26 January 2014

Pedaling Rectangles, Osymetrically

Winter view from North side of Lake Tsukui.  Snow toward Mt. Tanzawa.
On Saturday, the weather was its warmest in weeks.  Even with a layer of clouds, it was over 10 degrees (C) in the Sagamiko/lower Doshi area.  I rode out Onekansen Doro, north side of Lake Tsukui, up Doshi Michi, then onto Kanagawa Route 76, then Route 517.  Then back of Otarumi Pass, through Takao, along the Asagawa and home.  About 135 kms in all, on well-traveled routes.

Tall, dry Susuki grasses along Route 76 in winter.
This time, I had a new toy.

I've had an NOS (new old stock) FSA Team Issue standard size crankset (130 BCD/172.5mm arms) sitting in the garage for years.  It was a warranty replacement provided when the original (an earlier design) had a problem with the left crank arm delaminating.  For Christmas, I finally got myself some chainrings for this crankset.  Instead of yet another 53/39 crank, I ordered a set of Osymetric chainrings.

Osymetric chainrings?  These are what Bradley Wiggins (excuse me, I meant Sir Bradley Wiggins) and Chris Froome each used in 2012, when they finished 1-2 in the Tour de France.  Sir Bradley also used them during his gold medal performance in the London Olympics TT.
52/42 rings.  But the 42 ring is quite narrow where you pedal through your "dead spot".
The general idea is that your legs are like the pistons of an engine, so chainrings should be more like cams, with the shape of the ring to match the part of your pedal stroke where your legs deliver the most/least power. The shape is irregular, but you can almost see 4 sides with rounded transitions.  The inventor, a small French company, has some fairly extravagant claims.

The earliest versions were said to look home-made, and the majority opinion was that they look odd, weird, or ugly.  But the current version looks solid and professionally finished, and in a black finish other riders will barely notice the shape.

Reviews are not clear about whether the effect is real or a gimmick.  Some riders have an immediate positive reaction.  And the idea is simple.  At least if Wiggins and Froome used them in 2012 then at least they cannot do much harm!  Wiggins dropped them in 2013.  Froome -- seems to be using them as he crests Mt. Ventoux, one of the most memorable performances in recent history of the Tour.  They seem more popular with long-legged riders, whose angle of motion is slightly different.
Froome at Mt. Ventoux.  See chainring.
Arashiro bottles
They were easy to install, and with a minor adjustment of the front derailleur (moving it up the seat tube so there would be enough clearance at the largest part of the chainring) they shift fine.  It takes a big push of the front derailleur lever to get up on the big ring, but a minor cable adjustment should help.
And no, the chain does not fall off.

TT warmup
I had an almost immediate positive reaction.  The pedalling motion felt different only for a few minutes, pulsating, almost.  But quickly the difference is barely noticeable.  Except I did feel as if it was easier to push the pedals than usual.  I could spin to accelerate beyond normal speed/cadence without the straining my muscles as much as I otherwise would have.  I think I could perhaps reach and sustain a higher cadence with this shape of chainring.  Of course, in reality, my cardio limit quickly becomes apparent, so I am not sure that I end up riding any faster.  But even if the limiting factor is my cardio system, over a long ride I think less strain on the leg muscles can only help.  And with a bit of practice I might learn to climb sustainably without my enthusiasm pushing into the red zone.

Looking at the data for my ride Saturday ... I rode no faster than normal.  Will I keep these on my bike?  Can I climb the Japanese hills with a 42-tooth inside chainring?  It is too soon to decide.  Even if they do increase my speed a bit, I worry a bit that using them while training will just keep my dead spot ... dead.  But maybe if they let me work on pushing my cardio limit without working so much about leg fatigue, they will help?  And they might have real benefits for an event -- either a race or a multi-day, really long ride like LEL, PBP or Hokkaido 1200?  Stay tuned.

UPDATE:  On Monday morning, I hopped on a different bike for the commute to work, with a Shimano 50/34 compact crank.  For the first minutes, it felt WEIRD.  Just as odd as the first few minutes on the Osymetrics.  I am really surprised that I "adjusted" to the Osymetrics so quickly.  Of course, after 2-3 minutes, again I felt normal on the round cranks.


Manfred von Holstein said...

I could have waived at you from the Tanzawa peaks! Had a great time up there hiking while you were on your bike.

As for the osymmetric chain rings, they were already promoted when I was a child - i.e. a very long time ago. They touted the same benefits you mention and I was quite interested, but as I wasn't cycling that much, I never got them.

David L. said...

From what I have read, Osymetric first came out in 2003. One of the linked articles from the post quotes:

"Yeah, I was the first guy to use them, back in 2003, and then I used them for the rest of my career," recalls Julich,


I think you may be remembering the Shimano Biopace, an early take on the irregularly shaped chainring. (Rotor's Q-rings being a third).

See: http://www.sheldonbrown.com/biopace.html

Manfred von Holstein said...

Yes, indeed - that's what they were called. How are they different?

David L. said...

How are they different? Each of the articles mentions, I think. To quote Cycling Tips:

What about Biopace?

This is the first question that everyone will ask Jean-Louis. As he explains, Biopace was the exact opposite as Osymetric. It was totally wrong from a biomechanical perspective. First of all because it was oval. According to Jean-Louis, a shape needs to be created that is fitted to the pedal stroke – and that shape is not oval. Secondly, Biopace set the crank in line with the large edges of the chainring. With Bio-Pace you actually lost power.

CM said...

Any more thoughts about Osymetric chain rings?

Have you used them again since January of 2014?

I am quite curious about trying them myself.

David Litt said...

Hi CM:

I used them a fair bit in 2014 through the Fleche and beyond. I had a bit of problem with chain drops when they got out of adjustment ... but managed to fix that by adjusting the FD. I took them off for a 50-34 compact set for some very mountainous rides, and more recently have been enjoying my Ultegra 6800 setup on the Canyon.

I think the Ossymtrics would be ideal in a time trial or long relatively flat event -- definitely seem to pedal better through the dead spot and could probably eke out a higher sustained maximum speed. I will get them out again soon and might even put them on my Ti travel bike before some kind of major effort ...