Froome's chainrings on Stage 9

[Bruce K]

I can't tell if he was using Osymetric or Rotor, but definitely he was using the asymmetric big ring in the mountains.

Does anyone know the brand/model and tooth count?

BK

[Bruce K]

Found it - Osymetric on SRM power meter

Still not sure of tooth count

Anyone gave any experience with these? Also, if you put it/them on one of your bikes, should you switch them all?

Just curious

BK

[macaroon]

Hope this helps

http://www.cyclingweekly.co.uk/news/latest/539297/chris-froome-s-tour-de-france-weapons-of-choice.html

[FlashUNC]

Couple local guys swear by them. I have a hard time thinking they shift worth a darn. And set-up, from what I've seen, can be a little wonky.

But like I said, I know guys who would rather part with their grandmother than those rings.

Made locally in NC to boot.

[Bruce K]

I have heard that there are shift issues

The rings are not ramped or pinned

They certainly have my curiosity but it also sounds like it's a significant purchase for one set - forget multiple bikes and I think, the more I read, that it is an all or nothing deal. You can't just do one bike.

BK

[FlashUNC]

Given the extreme shape, folks seem to have the best luck using a compact derailleur with a larger cage that can better handle the extreme eccentric movement.

I would think a chain catcher of some kind would be a must.

[AngryScientist]

i'm a proponent of a traditional outer ring, oval inner ring. it's the climbing secret weapon. for me, or at least in my head, i can get into a better rhythm on long climbs with the rotor ring, the regular outer ring preserves shifting greatness.

i only have this set-up on one bike though.

[victoryfactory]

Watching his chain bounce as it went around the chainring
was un nerving in close-ups. It looked like it would fly off.

VF

[Bruce K]

Nick

What size rings are you using? What brand(s)

It seems that Osymmetric only goes down to 42t and that doesn't 't seem much like a climbing setup

BK

[TPetsch]

I also noticed that his crank arms -stage 9- looked shorter than what I would imagine for tall guy like Froome, very anti-Zinn philosophy is what I thought :)

[FlashUNC]

I also noticed that his crank arms -stage 9- looked shorter than what I would imagine for tall guy like Froome, very anti-Zinn philosophy is what I thought :)

I noticed that too. Seemed like he was using 170's or something similarly short. Though his proportions don't do his pedaling stroke any favors.

[regularguy412]

I noticed that too. Seemed like he was using 170's or something similarly short. Though his proportions don't do his pedaling stroke any favors.

Right. Did you see the super high cadence he put in when responding to attacks? It looked 'so' inefficient, but I guess it works for him. All those revs 'must' use up a ton of VO2.

Mike in AR:beer:

[jimcav]

Right. Did you see the super high cadence he put in when responding to attacks? It looked 'so' inefficient, but I guess it works for him. All those revs 'must' use up a ton of VO2.

Mike in AR:beer:

but no big deal with the various ways to keep the hematocrit at 50 :)

I now love watching the tour and wondering what test they will run on the blood in 5-10 years.

[regularguy412]

but no big deal with the various ways to keep the hematocrit at 50 :)

I now love watching the tour and wondering what test they will run on the blood in 5-10 years.

Precisely!

A little sludge that resembles blood makes everyone faster -- if it doesn't kill ya.

Mike in AR:beer:

[false_Aest]

Shh! There's a motor in those chainrings.

[rwsaunders]

Some more Froomeformation...

http://www.bikeradar.com/news/article/pro-bike-chris-froomes-pinarello-dogma-651-think2--37547/

[Bob Ross]

Couple local guys swear by them.

I've met three guys who use them: A CAT1 monster, a super-smooth CAT3 buddy who's possibly one of the smoothest wheels I've ever ridden with, and a complete stranger who I met on an ascent of Mt Lemmon who was really nice and quite the athlete blah blah blah...

All three of these guys absolutely swear by asymetric chainrings like they're the greatest thing since sliced bread...no doubt in their minds that it's a major improvement.

And yet I just can't get past the complete ridiculousness of the whole idea...

[pbarry]

Surely someone of Froome's caliber wouldn't be using them without wattage data supporting their superiority, or would they?? However, all I can think of is Yogi Berra's best quote ever and Shimano Biopace.

[FlashUNC]

I've met three guys who use them: A CAT1 monster, a super-smooth CAT3 buddy who's possibly one of the smoothest wheels I've ever ridden with, and a complete stranger who I met on an ascent of Mt Lemmon who was really nice and quite the athlete blah blah blah...

All three of these guys absolutely swear by asymetric chainrings like they're the greatest thing since sliced bread...no doubt in their minds that it's a major improvement.

And yet I just can't get past the complete ridiculousness of the whole idea...

It must be like what Scientology is like.

These guys are just into it man.

[merlinmurph]

Hey BruceK,
I was at a friends house this weekend and noticed she had an old bike with Biopace rings on it. I told her she could get some good money for 'em. For you, how 'bout $50 apiece? :)

Enjoy your ride,
Murph (a non-believer)

[Louis]

If you read French, this is an interview with a TDF publicity caravan "girl."

It actually sounds like a pretty tough job. They were once pissed on by some (presumably drunk) Basque fans as they came out of a tunnel...

http://tourdefrance.blog.lemonde.fr/2013/07/08/on-nous-traite-de-cochonnes-mais-cest-plutot-sympa/

http://tourdefrance.blog.lemonde.fr/files/2013/07/grosplan.jpg

[jgspin]

I replaced my 36 tooth inner with a 38 tooth Osymetric to go with my round 52 tooth 110 BCD outer. I didn't want to buy both just in case I didn't like it. The back is an 11-32. I didn't have to adjust my FD. I had to install a chain catcher to prevent dropping the chain in the 38x32. Currently the chain rubs a bit when in the 38x32. I've been too lazy to redish the rear as I will be changing my crankset to another that will get the drive side more towards the frame to eliminate the chain rub. I've had no shifting problems as my big ring is ramped and pinned.

To date I've ridden about 750 miles with it. The first time I used the osymetric, it felt really weird. Spin didn't feel right, like there was a void where my feet would speed up at the BDC. It felt like square pedaling. The "scrape the mud" pull felt disconnected from the whole of the pedaling. This was the on flats. On the hills; wow there is a difference. With resistance from the the grade it was more comfortable. Bigger gear was easier to climb with as the back pull seemed unnecessary. It was more push push and power stroke with every pedal.

Out of the saddle was really smoother. On the regular round ring I would get to the BDC and my other leg was not ready to pedal because I would get to the BDC so fast, so it was a noticeable thud, thud. With the Osymetric the power stroke was longer so by the time my foot was at BDC my other foot was ready to pedal. It is much smoother and allows me to stay out of the saddle longer. I could climb Scripps Poway Grade out of the saddle all the way to the top since I don't feel as gassed.

For me rpm on the osymetric above 85 does not feel right. So it's ideal for me on climbs where my cadence depending on the grade in/out of the saddle could be 60-80. In the flats on my round big ring I'm comfortable at 80-105 rpm.

[liray]

Makes me want to try out the cheaper Doval chainrings... Using just one as the inside chainring for climbing seems to be an interesting idea...

[ahpook]

yup 'biopace' is all i can think too. early influence of sheldon brown, i guess.

i rescued this biopace-equipped bike a few years back and built it up for my neighbor. the pink and teal reminded me of a nagel airbrush painting from the 80s.

http://farm4.staticflickr.com/3271/2896614001_b8e9c350b0_z.jpg

[Bruce K]

Nope, no Biopace.

Our coach is not a fan of non-round rings either.

It seemed interesting to me that someone like Froome would use these unless there was a real (in which case they would use them) or perceived advantage.

I am intrigued by the idea of the inner ring for climbing but would like to find more data on tooth count equivalents, etc.

At this point it seems that Osymmetric is offering a new, thicker ring that has less flex but only as sets in 130bcd

BK

[soulspinner]

The team is so loaded they made their own stem measurement device.........:p

[oldpotatoe]

but no big deal with the various ways to keep the hematocrit at 50 :)

I now love watching the tour and wondering what test they will run on the blood in 5-10 years.

No test for blood boosting, using your own blood. The doping of choice these days, IMHO. Froome looks scary, seeing his team evaporate and being able to hold off 5 Movistar guys...WE'll see how he does the next mtn satge after the next one. If he comes out swinging again, while his team disappears...well...

[J.Greene]

No test for blood boosting, using your own blood. The doping of choice these days, IMHO. Froome looks scary, seeing his team evaporate and being able to hold off 5 Movistar guys...WE'll see how he does the next mtn satge after the next one. If he comes out swinging again, while his team disappears...well...

Froome was kicked out of the 2010 Giro for holding onto a motorbike. Nice improvement over 3 years. You mean its not the chain rings? #sarcasm

[jvp]

Durham elliptical from the 1970s.

http://velobase.com/CompImages/CrankRing/B7C758B9-C6D9-4D86-B3BD-9E82CB4ED9CC.jpeg

[josephr]

Loving this thread....all you guys that dismissed Biopace back in the '80s and '90s are loving you some Fromme asymetricals!

Long live Sheldon Brown!!!

[TAW]

i'm a proponent of a traditional outer ring, oval inner ring. it's the climbing secret weapon. for me, or at least in my head, i can get into a better rhythm on long climbs with the rotor ring, the regular outer ring preserves shifting greatness.

i only have this set-up on one bike though.

Only wimps climb in their small ring. ;)

[Bruce K]

Spoken by a man from the mid-west..... ;)

And while New England isn't the Rockies......

BK