Vuelve el Biopace?

Visteis ayer la contrarreloj masculina del Campeonato del Mundo.
Vinokourov llevaba un plato estilo Biopace(aquellos platos ovalados con los que Shimano pretendió eliminar el punto muerto,allá por los principios de los '90),pero mucho más ovalado que aquellos.
El año pasado en Hamilton(Canadá) creo que también lo llevaba.
Estoy buscando fotos,pero no encuentro ninguna en la que se vea,si algún alma caritativa encuentra,que la cuelgue.

 

este tb lo utiliza Boby Jullich en Bicicleta Vasca


Olympic Tech: Bobby J and his funky chainrings
By Andrew Juskaitis
VeloNews Technical Editor
This report filed August 18, 2004

Click image to enlarge




When Bobby Julich crossed the finish line just 26.45 seconds behind teammate Tyler Hamilton in Wednesday's Olympic individual time trial, it wasn't just a victory for a man and his country-technology also won in the streets of Athens.

Helping to power Julich's bike were two very unusual chainrings that could very well transform the way we propel our bicycles in the future. Julich was riding a pair of French made, out-of-round, "Osymetric" chainrings which Julich claims have helped him all season.

Now before you say, "Biopace," think again. In a phone interview with VeloNews from France designer Jean-Louis Talo was clear to point out that his patented out-of-round chainrings are considerably different that Shimano's original Biopace and Biopace II chainrings.

"Biopace did very little to address the dead-spot in a rider's pedaling stroke," Talo asserted. "My chainrings are designed to optimize the power portion of the stroke while minimizing the dead-spot. If you look closely, you can see my chainrings aren't just oval or elliptical as others have been, but shaped entirely to take advantage of a rider's leg musculature. The geometry we use is two successive curves having a unique symmetry, both with a central point of rotation. When the pedal is up [at 90 degrees] a rider's strength is minimal so the ring radius is small as well. When the pedal comes near to horizontal, the rider's strength is more, so the chainring is bigger to take advantage of that. Unlike Biopace, my rings constantly change radius to take full advantage of the complete power stroke of a rider. This is the first time this has been accomplished in a chainring."


Click image to enlarge
by AFP


Today in Athens


Talo pointed to some of the impressive data that he claims was obtained from independent testing carried out in Europe. He reports improvements of between 5- and 15-percent gains in efficiency which can result in a 3-percent gain in speed (given identical input effort). Talo also claims his chainrings can help alleviate chronic knee stress issues by providing more mechanical advantage when a rider's knee is bent at 90 degrees (one of the most stress-prone positions of a rider's power stroke).

This isn't the first time Julich has raced the Osymetric chainrings. It was almost one year ago that we saw these strange looking rings on Julich's bike in Hamilton, Ontario Canada during the 2003 World Road Championships. There he claimed that the rings, "we good for 5 seconds per kilometer."

Julich used the unusual rings at the Vuelta a Pais Vasco this year, where he beat Hamilton (Phonak) by less than one second in a time trial at the Spanish stage race. Julich also raced the technology in the climbing stages of this year's Tour de France, although he chose to run only the inner ring to satisfy his Shimano sponsorship.

The Osymetric rings are not brand new to the cycling world. In fact, Talo has been testing variations of his rings with professional teams, including the old Festina team, as well as individual riders - Jens Voigt, Alexander Vinokourov and Julich - since late 2000. Talo reports that riders favor the rings for climbing, and also feel they're an advantage in heavy-power flat stages (i.e. TT). The chainrings aren't' yet available here in the United States, but should soon be available through a major distributor (by Interbike Talo commented.)

If Julich's Athens success is any evidence of the rings' advantages look for resurgence of interest in out-of-round rings in the near future. One of us at VeloNews will be among the first North Americans to obtain the rings, so stay tuned for a report in an upcoming issue.

 

Paso, donde se ponga un Rotor, que además es español...

 

joooder que recuerdos!!!

Mi primera bici (una spz rockhopper del 90) los llevaba. Creo que no eran shimano, sino sountur, o algo asi....

Que bueno!!!!jajajaj

 

Mi Albero de los 90 equipaba unos Biopace de Shimano.
Ha llovido mucho desde entonces......

 

Esto es una chuninada como un templo ¡Rotor Al Ataquerrrr!

Saludos CordialeS!

Pd.: Terminaremos sacando la bici de platos ovales y el manillar de carretera a lo "John Tomac"?

 

Yo tuve hace cosa de 12 años lo menos unos shimano biopace 300 xl, y la verdad a mí me parecía una cosa muy rara y yo no notaba nada diferente a unos platos normales.
Creo q se queda todo en algo estético, pero a mi me parecen muy feos, y dudo mucho su utilidad.

 

Si, shimano abandono ese sistema hace años será por algo, encuentro ridiculo que lo vuelvan a usar, incluso a nivel estético, es horroroso y para ajustar el desviador no digamos. Yo desde luego no lo montaría en mi bici, aunque gane 3 segundos por km.


Saludos

 

Y ya lo dice claramente el creador,no es Biopace.
No lo veo nada práctico,sobre todo en montaña,porque la cadena sufre cambios constantes de tensión,ya se veía en la tele que el cambio se movía bastante,o sea,que en montaña,con los baches y demás,tiene que dar muchos quebraderos de cabeza.
Muy bueno Carbon.

 

msxtr,

eso en una crono es un monton

 

Ya, pero yo no soy pro, o sea que me da igual, jejeje.



Saludos