worked for Shimano at the time Biopace was being developed.
According to him, the shape was intended to produce a pedal velocity that
simulated walking or running. He also said that the inventor made big
unsupported logical leaps.

The history of Biopace seems to be that the more it was improved, the
rounder it got.

DougC said:

Long story short: I decided to try some Rotor Q-rings.

I noticed that some people (on one forum I frequent) kept comparing
Q-rings to the various other non-round chainrings they'd had in the
past, and I got curious as to how different all these different rings
were so I decided to trace a few of them on one image. So far I've got
Rotor Q-Rings, O. Symetrics, Bio-Pace, Sugino Cycloid and SR Ovaltech.

http://www.norcom2000.com/users/dcimper/assorted/inanities/recumbent/oval/chainrings.html

Quoted message said:

Do you know any others that I don't have yet? (I'd need a decent photo
of them to include them....)

There are the "egg rings" made by Highpath Engineering in Wales. You can
order then in various "egg-ness"es by percentage.

Jim Higson said:

Quoted message said:

Long story short: I decided to try some Rotor Q-rings.

Quoted message said:

Quoted message said:

I noticed that some people (on one forum I frequent) kept comparing
Q-rings to the various other non-round chainrings they'd had in the
past, and I got curious as to how different all these different
rings were so I decided to trace a few of them on one image. So far
I've got Rotor Q-Rings, O. Symetrics, Bio-Pace, Sugino Cycloid and
SR Ovaltech.

http://www.norcom2000.com/users/dcimper/assorted/inanities/recumbent/oval/chainrings.html

Quoted message said:

Quoted message said:

Do you know any others that I don't have yet? (I'd need a decent
photo of them to include them....)

Quoted message said:

There are the "egg rings" made by Highpath Engineering in Wales. You
can order then in various "egg-ness"es by percentage.

With minimal computation these CW's can be converted into chain speed.
That velocity graph vs. rotation angle would be more interesting and
more revealing of the relative effects. How about it?

Jobst Brandt

<[email hidden]> wrote: With minimal computation these
CW's can be converted into chain speed. That velocity graph vs. rotation
angle would be more interesting and more revealing of the relative effects.
How about it?
^^^^^^^^^^^^^^^^^^^^
The velocity of a bicycle doesn't vary much with each pedal stroke, because
the momentum of the bike/rider carries it through. As a consequence, the
rotational speed of the pedals varies: faster with lower chainring radius.
The Conrad Oho setup provided maximum pedal speed at top-dead-center and
bottom-dead-center. This gets the rider into the "strong" position more
quickly in each stroke. This is most beneficial in hard climbing, so Oho
designed his rings with more out-of-roundness in the granny gear, and less
in the top gear.

Jobst, were you aware of Oho? I have lost track of him, but I always
regarded him as an excellent mechanic/designer.

Quoted message said:

Hi,

Since the Q-Rings folks claim the eccentricity of bio-pace is in the
wrong place, it would be interesting to see where the Q-Rotor "bumps"
are relative (using Rotor's suggested starting holes) to the others
rings, instead of just long-axis vertical.

Joseph

The subject of Q-rings came up on a recumbent bike forum--and the matter
being discussed was that the included instructions are only correct for
a regular upright-style bicycle. When I made the diagram I was more
interested to see how each diverged from its longest axis.

According to Rotor's instructions:, with the right pedal at BDC, the
"short" axis is supposed to be aligned vertical, with the pedal crank.
There's six holes between each crank bolt, and the maximum diversion
suggested is 1 or 2 holes either way, so that's 12 or 24 degrees either
direction.

The O,symmetrics are shown set up the same way (short axis parallel to
the crank) on Julich Cervelo's bike.

The other ones I can't be always certain.
If there's an outer chain pin that's a clue but in at least two of the
best photos I found of SR Ovaltechs and Sugino Cycloids--the photos show
a pair of rings (mid + large) and the larger ring doesn't have a chain
pin at all--(but the larger of each's rings have DECALS, so why would
they put a decal on a mid or inner ring?...). We could assume that with
the right pedal in BDC the decals would be right-side up, but I don't
really know.
~

Leo Lichtman said:

With minimal computation these CW's can be converted into chain
speed. That velocity graph vs. rotation angle would be more
interesting and more revealing of the relative effects.
How about it?
^^^^^^^^^^^^^

Quoted message said:

Quoted message said:

The velocity of a bicycle doesn't vary much with each pedal stroke,
because the momentum of the bike/rider carries it through. As a
consequence, the rotational speed of the pedals varies: faster with
lower chainring radius.

That's why I said "velocity graph vs. rotation angle". That the
shapes vary is obvious and also not visually comparable. That is why
plotting chain movement versus crank angle would give a better
comparison.

Quoted message said:

Quoted message said:

The Conrad Oho setup provided maximum pedal speed at
top-dead-center and bottom-dead-center. This gets the rider into
the "strong" position more quickly in each stroke. This is most
beneficial in hard climbing, so Oho designed his rings with more
out-of-roundness in the granny gear, and less in the top gear.

This whole exercise is ridiculous because the only thing that counts
is aerobic work and that is done primarily with the large muscles of
the leg. What the foot does makes no difference to these muscles as
long as their force and stroke remains at the same rate. The concept
revolves around "fooling" the muscles". and they aren't fooled.
That's why these devices never got anywhere without huge promotional
costs... and then faded away.

Quoted message said:

Quoted message said:

Jobst, were you aware of Oho? I have lost track of him, but I
always regarded him as an excellent mechanic/designer.

I don't recall having heard of him and if he believes in this hocus
pocus, that may be why.

Jobst Brandt

Leo Lichtman said:

I bought a set of elliptical chainrings from their designer (inventer?), a
fellow named Conrad Oho, in Marin County. He and I agreed that the Biopace
rings had their long axis going exactly the WRONG way. In your illustration
comparing the various rings, the long axes are shown aligned in the vertical
direction, without regard to the pedal position. I suggest you redo the
diagram, keeping the pedal axis constant.

Conrad Oho worked for Shimano at the time Biopace was being developed.
According to him, the shape was intended to produce a pedal velocity that
simulated walking or running. He also said that the inventor made big
unsupported logical leaps.

The history of Biopace seems to be that the more it was improved, the
rounder it got.

Yeah, about that time Shoji Onozawa repackaged all the SR-Sakae rings
with tongue-in-cheek as "SR RoundTech"

--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

Quoted message said:

Leo Lichtman said:

With minimal computation these CW's can be converted into chain
speed. That velocity graph vs. rotation angle would be more
interesting and more revealing of the relative effects.
How about it?
^^^^^^^^^^^^^

Quoted message said:

The velocity of a bicycle doesn't vary much with each pedal stroke,
because the momentum of the bike/rider carries it through. As a
consequence, the rotational speed of the pedals varies: faster with
lower chainring radius.

That's why I said "velocity graph vs. rotation angle". That the
shapes vary is obvious and also not visually comparable. That is why
plotting chain movement versus crank angle would give a better
comparison.

I personally think applied force vs rotation angle or knee angle would
be more interesting. But indeed velocity vs rotation tells a lot more
than looking at the outlines of the rings.

Quoted message said:

Quoted message said:

Quoted message said:

The Conrad Oho setup provided maximum pedal speed at
top-dead-center and bottom-dead-center. This gets the rider into
the "strong" position more quickly in each stroke. This is most
beneficial in hard climbing, so Oho designed his rings with more
out-of-roundness in the granny gear, and less in the top gear.

This whole exercise is ridiculous because the only thing that counts
is aerobic work and that is done primarily with the large muscles of
the leg. What the foot does makes no difference to these muscles as
long as their force and stroke remains at the same rate. The concept
revolves around "fooling" the muscles". and they aren't fooled.
That's why these devices never got anywhere without huge promotional
costs... and then faded away.

Sustained power generation is a combination of effective delivery of
(enough) oxygen, and the large muscles ability to efficiently use the
oxygen. I don't think it is ridiculous to suppose that changing how
and when the work done by these large muscles might affect their
efficiency. It may be that the gains (if any) are lost in the noise,
but just because something like Bio-pace doesn't work, doesn't mean
that Q-rings don't. Lada Nivas suck. Lada Nivas are 4 wheel drive.
Jeep Cherokees are 4 wheel drive, therefore they suck too.

That said, my chainrings are round...

Joseph

Quoted message said:

Quoted message said:

Quoted message said:

Jobst, were you aware of Oho? I have lost track of him, but I
always regarded him as an excellent mechanic/designer.

I don't recall having heard of him and if he believes in this hocus
pocus, that may be why.

Jobst Brandt

Ozark Bicycle said:

There was a "road" version in 130mm BCD as early as the mid-eighties.
These might have come under the Biopace HP umbrella, I can't recall
for sure. They were "rounder" than the 110/74mm bcd touring/mtb rings.
I had a set in 52/42 for awhile in ~'86; it was very difficult to
discern the "feel" of those rings from regular round rings.

When I took up cycling in the late 80s I hadn't ridden for years. I
went out and bought a Trek 1400 which unbeknownst to me came with
BioPace 52/42 rings. I never noticed anything weird about the
pedalling stroke.

When I moved from the flatlands of South Jersey to San Diego I knew I
needed help with the hills. I replaced the 42 with a round 39 and
immediately noticed a difference, but that "strange feeling" went away
in a couple of miles. I eventually replaced the BioPace 52 and never
went back. :-)

--
jeverett3<AT>sbcglobal<DOT>net (John V. Everett)

Quoted message said:

This whole exercise is ridiculous because the only thing that counts
is aerobic work and that is done primarily with the large muscles of
the leg. What the foot does makes no difference to these muscles as
long as their force and stroke remains at the same rate. The concept
revolves around "fooling" the muscles". and they aren't fooled.
That's why these devices never got anywhere without huge promotional
costs... and then faded away.

....and then faded back into view? I noticed Bobby Julich was using
some kind of eccentric ring in the Paris - Nice prolog TT.

--
jeverett3<AT>sbcglobal<DOT>net (John V. Everett)

Quoted message said:

DougC said:

Long story short: I decided to try some Rotor Q-rings.

I noticed that some people (on one forum I frequent) kept comparing
Q-rings to the various other non-round chainrings they'd had in the
past, and I got curious as to how different all these different rings
were so I decided to trace a few of them on one image. So far I've
got Rotor Q-Rings, O. Symetrics, Bio-Pace, Sugino Cycloid and SR
Ovaltech.

http://www.norcom2000.com/users/dcimper/assorted/inanities/recumbent/...

Do you know any others that I don't have yet? (I'd need a decent
photo of them to include them....)
~

Hi,

Since the Q-Rings folks claim the eccentricity of bio-pace is in the
wrong place, it would be interesting to see where the Q-Rotor "bumps"
are relative (using Rotor's suggested starting holes) to the others
rings, instead of just long-axis vertical.

The "right" position depends if the oval rings are trying to control
(improve) the torque applied by the cyclists legs, or control the speed of
movement of the cyclists legs in the horizontal and vertical directions.

As I understand it, you get a different design (90 degrees out of phase)
depending which you aim to control. I have compound design rings which get
round this problem on all my bikes :-)

- Nigel (used biopace some time ago on a bike, didn't see what the fuss was
either way).

--
Nigel Cliffe,
Webmaster at http://www.2mm.org.uk/

Whatever the technical arguments, my experience is that Conrad Oho and his friends were definitely right. Giving lower gearing, higher leverage in the "strong", going down position, 90° and 270°, helps get more torque to the wheel. Higher gearing in the weak, top dead center and bottom dead center, 180° and 360°, makes you go through them faster, even without pushing.
And this design, at 90° of the first trend (higher gearing in strongest positions), eliminated the knee problems by being much easier on them.
I have used both the Shimano Biopace on MTBs and Sakae OvalTech on touring bikes for the last 30 years. On my current touring bike, I am much stronger/faster than my friends who are on normal chainrings, especially going uphill.
Just for fun, I have now started using my touring bike (15 kg) instead of my racing bike (8 kg) when they are all on their racing bikes on Sunday mornings. And I beat them more regularly than when riding my racing bike.
The more people are convinced ovals don't work, and the more people I will beat more comfortably. So, don't change a thing for me. And thank you Conrad, Shimano, Sakae, Sugino...