Shimano Biopace Chainrings?
DrKnow
These non-round rings came on the market in the mid-eighties as the
greatest energy-efficiency bike invention since chain drive, yet five
years later they were all but gone. Why?
[If you must know, I have had them on a touring triple since 1986, and I
think they work fine, especially on the granny gear--a 28 in my setup. So
I'm really perplexed why they went away so fast.]
--
"Stay low and always present a moving target to the enemy."
My old Drill Sergeant
Folsomjack
An unfounded rumor was started that they were knee killers and the histeria
started. The work and work well and do not damage the knees.They do cause the
rear derailer to move back and forth as chainslack is taken up each revolution
but they match the probable power potential of an average rider better than
rounds Folso...@aol.com
Matt Castelein
In addition to this, clipless pedals made it possible to apply
force to the crank in any direction, making biopace somewhat
pointless.
--
Purgamentum init, exit purgamentum.
- Matt Castelein - System Operator -
-=Cold Fusion Online, Rochester NY=-
Web- http://www2.rpa.net/~night1/sysop.html
Patrick Sheridan
> I'm really perplexed why they went away so fast.]
>
> --
> "Stay low and always present a moving target to the enemy."
> My old Drill Sergeant
giving you the feeling of pedaling in a "circular" motion. For the
average cyclist this is not a problem but for more advanced riders who
don't only put a down-force on the pedal but guide it all the way round
it is hard to follow that motion. Results are that you spend all your
power on the down stroke and almost none on the remainig movement.
Walter Knapp
Patrick Sheridan wrote:
> The problem is that they emphasize the up and down motion rather than
> giving you the feeling of pedaling in a "circular" motion. For the
> average cyclist this is not a problem but for more advanced riders who
> don't only put a down-force on the pedal but guide it all the way round
> it is hard to follow that motion. Results are that you spend all your
> power on the down stroke and almost none on the remainig movement.
I still have biopace on my mtb. It takes a little getting used to, but
you can do a full circle spin on them. I don't guide the pedal around, I
apply power around the circle.
Tim
I got both (clipless pedals & bio-pace rings) at the same time...and I
don't know what caused the problem but I developed knee pain that was so
bad I couldn't hardly push the clutch in on my car after a 50/60 mile
ride. I got rid of the biopace on a well respected, cycling specific,
Orthopedic doctor's recomendation. I haven't had that kind of pain in my
knee again. That was many thousands of miles ago and I'm on my third or
fourth set of clipless pedals. That ain't no rumor! Regards, Tim Long
DrKnow
In article <34D5D5F7...@agrar.uni-giessen.de>, Patrick Sheridan
<Patrick....@agrar.uni-giessen.de> wrote:
> The problem is that they emphasize the up and down motion rather than
> giving you the feeling of pedaling in a "circular" motion. For the
> average cyclist this is not a problem but for more advanced riders who
> don't only put a down-force on the pedal but guide it all the way round
> it is hard to follow that motion. Results are that you spend all your
> power on the down stroke and almost none on the remainig movement.
I guess I can see the point of this one a bit, although the effect is
quite subtle in the big rings. I ride round rings on my race geometry
bike and don't really notice a difference there. But when I'm up out of
the saddle for a long climb in the inner triple 28 ring, I really think
the Biopace shape helps get the most out of the portion of the down stroke
when all my weight is on a single crank arm. I guess this would be
between about 45 and 160 degrees past top center.
From an engineering perspective, I wouldn't just assume that a perfectly
circular motion is bio-mechanically most efficient, anyway. Human beings
aren't steam engines, with pistons and connecting rods. When you really
think about it, the only thing evolution prepares us for is to RUN...all
this other stuff--biking, skating, skiing--is sort of unnatural.
Then again, maybe it was all marketing hype, like so many other bike
fads..... Incidentally, I've had no knee troubles of any kind, and I
would estimate about 10K miles on the Bio's. And I don't run!
Thanks for the responses,
Doug
--
Doug Knowles
"Stay low and always present a moving target to the enemy."
My old Drill Sergeant
If you want to reply, send to drkn...@dnai.com
James Connell
They went away because Shimano invented a New type of chain ring.
They called it *Round Tech*. It was the latest thing in power and
efficiency.
Can you believe it? A new type of chain ring and it's ROUND!
In a more serious line, most of us found the biopace rings didn't
do much good and hurt our ability to *spin* smoothly. I know of a
few people who still use them and one guy who won't use anything
else (he also thinks 7075 Al is stronger than steel though). the
basic idea behind Biopace (as i remember it) was to match the
biomechanics of the leg, kind of like the cams on some weight
machines. A number of exercise pysiologists pointed out that the
rings would have to be matched to the individual to be effective,
which might explain why some people liked them and others thought
they were awful.
--
James Connell
Do not Fold, Spindle, or Mutilate.
Opinions expessed herein do not necessarily reflect those of the
author.
the usual with the address.
DrKnow <drknosp...@dnospamai.com> wrote in article
<drknospammers97-...@dnai-207-181-206-97.dialup.dnai.co
m>...
> These non-round rings came on the market in the mid-eighties as
the
> greatest energy-efficiency bike invention since chain drive, yet
five
> years later they were all but gone. Why?
>
> [If you must know, I have had them on a touring triple since
1986, and I
> think they work fine, especially on the granny gear--a 28 in my
setup. So
> I'm really perplexed why they went away so fast.]
>
> --
Garry Lee
All this round pedalling stuff is bunk. The power comes from the down
stroke. The round pedalling stuff is a combination of wishful thinking and
the ethereal.
Biopace rings are not harmful. I rode them, and round rings, for years. I
did exactly the same speeds in time trials. They don't cause knee problems
either.
That's like saying, I cycled on Tuesday and got a severe knee pain. I
never cycled on Tuesday again and got no pain, therefore Tuesday causes
pain. THe knee pain could have been due to SPD misalignment etc. etc.
Michael Sweigart
Garry Lee wrote:
>
> All this round pedalling stuff is bunk. The power comes from the down
> stroke. The round pedalling stuff is a combination of wishful thinking and
> the ethereal.
> Biopace rings are not harmful. I rode them, and round rings, for years. I
> did exactly the same speeds in time trials. They don't cause knee problems
> either.
That is like saying I smoked cigarettes for 50 years and did not get
cancer so therefore from my one example we can conclude that smoking
does not cause cancer.
> That's like saying, I cycled on Tuesday and got a severe knee pain. I
> never cycled on Tuesday again and got no pain, therefore Tuesday causes
> pain. THe knee pain could have been due to SPD misalignment etc. etc.
The knee pain also could have been from the rings- you cannot disprove
or prove it since there was no major study on it. I have just converted
my road bike from bio pace. I had a problem with one of my knees during
the bio pace and after the bio pace. I think it was from that big
non-circular rock I hit on my MTB :)
CJ
DrKnow wrote :
> These non-round rings came on the market in the mid-eighties as the
> greatest energy-efficiency bike invention since chain drive, yet five
> years later they were all but gone. Why?
>
> [If you must know, I have had them on a touring triple since 1986, and I
> think they work fine, especially on the granny gear--a 28 in my setup.
So
> I'm really perplexed why they went away so fast.]
>
Biopace disappeared because they didn't feel "natural" to a lot of folks.
In a test done by MBA in 1986 (way back before it became Zap-crap), all the
tested cyclists posted better times with biopace, and all the cyclists
hated the feel.
The design was intended to slow down the pedal stroke at the top of the
crank rotation so that the bio-mechanics of opening/closing the knee (ie,
the duel tween the quads and the hamstrings) are facilitated.
I've used them for many years...because I have a really bad knee (4
operations). I've never had any problem with them, but with a regular round
granny, my knee joint burns and swells up.
The mail order place called Loose Screws still had them for sale last year.
--
Email address is bogus - please reply to newsgroup only.
Larry Leveen
SHeldon Brown has a great article on Biopace on his web page (a link is on
my page). It debinks myths and as usual, is a great lesson.
I have several Biopace rings for sale ($4 each) -- see my web page.
--
Larry Leveen
Velorution! The Bicycle "Freeware" Infopage
http://www.olywa.net/leveen/homepage.html