Julich's climbing/TT chainring... What's up with that?

Jul 25, 04 1:17

Post #1 of 15 (2154 views)

I just watched Frankie Andreu's piece on Bobby Julich's special chainring. From what I gathered, the size of the teeth varies depending on the position in the pedal stroke, emphasizing power in some areas and I'm not sure what in the others. (Sort of biopace-esque)

Can anyone explain this? Also, if these rings do actually work, what are the odds that they'll be banned by the UCI before next year rolls around?

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Re: Julich's climbing/TT chainring... What's up with that? [Khai] [ In reply to ]

Jul 25, 04 5:40

Post #2 of 15 (2088 views)

My understanding is that it lengthens the downstroke where you are pushing/stomping.

"your horse is too high" - tigerchik

Re: Julich's climbing/TT chainring... What's up with that? [Khai] [ In reply to ]

Jul 25, 04 5:46

Post #3 of 15 (2084 views)

they have been around for years, and they are UCI legal

note that the UCI does not ban every new item that the peloton uses, case in point - Rotor Cranks have been used in the Vuelta for the past two years, and will be there in force again this year on the TT stages

Re: Julich's climbing/TT chainring... What's up with that? [Gary Tingley] [ In reply to ]

Jul 25, 04 7:54

Post #4 of 15 (2032 views)

shameless plug, Gary!

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Re: Julich's climbing/TT chainring... What's up with that? [Gary Tingley] [ In reply to ]

Jul 25, 04 8:56

Post #5 of 15 (2012 views)

Would Bobby J's chainring produce similar results as Rotor Cranks?

Dave from VA

Re: Julich's climbing/TT chainring... What's up with that? [DC Pattie] [ In reply to ]

Coggan's Heroes

Jul 25, 04 9:34

Post #6 of 15 (1989 views)

seems like they produce the exact same advertised benefit as rotorcranks. Rotorcranks are just a heavy, complicated (more moving parts=higher chance of mechanical failure), and expensive way of achieving the same benefit.

Re: Julich's climbing/TT chainring... What's up with that? [Ben in FL] [ In reply to ]

....

Jul 25, 04 9:47

Post #7 of 15 (1971 views)

they are made by osymetric and were first sold under the name harmonic (and available on many of the castorama bikes for instance)

www.osymetric.com

Re: Julich's climbing/TT chainring... What's up with that? [Ben in FL] [ In reply to ]

Jul 25, 04 11:55

Post #8 of 15 (1880 views)

"seems like they produce the exact same advertised benefit as rotorcranks. Rotorcranks are just a heavy, complicated (more moving parts=higher chance of mechanical failure), and expensive way of achieving the same benefit. "

They do not work at all like Rotors, as they do not eliminate the dead point, see below:

Re: Julich's climbing/TT chainring... What's up with that? [Gary Tingley] [ In reply to ]

Jul 25, 04 12:22

Post #9 of 15 (1857 views)

Khai

I saw it on OLN , it seemed just an Elliptic gear cut for the power of the rider , they made a cheap version in the 80s biogear -biomet - ? The builder said it was supposed to even out the flat spot / even power stroke.

Re: Julich's climbing/TT chainring... What's up with that? [Helitech] [ In reply to ]

Jul 25, 04 13:30

Post #10 of 15 (1821 views)

I think it was called "Bio-Pace".. We should start a thread "Old school equipment"

Re: Julich's climbing/TT chainring... What's up with that? [Gary Tingley] [ In reply to ]

Coggan's Heroes

Jul 25, 04 14:59

Post #11 of 15 (1778 views)

Looking at you animation, the crank still passes through the dead spot, so it is not eliminating it, just accelerating the crank thru it.

Ovalized cain rings are probably more effective becuase they accelerate both dead spots evenly and at the same time, at the 12 oclock, and 6oclock.

Re: Julich's climbing/TT chainring... What's up with that? [Ben in FL] [ In reply to ]

Jul 25, 04 15:12

Post #12 of 15 (1765 views)

no, it is eliminated, the dead spot occurs at 12 and 6, Rotors have no 12 and 6 alignment

Re: Julich's climbing/TT chainring... What's up with that? [Gary Tingley] [ In reply to ]

Jul 25, 04 16:38

Post #13 of 15 (1722 views)

Ben in Fl wrote

Ovalized cain rings are probably more effective because they accelerate both dead spots evenly and at the same time, at the 12 oclock, and 6oclock.

I rode a bio-pace crank a few hundred miles, I think it reduced the pressure at the dead spot, but had a weird feel climbing. but its a soild crank arm / no swing. Its was not right for me as the arms were short 170 mm.

Re: Julich's climbing/TT chainring... What's up with that? [Gary Tingley] [ In reply to ]

Coggan's Heroes

Jul 25, 04 17:26

Post #14 of 15 (1689 views)

no, really, it's not eliminated.

Re: Julich's climbing/TT chainring... What's up with that? [Ben in FL] [ In reply to ]

Jul 26, 04 5:18

Post #15 of 15 (1552 views)

There is not a power void in Rotor Cranks as there is with traditional cranks

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