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Slowtwitch Forums: Triathlon Forum:
ROTOR cranks vs O.SYMETRIC chainrings

 

   


Sergio Escutia

Nov 9, 05 7:01

Post #1 of 22 (6472 views)
ROTOR cranks vs O.SYMETRIC chainrings Quote | Reply

Seems that both are UCI aproved. I am interested in opinions regarding these two crank systems.

Is Julich still using O.SYMETRIC chainrings? Who is the distributor for O.SYMETRIC in America?

Thanks beforehand for your comments,

Sergio
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Note: English is not my first language. Please read this translated post considering that.




Rappstar

Nov 9, 05 7:17

Post #2 of 22 (6460 views)
Re: ROTOR cranks vs O.SYMETRIC chainrings [Sergio Escutia] [In reply to] Quote | Reply

You can add Rotor Q-rings to the mix. They are Rotor's answer to the Osymetric.

Yes, Bobby still uses Osymetrics.


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Sergio Escutia

Nov 9, 05 15:07

Post #3 of 22 (6394 views)
Re: ROTOR cranks vs O.SYMETRIC chainrings [Rappstar] [In reply to] Quote | Reply

Thanks for the information. I had not noticed that ROTOR had that type of chainring.

There seems to be a considerable shape difference between the ROTOR Q-Rings and the O.SYMETRIC.

I wonder who would get a greater benefit from these chainrings. Cyclist that ride at below normal cadence or to those that ride at a higher cadence?

Sergio
-------------------------------------------------------------------
Note: English is not my first language. Please read this translated post considering that.




Rappstar

Nov 9, 05 15:20

Post #4 of 22 (6379 views)
Re: ROTOR cranks vs O.SYMETRIC chainrings [Sergio Escutia] [In reply to] Quote | Reply

Lower cadence. At high cadence, your time in the deadzone near 12 & 6 is much less than at low cadence, so the effect of the rings is less.

Pablo Carrasco, the founder of Rotor, said as much. He found a notable advantage using Q-rings when climbing but saw no advantage on the flats. That may be tied to both cadence and torque. But they are definitely better for mashers than spinners...


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Avago

Nov 9, 05 15:51

Post #5 of 22 (6346 views)
Re: ROTOR cranks vs O.SYMETRIC chainrings [Sergio Escutia] [In reply to] Quote | Reply

Sergio,

are these for your teenage son?

if so I would suggest that you leave him on his conventional cranks & restricted gearing for a few years more. there is no need to submit his still developing body to any additional strains.

there are enough stresses & strains with tri training as it is.

btw, I use rotorkranks on my roadie & tri bike. I think they're great but for a youngster, not really necessary.

avago


Sergio Escutia

Nov 9, 05 17:31

Post #6 of 22 (6300 views)
Re: ROTOR cranks vs O.SYMETRIC chainrings [Avago] [In reply to] Quote | Reply

What you wrote sounds logical Rappstar.

Avago, I was thinking that these chainrings maybe would lower the chance of him getting hurt and not the other way. I fully agree that it is very important to keep him from overtraining and away from the risk of injury. He is so full of energy and so excited about his constant and fast improvement in his performance that I must constantly warn him of not training too hard (like today that he asked for permission to ride home after the training ride). I have been warned by very knowledgeable cyclists about the risks of him taking it too seriously at such young age. I do not plan to let him go from triathlete to full time cyclist (as he wants now) until he turns at least 16 years old.

As I mentioned before he is restricted to a 40/14 (chainring/cog) for road races and to a 44/14 for triathlon events. Today he rode for the first time with the 6.1 m restricted "road racing" rollout. He is very upset about having to ride under such short rollout, but I think that it will help him improve his pedaling skills and maybe lower the risk of injury.

Thanks for your comments.

Sergio
-------------------------------------------------------------------
Note: English is not my first language. Please read this translated post considering that.




Tom Demerly

Nov 9, 05 18:06

Post #7 of 22 (6283 views)
Re: ROTOR cranks vs O.SYMETRIC chainrings [Sergio Escutia] [In reply to] Quote | Reply

Another question I was interested in investigating is how well the Rotorcrank chainrings work. They seem somehow similar to O.Symetric.

Tom Demerly
Editor, TriSports University
http://university.trisports.com/


Meebo

Nov 9, 05 18:48

Post #8 of 22 (6254 views)
Re: ROTOR cranks vs O.SYMETRIC chainrings [Avago] [In reply to] Quote | Reply

In Reply To:
Sergio,

are these for your teenage son?

if so I would suggest that you leave him on his conventional cranks & restricted gearing for a few years more. there is no need to submit his still developing body to any additional strains.

there are enough stresses & strains with tri training as it is.

btw, I use rotorkranks on my roadie & tri bike. I think they're great but for a youngster, not really necessary.

avago


I agree that kids should be kids and not train like adults, but which system do you allege creates additional strains and why?

If both systems are allegedly better for lower cadence then wouldn't they benefit younger riders who tend to ride with lower cadences?


Rappstar

Nov 9, 05 19:05

Post #9 of 22 (6242 views)
Re: ROTOR cranks vs O.SYMETRIC chainrings [Diablo-Advocato] [In reply to] Quote | Reply

Rotor cranks and q-rings place a much greater load on the thighs during the "drive" portion than traditional cranks. That is why they might not be good for kids. Idea of minimizing rollout is to reduce stress on young muscles and joints. These systems do not do that...


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Avago

Nov 9, 05 19:08

Post #10 of 22 (6241 views)
Re: ROTOR cranks vs O.SYMETRIC chainrings [Diablo-Advocato] [In reply to] Quote | Reply

In Reply To:
In Reply To:
Sergio,

are these for your teenage son?

if so I would suggest that you leave him on his conventional cranks & restricted gearing for a few years more. there is no need to submit his still developing body to any additional strains.

there are enough stresses & strains with tri training as it is.

btw, I use rotorkranks on my roadie & tri bike. I think they're great but for a youngster, not really necessary.

avago


I agree that kids should be kids and not train like adults, but which system do you allege creates additional strains and why?

If both systems are allegedly better for lower cadence then wouldn't they benefit younger riders who tend to ride with lower cadences?


(This post was edited by Avago on Nov 9, 05 19:12)


Record10Carbon

Nov 9, 05 19:22

Post #11 of 22 (6230 views)
Re: ROTOR cranks vs O.SYMETRIC chainrings [Rappstar] [In reply to] Quote | Reply

I bet BioPace hits a new level on Ebay...
----------------------------------------------------------

What if the Hokey Pokey is what it is all about?


Meebo

Nov 9, 05 19:24

Post #12 of 22 (6222 views)
Re: ROTOR cranks vs O.SYMETRIC chainrings [Rappstar] [In reply to] Quote | Reply

In Reply To:
Rotor cranks and q-rings place a much greater load on the thighs during the "drive" portion than traditional cranks. That is why they might not be good for kids. Idea of minimizing rollout is to reduce stress on young muscles and joints. These systems do not do that...
O.symetric as well?


Rappstar

Nov 9, 05 20:05

Post #13 of 22 (6202 views)
Re: ROTOR cranks vs O.SYMETRIC chainrings [Diablo-Advocato] [In reply to] Quote | Reply

They all make the chainring "bigger" during the "drive." That is how they work. I'd be nervous with anything that was designed to do that. Plus their bodies are so adaptive, you might force them to adapt to that style ring, and they'd always suffer as a result in the future.


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Meebo

Nov 9, 05 21:27

Post #14 of 22 (6179 views)
Re: ROTOR cranks vs O.SYMETRIC chainrings [Rappstar] [In reply to] Quote | Reply

In Reply To:
They all make the chainring "bigger" during the "drive." That is how they work. I'd be nervous with anything that was designed to do that. Plus their bodies are so adaptive, you might force them to adapt to that style ring, and they'd always suffer as a result in the future.


Or do, for example, the O.Symetric make the chainring normal during the drive and smaller during the non-drive phase, assuming "drive" is the push portion of the stroke?

And isn't that an oxymoron... if they're so "adaptive" then when they go back to other rings they adapt (and not "suffer")...


JDub

Nov 9, 05 23:15

Post #15 of 22 (6151 views)
Re: ROTOR cranks vs O.SYMETRIC chainrings [Rappstar] [In reply to] Quote | Reply

To clarify my understanding, Rotorcranks use a circular chainring and speed your foot through the dead zone in the 12:00 position only, while keeping the remainder of the stroke at the same speed, while ovalized chainrings quicken the pedal stroke at both the top and bottom of the stroke? Other than the different mechanical method used, the effect is approximately the same??


Rappstar

Nov 10, 05 7:16

Post #16 of 22 (6096 views)
Re: ROTOR cranks vs O.SYMETRIC chainrings [Diablo-Advocato] [In reply to] Quote | Reply

It would depend on the size you used as to whether or not they did what you said. The equivalent chainring size makes them smaller during the "weaker" parts and larger during the drive. So a 53 is equivalent to a 56 at the big point and 50 at the smallest (it depends on which setting you use). So if you sized down (say a 50 QRing), then you could make it so the biggest they ever got was as big as your normal ring and the smaller was much smaller. However, then you would be further reducing the overall gear inches, and since the kids are on shortened roll-out anyway, that doesn't seem like a useful idea.

Read any of Ed Burke's books, all of which cover the subject. Ovoid change rings are best for low-cadence, high-power pedaling, which doesn't seem to me like what you want to be subjecting young bodies to.

Regarding adapatation, they ride on reduced rollout as Juniors, when their bodies are learning. If they ride these rings are Juniors to give them an edge, that is the pedal stroke they will learn. And then if you take them off once they graduate from Juniors, when their bodies are no longer so adaptive, then you have committed them to this equipment. The habits they develop as kids become harder and harder to shake as they get older.


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Rappstar

Nov 10, 05 7:20

Post #17 of 22 (6089 views)
Re: ROTOR cranks vs O.SYMETRIC chainrings [JDub] [In reply to] Quote | Reply

http://www.rotorbike.com/eng/simulador_RS4_RD2_53.htm

http://www.rotorbike.com/Q/home.htm

That's the manufacturer's definition of what happens. They are slightly different because with RotorCranks, you actually are pushed by the cams through the deadspot at 12. With the rings, you are essentially just pushing a smaller ring.


"Non est ad astra mollis e terris via." - Seneca | rappstar.com | Facebook - Rappstar Racing | @rappstar | WTC Ironman Pro Ambassador

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Sergio Escutia

Nov 10, 05 7:23

Post #18 of 22 (6085 views)
Re: ROTOR cranks vs O.SYMETRIC chainrings [Record10Carbon] [In reply to] Quote | Reply

In Reply To:
I bet BioPace hits a new level on Ebay...


Maybe not if they find this definition of BioPace from the THE DICTIONARY OF MOUNTAIN BIKE SLANG ;) .

biopace adj. a now-discredited Shimano techno-fad where the chainrings
were intentionally made non-circular--instead, they were elliptical,
in order to (allegedly) smooth the power delivery, by giving the rider
an effectively lower gear for part of the spin cycle. Now used to
describe any uneven pedaling motion. Also used as a synonym for
pogo-ing.


Another quote from a source I could not ID:

Biopace chainrings have fallen into disfavor in recent years. They
are hard to "pedal in circles". The early Biopace chainrings were
designed for cadences of around 50-70 rpm, while most recommend a
cadence of 80-100 rpm. Newer Biopace chainrings are less elliptical,
but the general consensus is to (if you are buying a new bike) get the
dealer to change the chainrings to round ones.


It is clear now that BioPace, Rotor Q-rings and O.SYMETRIC are "non-round" chainrings but perform differently.

I found in my search plenty "non-round" detractors, but then you read comments like Sheldon Brown's "Non-round chainwheels remain controversial, especially among racers who think that everyone should ride racing bikes, but, in my opinion, they are of real value for the vast majority of non-racing cyclists."

And then you see Bobby Julich riding O.SYMETRIC.

Sergio
-------------------------------------------------------------------
Note: English is not my first language. Please read this translated post considering that.




cyclingfrenchie

Nov 10, 05 9:10

Post #19 of 22 (6041 views)
Re: ROTOR cranks vs O.SYMETRIC chainrings [Sergio Escutia] [In reply to] Quote | Reply

Hi Sergio,

I thought I would chime in 'cause I used Osymetric chainrings last winter and have been using Rcs for two months now.

I believe the Osymetric chainrings do work from a physiological standpoint, especially while climbing (lower cadence). Pb is, I think they were way too ovalized (around 22%) to work for me gear-wise: I got chain skipping issues that I was unable to solve (changed the cogset, put a new chain, cleaned and lubed the cables,etc: you name it, I tried it, and to no avail). But Bobby Jullich does not seem to mind, so I might have been unlucky.

I then bought RCs, they take a little more time to adapt to (I am still adapting I guess) but from the first ride I could tell they would "work" even better than the Osymetric's. I have no data to back it up because this is still my off-season, but they seem to flatten the long drags, and climbing out of the saddle is a blast.

I am looking forward to smashing my Mt Ventoux PR next year ;-).

As for the Q-rings, I have not tried them but as far as I can see they are far less ovalized than osymetric's (less than 10% I guess), so this means less chain- and cog-related issues in my book.

There, my EUR 0.02. Hope this helps.

_________________________________________________

Pardon my French.


KenMierke

Nov 11, 05 5:12

Post #20 of 22 (5996 views)
Re: ROTOR cranks vs O.SYMETRIC chainrings [cyclingfrenchie] [In reply to] Quote | Reply

I'll be writing an article comparing the benefits of Powercranks, Rotor Cranks, and O symmetric for Velo News next spring and I'd love any imput anyone wants to send me at CoachKen@erols.com

Thanks,

Ken
Ken Mierke
Head Coach, Fitness Concepts
http://www.Fitness-Concepts.com
Author, The Triathlete's Guide to Run Training


Bretom

Nov 11, 05 6:00

Post #21 of 22 (5978 views)
Re: ROTOR cranks vs O.SYMETRIC chainrings [Rappstar] [In reply to] Quote | Reply

I'm sure you and Pablo are right on this but I don't quite understand the point about these systems being of greater benefit to mashers - sure, on each stroke you spend less time at higher cadences but if you cover the same ground at the same speed surely your total time in the deadspot will b the same as you'll have taken ore pedal strokes?


"Are you sure we're going fast enough?" - Emil Zatopek


harlman

Nov 11, 05 6:24

Post #22 of 22 (5967 views)
Re: ROTOR cranks vs O.SYMETRIC chainrings [Sergio Escutia] [In reply to] Quote | Reply

Is there any objective evidence whatsoever that any of these non-traditional "systems" actually make you faster? IMHO that seems to be the very first question to ask before even considering changing from traditional cranks/chainrings.

   
 
 
 



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