Conference noted::bicycle

    Don't know if this is the trend or not.
    
    However, when my SO was trying to buy a new crank in August, it
    seemed like 90% of the available cranks were Biopace.  Very limited
    selection for a person who wanted round chainrings.
    
    	-Nancy

    Re: Round vs. Square rings,
    
    	Colorado Cyclist has Biopace rings in 42, 52 and 53 tooth
    sizes for sale at $5.99 each.  These are *new Shimano* rings
    that were selling for up to $40.00 each at the height of the
    square ring craze, just a few months ago.  It's obvious to me
    that Shimano has or will soon abandon biopace on their road
    machines but the jury might still be out with the rough riders
    (ATB's) since they favor lower cadence high torque applications
    such as hill climbing.
    
    						_Jerry
    

    As usual, I'm behind the pace and confused to boot!  
    
    My old chainring was round.  My new triple chainring on my Trek is
    biopace and I love it.  I don't have any good technical explanation why
    I love it, but I do.  I usually spin around 80-90 rpm, and use pretty
    low gears, averaging 13-17 mph...
    
    re -.1
    
>    that were selling for up to $40.00 each at the height of the
>    square ring craze, just a few months ago.  It's obvious to me
>    that Shimano has or will soon abandon biopace on their road
>    machines but the jury might still be out with the rough riders
    
    So, why is this a craze?  Why is it fading?  What is good or bad about
    biopace and why would Shimano abandon them on their road bikes?
    
    Dave P.

    Dave,  there seem to be two factions regarding Biopace (those who
    love it and those who don't) - as an overgeneralization, Biopace
    *seems* to be preferred by non-racers, those who do other activities
    involving their legs (especially running, walking) (since Biopace
    more closely models non-"cyclic" i.e., pumping leg-action), or those
    newer to biking (because these people, athletically fit or not, are
    more accustomed to "pumping" use of their legs).  Circular rings
    seem to be preferred by racers (to whom smooth, uniform, rapid
    cadence is important) and bicycle obsessives (speaking for myself)
    who do a lot of biking, and less of other activities.
    
    ...but I emphasize: these are my impressions!  Not scientific.
    
    Nancy,  I'm sure there's a good supply of round chainrings from
    certain Italian manufacturers - what did your SO eventually wind up
    with?  I agree, Biopace seems ubiquitous elsewhere.
    
    -john

    PS: Mountain biking also seems to favor the Biopace approach.
    (When I said racers, I meant road-racers.)  If you've watched
    a mountain bike event, and seen the terrain these guys are
    expected to go over, you'll see why!
    
    -john

    <<< Note 1330.4 by SHALOT::ELLIS "John Lee Ellis - assembly required" >>>

                             -< why/when Biopace >-
Dave,

And then there's those guys, like me, who are bicycle obsessive, racer types, 
who sprint well, time trial well, do mega-mileage (tho John does 
mega-mega-mileage) who absolutely LOVE Biopace.

I think the problem is that a lot of long-time cyclists just think round is 
better, but haven't given Biopace a chance.  It does feel a lot different when 
you first try them, and like anything else, takes time to get accustomed to.  
If a pro racer ever used them and was successful, you wouldn't hear all the 
negative stuff.  Just look at what Greg Lemond did for aero bars!

Unfortunately, Shimano either hasn't done the research to provide the reasons 
that Biopace is better, or at least equal to round rings, or they did, and 
they didn't like the results.  They did some research a long time ago, but it 
was aimed at recreational or touring riders.

Of course, I haven't given round rings a try... maybe I'd be faster on them?  
I am thinking about trying them out this winter, but only because I can't get 
Biopace in a wide enough variety of sizes.  They only make the racing rings in 
42, 52 and 53, and I'd like to get a 39, maybe a 40.

It will be interesting to see if I become a round ring convert...

Kevin

    Re .4
        
    > Nancy,  I'm sure there's a good supply of round chainrings from
    > certain Italian manufacturers - what did your SO eventually wind up
    > with?  I agree, Biopace seems ubiquitous elsewhere.
    
    
    He used the "I _NEED_ round chain rings" excuse to buy himself a
    nice Campy Nuovo Record crank that Pedal Power has had sitting around
    in a box for a number of years now.  PP even sold it to us at the
    price they paid for it, not the price they have to replace it at.
    
    	-N

I have both, round on the BASSO and Bio on the Centurion. I use the Centurion
to pull a trailer and when I ride slow. This is were the Bio-pace works well.
When pedalling at a low rpm you notice the dead spots in the top and bottom of
the stroke, with the Bio-pace the distance of getting through this dead spot is
shorter. Does this make climbing a hill easier? Well, what its supposed to do
is allow you to spend more time in the power stroke and less time in the dead
spots. Then the wasted energy, lost in these spots can be put into the power
stroke.  Now if your spinning your cranks you're getting through these dead
spots fast enough or if you are really a good at spinning there are no dead
spots in your stroke. So no need for something to omit what isn't there. Thats
why the pro's don't use them.

Tom

     Although I have no personal experience with Bio's, I have read up on
    the topic. They were designed to do exactly what was stated about in-
    creasing torque efficiency (hills especially). I also read that the
    degree of the elipse was decreased this year due to new experimental
    findings. 
    
     IMHO, pro's are probably staying away from them because it has taken
    them many years and miles to develop their technique and to introduce
    such a radical change would certainly put them years behind.
    
     Again, I have to qualify, I haven't even tried them. I only know what
    I have read.
    
      Chip

           <<< Note 1330.8 by MCIS2::DELORIEA "Common sense isn't" >>>
                          -< Bio-Pace has its place >-

>When pedalling at a low rpm you notice the dead spots in the top and bottom of
>the stroke, with the Bio-pace the distance of getting through this dead spot is
>shorter. Does this make climbing a hill easier? Well, what its supposed to do

This dead spot will always be there, IMO, to some degree, depending upon 
cadence and technique.  I don't believe its really possible to eliminate it 
thru technique.  Minimize maybe, eliminate, no.  The pros are just much better 
than the rest of us at minimizing it.

I bet that if a pro-quality cyclist trained on appropriately designed 
elliptical chainrings his entire career (like they do on round rings) that he'd 
be at least as good, if not better.

I've spent MY whole career on Biopace, and can spin quite well.  And climb 
quite well.  That's enough proof for me.

Kevin

I recently bought a Trek 1400 and it came with Biopace.  I had previously been 
riding with round chain rings and tend to spin around 100-110.  I honestly can't
tell any difference between round and Biopace.  I figured that since I spin fast
(maybe too fast?) that the Biopace would rapidly find it's way to may spare 
parts bin.  

Mark

    I can't say that I ride fast or that I climb hills fast since all
    such things are relative.  I'm faster than some, slower than many.
    I'm glad to hear someone else say that he cannot feel the difference.
    I sometimes feel that I'm somewhat of a clod.  I have biopace on
    one bike, I have done many miles on that bike this year but I have
    often ridden other bikes for various reasons.  I do not see how
    those off-round rings make much of a difference.
    
    Sometimes I felt like it was "the emperor's new clothes" but I don't
    thinks it's any difference from having an aero seatpost.
    
    I broke two spokes yesterday (one front, one left rear), now, you otta
    see a bike go faster when you start removing spokes, you really do!!!
    :-)  I'll probably fly if I remove a dozen more. =^)
    
    ed

>            <<< Note 1330.8 by MCIS2::DELORIEA "Common sense isn't" >>>
> 
> When pedalling at a low rpm you notice the dead spots in the top and bottom of
> the stroke, with the Bio-pace the distance of getting through this dead spot is
> shorter. 
    
    Looking at how Shimano position Biopace rings relative to the crank,
    the dead spot should be longer since the long axis of Biopace is more
    or less in line with the crank arms. Assuming that the dead spot occurs
    when the cranks are near vertical, this means that the chainwheel is
    rotating at its slowest through the dead spot - ergo, the dead spot is
    longer. Conversely the short axis lies on the power stroke, so the
    Biopace ring is effectively presenting a lower gear than the round
    equivalent. Maybe this is why Biopace is a sales success - it tricks
    new cyclists into using a lower gear! Not a bad idea, since beginners
    to cycling have to be educated into spinning rather than grinding
    along in impossibly high gears.
    
    It's interesting to me to note that Biopace rings are squarish rather
    than elliptical. I'd always assumed that this proved they must have
    done some research on the subject, else why choose the funny shape?
    
    Elliptical rings have appeared in the past, and here in the UK there's
    a small firm that specialises in making them, to fit any chainset. But
    when they've been used previously the concept was to align the long
    axis to the power stroke. That really would hurry the chainwheel
    through the dead spot. I've seen mention recently of people rotating
    Biopace one notch to emulate this, and claiming an improvement - anyone
    tried doing that?
    
    I use round chainrings myself, and don't see any need to change. I was
    on an ATB with Biopace, and it felt lumpy at first. After I'd fallen
    off a few times, I was too lumpy myself to care.
    
    
    Rod

    My opinion is that eventually your muscles will adapt to either style,
    but you still have to do the same amount of work.  There are three
    ameliorating factors:
    
    o If your muscles are used to the profile that Bio-Pace gives (runner), 
      then you can get fast on a bike faster.  
    
    o Biopace's off-round shape can lead to shifting problems under extreme
      conditions (racing).
    
    o Biopace sure feels nice in out-of-the-saddle climbs.
    
    
    MATT

	About two years ago I wanted to improve my hill climbing 
    ability so I went out and bought bio-pace for my C-dale.  Since
    the cranks I had on my bike used a campy bolt pattern the only
    way to accomplish this was to buy an entire crank assembly with
    square rings, which I did (Shimano 600).  Since I still had round
    rings on my other bikes, it was annoying going back and forth 
    since I found a distinct difference between the two, probably
    because I spend more time on the samller (42T) ring than a lot
    of other riders and the smaller the ring the more distinct the
    feeling.  After about a year I converted just the outer ring
    to round.  While this may work for ATB riders who spend most
    of their time on the two small rings and save the big round
    ring just for the road, it's very annoying when the shift
    patterns on your road bike require switching back and forth
    from the small and large ring.  I just couldn't get used to
    it so I saved the lower five gears just for hills and the upper
    5 just for average grade roads until I broke down and purchased
    a small round ring.  The bottom line is it cost me two years,
    a crank set a new large round ring (old one was Campy bolt pattern) 
    and a new small ring and untold hours of adjustment, discomfort
    and disappointment, to get back to where I was two years ago.
    
    	I think that Digital as a company could learn a lot from
    Shimano on how to *market* new technology.
    
    					_Jerry

    Anyone see B.C. in todays comics?
     Looks like the first example of Bio-pace.
    
    Joe
    
    
    
    

       	A couple of months ago I purchased a replacement for my Shimano
    	26-tooth Bio-Pace Chainring.  This one was dubbed HP (High Per-
    	formance).  There may have been a II in there somewhere, but I
    	can't remember at the moment.  Anyway, it's significantly less
    	elliptical then my original one.  I don't know if Shimano is
    	making different "models" of Bio-Pace chainrings now, or this
    	HP-type is the "one and only/new and improved" model.  I did
    	find that I'm not "breaking traction" as much as I did with my
    	previous ring.  Perhaps that's due to the decreased torque
    	available with the less extreme ellipse.
    
    								  Mike