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Conference noted::bicycle

Title: Bicycling
Notice:Bicycling for Fun
Moderator:JAMIN::WASSER
Created:Mon Apr 14 1986
Last Modified:Fri Jun 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:3214
Total number of notes:31946

1980.0. "Shimano Biopace chainrings..." by CGOA01::OWONG (SKIWI in Canada (VAO)) Fri Jun 28 1991 00:59

    Can someone tell me what ratios Shimano Biopace mountain bike
    chainrings come in?  I phoned the local shop here and they said the
    only sizes are 38 and 44.  I interested in a 40 to minimise any
    duplication of ratios with a 14-30.  Prices in the US would also be
    appreciated.
    
    	Owen
T.RTitleUserPersonal
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1980.1try round rings?OXNARD::KLEEKen LeeFri Jun 28 1991 15:296
    Biopace is loosing popularity around here.  Few new bikes carry them
    and replacement parts are getting hard to find.  Apparently, Biopace
    was a temporary fad with little or no benefit.
    
    Ken
    
1980.2Mine are 48/38/28ASG3::STEWARTI hear and obey the voice of Landru.Mon Jul 01 1991 15:4512
My mountain bike came with 48/38/28, and are the Exage 300LX components for the
chainrings.  My bike is a Nishiki Manitoba.

I'm planning on some day replacing the 48 biopace with at least a 48 circular,
but I'm debating on going to a 52 circular.  Too bad that Rock Rings don't 
come in that large of a size.

Later,

Andy

1980.3Should be a lot of sizes if you look aroundNCADC1::PEREZJust one of the 3 remaining samurai!Tue Jul 09 1991 00:267
    I've seen Biopace rings in 26,28, 36, 38, 44,48, and 50 tooth.  Perhaps
    Nashbar or Performance have others.  
    
    BTW:  I don't know where "around here" is, but here in Minneapolis
    there are a wide selection of Biopace rings in the bike shops and I see
    a lot of new bikes from Nishiki, Trek, and my Cannondale with Biopace
    rings.  To each his own...
1980.4mixYNGSTR::BROWNTue Jul 09 1991 14:233
    I ride a 42 inner biopace ring for mountains and a 53 outer round ring
    for cadence.  According to the folks at Bicycle Alley, this mix is a
    pretty common setup.  -kb
1980.5Orientation of Biopace ringsVMSSPT::PAGLIARULOThu Aug 10 1995 09:0620
	What should be the orientation of the Biopace rings in relation to the 
crank?  I pulled everyting apart for cleaning and now can't remember which way
the elipse goes:

like this||      or like this  
        -||-		      ----
       | || |                |    |
       | || |                |    |
       | () |              ====()====
       | || |                |    |
       | || |                |    |
       | || |                 ----
        -||-
         ||

I called a bike shop and one said it didn't matter and the other didn't know.

Thanks,

George
1980.6PCBUOA::KRATZThu Aug 10 1995 12:456
    If the large ring has the small "knob" (that little protrusion to
    help the chain from jamming/dumping), I think that should line up
    under the crank.  The small ring's markings should then line up with
    the large ring.  k
    
    
1980.7EXPERI::MENTALSingletrack MindThu Aug 10 1995 14:169
>	What should be the orientation of the Biopace rings in relation to the 
>crank?  

As far away as possible 8^) (sorry, couldn't resist).

/ken


1980.8RANGER::WASSERJohn A. WasserFri Aug 11 1995 16:529
> What should be the orientation of the Biopace rings in relation to the crank?

	The downstroke of the pedal is where you can generate the most
	power so the oval should be about vertical when the crank arm
	is in the first quadrant.  

	Start with the chainring-side pedal at the top and the longest 
	dimension of the oval vertical.  Then rotate the cranks clockwise 
	until the two sets of mounting holes line up.