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Biopace triple crankset, a non-round crankset

Biopace is a tradename for a type of ovoid bicycle chain ring manufactured by Shimano from 1983 to 1993^[1]^[2] The design was intended to help overcome the "dead zone" where the crank arms are vertical and riders have little mechanical advantage.^[3]

Biopace chainrings have a reduced chainring diameter coinciding with the cranks being horizontal. This is supposed to smooth the pedaling action, allowing the rider's feet to carry more momentum through the power stroke, and having it smoothly removed at the bottom of the stroke rather than encouraging riders to push bigger gears and risk knee damage due to higher knee joint loadings.^[3]^[4]

This is different from the design of other oval style chainrings, which have the smaller effective chainring diameter coincide with the cranks being at the top dead center (TDC) and bottom dead center (BDC), thus making the crank easier for the rider to turn through bottom dead center for constant chain tension. By having the chainring at its peak effective diameter with the cranks level, where the rider has maximum leverage over the crank during the power stroke, these designs are supposed to make better use of the rider's power output.^[3]

Some cyclists find the benefits of Biopace worthwhile, including well-respected bike mechanic Sheldon Brown.^[3] Some riders may also value a Biopace crankset for its historical accuracy on a vintage bike, for its novelty value, or even retro-cachet.

References

^ Berto, Frank J.; Ron Shepherd; et al. (2005) [2000]. The Dancing Chain: History and Development of the Derailleur Bicycle (2nd ? ed.). San Francisco, CA, USA: Van der Plas Publications/Cycle Publications. p. 297. ISBN 1-892495-41-4.
^ Berto, Frank J. (2016) [2000]. The Dancing Chain: History and Development of the Derailleur Bicycle (5th ed.). Cycle Publishing/Van der Plas Publications. ISBN 978-1-892495-77-8. Retrieved May 30, 2017.
^ ^a ^b ^c ^d "Sheldon Brown: Biopace". Retrieved 2011-08-10.
^ "Rotor Bike Components: QRINGS GENERAL INFORMATION" (PDF). Archived from the original (PDF) on 2011-09-02. Retrieved 2011-08-10.

[Berto-1] Berto, Frank J.; Ron Shepherd; et al. (2005) [2000]. The Dancing Chain: History and Development of the Derailleur Bicycle (2nd ? ed.). San Francisco, CA, USA: Van der Plas Publications/Cycle Publications. p. 297. ISBN 1-892495-41-4.

[2] Berto, Frank J. (2016) [2000]. The Dancing Chain: History and Development of the Derailleur Bicycle (5th ed.). Cycle Publishing/Van der Plas Publications. ISBN 978-1-892495-77-8. Retrieved May 30, 2017.

[Brown-3] "Sheldon Brown: Biopace". Retrieved 2011-08-10.

[4] "Rotor Bike Components: QRINGS GENERAL INFORMATION" (PDF). Archived from the original (PDF) on 2011-09-02. Retrieved 2011-08-10.

[1]

[2]

[3]

[4]

@@ Line 1: / Line 1: @@
-[[Image:Biopacemtb.jpg|thumb|right|Biopace crankset]]
+[[File:Biopacemtb.jpg|thumb|right|Biopace triple crankset, a non-round crankset]]
-[[Image:Biopacesticker.jpg|thumb|right|The Biopace logo on a chainring]]
+[[File:Biopacesticker.jpg|thumb|right|The Biopace logo on a chainring]]
-'''Biopace''' is a [[tradename]] of a type of [[ovoid]] [[bicycle]] [[Crankset#Chainrings|chain ring]] manufactured by [[Shimano]] from 1983 to 1993<ref name=Berto>{{cite book
+'''Biopace''' is a [[tradename]] for a type of [[Crankset#Non-round_chainrings|ovoid bicycle chain ring]] manufactured by [[Shimano]] from 1983 to 1993<ref name=Berto>{{cite book
-  | last =  Berto
+  | author=Berto, Frank J.
-  | first = Frank
+  | authorlink =
-  | authorlink =
+  | author2=Ron Shepherd
+  | display-authors=etal
-  | coauthors = Ron Shepherd, et al.
-  | title = The dancing chain : history and development of the derailleur bicycle
+  | title= The Dancing Chain: History and  Development of the Derailleur Bicycle
   | publisher = Van der Plas Publications/Cycle Publications
   | date = 2005
+  | origyear=2000
+  | edition=2nd ?
   | location = San Francisco, CA, USA
   | pages = 297
   | url = http://www.cyclepublishing.com/cyclingbooks/dc.html
+  | isbn = 1-892495-41-4
-  | isbn = 1892495414}}</ref> The design was intended to help overcome the "dead zone" where the [[Crankset|crank arms]] are vertical and riders have little [[mechanical advantage]]. <ref name = "Brown">{{cite web
+}}
+</ref><ref>
+{{cite book
+ |author=Berto, Frank J.
+ |title=The Dancing Chain: History and  Development of the Derailleur Bicycle
+ |edition=5th
+ |year=2016
+ |origyear=2000
+ |publisher=Cycle Publishing/Van der Plas Publications
+ |ISBN=978-1-892495-77-8
+ |url=http://www.cyclepublishing.com/cyclingbooks/
+ |accessdate=May 30, 2017
+}}</ref> The design was intended to help overcome the "dead zone" where the [[Crankset|crank arms]] are vertical and riders have little [[mechanical advantage]].<ref name = "Brown">{{cite web
 | url = http://sheldonbrown.com/biopace.html
 | title = Sheldon Brown: Biopace
 | accessdate = 2011-08-10}}</ref>
-The intention of most oval style chainrings is that at top and bottom dead centre (TDC and BDC) the effective diameter of the chainring is small, thus making the crank easier for the rider to turn through BDC for a constant chain tension. By having the chainring at its peak effective diameter with the cranks level, that is, where the rider has maximum leverage over the crank during the power stroke, better use can be made of the rider's power output.<ref name = "Brown" />
+Biopace chainrings have a reduced chainring diameter coinciding with the cranks being horizontal. This is supposed to smooth the pedaling action, allowing the rider's feet to carry more momentum through the power stroke, and having it smoothly removed at the bottom of the stroke rather than encouraging riders to push bigger gears and risk knee damage due to higher knee joint loadings.<ref name = "Brown" /><ref>{{cite web
-Biopace chainrings do almost exactly the opposite to this, having the reduced chainring diameter coinciding with the cranks being horizontal. The reason this is beneficial is that it tends to smooth the pedalling action, allowing the rider's feet to carry a lot of momentum through the power stroke, having it smoothly removed at the bottom of the stroke rather than encouraging riders to push bigger gears and risk knee damage due to higher knee joint loadings.<ref name = "Brown" /><ref>{{cite web
 | url = http://www.rotorbikeusa.com/pdf/More%20information_Q%20Rings.pdf
 | title = Rotor Bike Components: QRINGS GENERAL INFORMATION
-| accessdate = 2011-08-10}}</ref>
+| accessdate = 2011-08-10
+| archive-url = https://web.archive.org/web/20110902151119/http://www.rotorbikeusa.com/pdf/More%20information_Q%20Rings.pdf
+| archive-date = 2011-09-02
+| url-status = dead
+}}</ref>
+This is different from the design of other oval style chainrings, which have the smaller effective chainring diameter coincide with the cranks being at the top dead center (TDC) and bottom dead center (BDC), thus making the crank easier for the rider to turn through bottom dead center for constant chain tension. By having the chainring at its peak effective diameter with the cranks level, where the rider has maximum leverage over the crank during the power stroke, these designs are supposed to make better use of the rider's power output.<ref name = "Brown" />
-Biopace chainrings have been cited as the epitome of a solution looking for a problem among the biking press, though there is little evidence to suggest they were particularly bad, just unnecessary.{{Fact|date=January 2009}} However some independent-minded bikers find their benefits worthwhile, including well respected bike mechanic [[Sheldon Brown]]. Some riders may also value a Biopace crankset for its historical accuracy on a vintage bike, for its novelty value, or even retro-cachet. Increased mechanical complexity of using these chainrings with a [[Derailleur gears|front derailleur]] is one possible disadvantage.
+Some cyclists find the benefits of Biopace worthwhile, including well-respected bike mechanic [[Sheldon Brown (bicycle mechanic)|Sheldon Brown]].<ref name = "Brown"/> Some riders may also value a Biopace crankset for its historical accuracy on a vintage bike, for its novelty value, or even retro-cachet.
 == See also ==
 * [[Crankset]]
+* [[Osymetric]]
 ==References==
 {{reflist}}
-[[Category:Bicycle parts]]
+[[Category:Bicycle drivetrains]]
-[[ca:Biopace]]
-[[es:Punto muerto (bicicleta)]]
-[[nl:Biopace]]
-[[pl:BioPace]]
-[[de:Biopace]]