Elliptical chainrings

jburbatt

So I was reading a review of the Rotor 3D crankset in Lava, and while interested in the idea that an elliptical chainring could increase your power up to 3%, I was actually more intrigued by the idea of reduced knee stress since I had signifcant issues with knee problems on the bike last year.  Has anyone used an elliptical chainring before?  What was your experience (both in stress on the knee and power output)?

ghernand

hi jennifer,

i used elliptical rings for 1 year on a compact crankset.  now i use normal round rings.

the only power leverage advantage that i found was with climbing when standing in the small chain ring.  since i almost never stand when i climb in my races, i opted to return to round rings.  also, the front derailleur shifting was never as good as with the round rings, due to the big jump from the big elliptical ring to the small elliptical ring, the both of which are set at different elliptical leverage points.

if after researching them more, you decide to try them, i still have mine for compact and i can sell them to you for really cheap.

safe training,

gh

 

Peter Greagg

Hi Jennifer — some of my tri buddies starting to use them last year and were impressed by them.  They reported that they thought they could maintain a higher average speed in Olys and sprints.  Neither of them have knee issues.

So I took the plunge and bought Rotor Q rings in a compact size.  I have used them in two HIMs and the ABP rides for three months.  I have a significant knee issue (dodgey ligaments and little cartilage in right knee) and the Q rings are certainly easier to turn-over the dead-spot.  You can adjust them but I haven't felt the need to do so.  If I was going to adjust them I would use my Computrainer Spin Scan.

In terms of racing, I am improving witrh each race, but that is probably mostly because I starting to drink the Kool Aid in May 2010.

I noticed in the Tour time trial stages, most rider appeared to use them.

Hope this helps.

Cheers

jwpicciotto

This is a concept that comes around every few years. Unfortunately that is not a lot of solid information to back them up. Some studies say they work, some say they don't. Before you go out and spend the money, you might have someone evaluate your pedal stroke and work on that first to address the knee issues. Some of what I have heard is that the chain rings try and force you into a fuller pedal stroke. This is something that you can do on your own without mechanical aid.

In the end, I think that it is personal preference.

jburbatt

Thanks guys! I think I'll wait until there's some more information out there on the benefit for knee problems. I had some issues last year, but from my guess it was because I let my knee strengthening program go by the wayside while training. I'm trying to remedy that this year. I'll stick with the regular rings and hope that an upgraded shifting system helps too (upgraded to one that works this year ).

ghernand

Jennifer:

Sorry, I skipped over your knee issue and jumped right to the performance
Question.

Anyway, post in the medical forum if you want some added perspectives
Regarding your knees. I always pause when an active person
Is put on a knee strengthening program.

William Jenks

A question I've had about these is that - ultimately - watts aren't free.

If you really raise your FTP by (let's say) 3%, that's huge. But if, instead, your FTP is the same, but your watts at a particular PE are 3% higher, it's not clear to me that this is much benefit besides pychological. In fact, it might trick you into riding too hard.

This is independent of the knee issue.

Does anyone know of studies that really document an increase in FTP? I can't help but think if it were really free speed like that that everyone would have them.

jburbatt

Posted By Gilberto Hernandez on 17 Jan 2011 10:09 PM

Jennifer:



Sorry, I skipped over your knee issue and jumped right to the performance

Question.



Anyway, post in the medical forum if you want some added perspectives

Regarding your knees. I always pause when an active person

Is put on a knee strengthening program.

 

I had an ACL reconstruction using my patellar tendon done in 2003, so I have issues with recurring tendonitis and water on the knee from the repetitive motion on the bike (and then overcompensating for the pain with my other knee- ahhhh fun).  When I do active strengthening stuff I have fewer problems.  But, when I slack off and increase distance too fast is when I start to have more problems so I'm trying very hard this year to stay on top of it.  I have had them fully checked out by a sports doc and we developed these protocols to hopefully minimize any issues this year.  Fingers crossed!

Jenn Edwards

Hi! 

Sorry to drag this up again.  I'm a facts and data girl and hesitant to jump into a big change like this unless I have DATA!  *** Visualize image of Gollum crooning over "my precious data" here. ****

Of course, sometimes data means "your results may vary" so I'm open to that too. So I read the studies below still didn't come to a conclusion which leaves me unlikely to make a change.  Perfect knees, BTW (knock on wood and sorry for yours knee woes Jennifer . 

Any other thoughts from the popcorn gallery on this?

Thanks much!  

http://www.ncbi.nlm.nih.gov/pubmed/21266731



http://www.ncbi.nlm.nih.gov/pubmed/18395213



http://www.ncbi.nlm.nih.gov/pubmed/19184083



http://www.ncbi.nlm.nih.gov/pubmed/17768635



http://www.ncbi.nlm.nih.gov/pubmed/17703998



(this one doesn't really know what it's testing:http://www.ncbi.nlm.nih.gov/pubmed/17369796)



This is the only field one: http://www.ncbi.nlm.nih.gov/pubmed/16846753



http://www.ncbi.nlm.nih.gov/pubmed/12955523



(old Biopace: http://www.ncbi.nlm.nih.gov/pubmed/1435158)

Peter Greagg

Hi Jenn — I notice no one has answered you, so in addition to my post of 15 Jan, that I still have them on my TT bike.
Conceptually, I believe there could be some benefit from them (in theory at least) as they can help smooth out your pedal stroke thereby damping the amplitude of the power spike, at a give power output (make sense?). This is the reason peeps do one legged drill etc
I will soon be using my Computrainer to dial them in.
I guess the big question for me is "Will I replace my Eliptical rings when they are worn out?"
The answer is probably.
BTW, didn't Coach P use rotor rings at Kona?

Pina

I'll put my 2 cents in here. I've been riding on Rotor Rings for the past 8 months. I didn't purchase them to increase my FTP, but to get into a more aggressive TT position. I was able to drop my torso 3 degrees while holding the same hip angle at 12 o clock. (I've been professionally fitted and worked with my bike fitter on this) immediately I personally had an increase in my FTP by 1-2%. Did the rings do this? Was it motivation? Was I just having a better day???? SO tough to measure objectively, my answer, I don't know... But my FTP has climbed significantly since then so I'll never truly know (That's from training with a power meter).

What I can say objectively, is that I was able to drop my bars while holding the same hip angle. My torso angle therefore dropped down to 6 degrees. Objectively the experts say that 80% of wind resistance is from our bodies, so the more aero we can become, the greater the ROI. WIth a round ring in this same position I had a significant drop in watts because my hip angle became too small and couldn't generate power. For me it was a no brainer of a switch and I'll likely never go back to round rings.

Pretty sure Coach P uses'm too.

William Jenks

Sukhi - you raise a really interesting point (about geometry). It goes along with the idea of using shorter cranks.

Can you tell us what the difference (in mm) is between the long axis and short axis of the rotor chain rings is? Could be the whole reason for increased power!

Pina

Ahh I realize I missed 1 crucial point above... Yes William, when I went through that geometry "make over" I also dropped down to a 170mm crank. So that must be factored into the equation with what I've written above. That drop in crank length played a crucial role too.

I measured 10.9cm long axis and 9.9cm short axis on the large rotor compact chain ring. So the difference is approximately 1cm (sorry I'm canadian, metric... ; )
As I reread what I've written it's clear the crank length allowed me to drop my front end while I feel the chain ring allowed me to hold watts as it changed the amount of force I required to generate at 12/6 o'clock (which I couldn't hold with a round chain ring).

Interesting discussion.

William Jenks

OK, realized looking at this again that your chain rings might be elliptical but the crank arms still go in a circular motion of course. What was I thinking? But anyway, it does make sense that the shorter crank arms would do that for you.

Coach Patrick

I have shorter cranks and Jennifer I recommend you check those out first before elliptical rings. I do use them (as of August this year) and really enjoy them...for me I have found they eliminate any perceived dead spot in my pedal stroke due to aero position...just nice and smooth with resistance at just the right points. Again, very hard to say given the great data above, but I have enjoyed adding them to my TT arsenal. (that said, I think moving from 172.5 to 170mm cranks was a real gain for me)

Al Truscott

I guess I could easily find this out the way I learn most things these days, from a Google search, but ...

If I want to use elliptical chain rings, do I need to get a new crank (spider) or can I fit them on my SRAM Red which I just bought this year?

John Withrow

@Al-- You can put them on your existing crank, just make sure you get the right bolt pattern. usually 110 for compact and 130 for standard. I think I'm going to try the Osymetric ones, just gonna wait to get a set cheap on eBay... I use an SRM and will need to send it in to be re-callibrated once I put them on.

Pina

If you're ever up for a power meter upgrade look into power2max.ca
No calibration required, as accurate as the srm gold standard, (supposedly). More affordable too. Love mine

John Withrow

I just pulled the trigger on a set of Osymetric chain rings last night... I'll let you know what I think of them once I get them all setup. It will be the "only" thing I am changing, so maybe I'll try to get myself back to a "steady state" as far as my biking fitness goes before I put them on and see if either my seat of the pants or my powermeter

Satish Punna

Posted By Sukhi Muker on 29 Nov 2012 04:46 PM

If you're ever up for a power meter upgrade look into power2max.ca

No calibration required, as accurate as the srm gold standard, (supposedly). More affordable too. Love mine

 

Do you know how I tell what BB I have and if they will fit?

John Withrow

Satish-- What kind of bike do you have? Brand/Model/Yr For Example: Cervelo/P3/2009

Going to the company's website to look at the spec of the bike should tell you what BB you have. Or just put it in here and one of us gear heads will know...

Satish Punna

Posted By John Withrow on 30 Nov 2012 08:31 AM

Satish-- What kind of bike do you have? Brand/Model/Yr For Example: Cervelo/P3/2009



Going to the company's website to look at the spec of the bike should tell you what BB you have. Or just put it in here and one of us gear heads will know...

 

Thanks for your help.  I have an argon-18 e-112 2012 model (white and black).  Apparently these were available with multiple bottom brackets (not sure).

John Withrow

Satish, That's a sweet bike! It looks like the 2013 version has a BB86 bottom bracket. But it looks like the 2012 Argon-18 e-112 has a generic English thread bottom bracket so I think you would be fine to throw in a simple GXP adapter and use something like the SRAM S900. What crankset do you currently have? If you have to buy a new cranset along with that Power2Max powermeter, it's not obvious to me that it's all that cheaper than a Quarq.

There's another new (less expensive) entrant in the market as of January: http://www.dcrainmaker.com/2012/09/stageone-699-ant-bluetooth-smart-crank.html http://store.nexternal.com/stages/all-stages-power-meters-c2.aspx But I'm pretty sure Coach Rich will give you a swift kick in the nutz if you buy a first generation Powermeter...

Pina

@John - Love to know how it goes with the Osymetric

Satish Punna

 Thanks! I'll take it under consideration.  I have a powertap training wheel i switch between my tri and road bikes, but I need (want) a rear aero race wheel and am weighing the options of getting another wheel with a PT hub, or just going for the crank based PM and a wheel (more expensive I know, but hopefully less so in the longer run).

Pina

@John & @Satish
FYI: Rotor 3D crank, standard chain rings with Quarq $2166
same set up with power2max, but the cooler looking aero oval rings $1549, save over $600 for a better set up, the math is still fresh in my mind...

tim cronk

I have em. I like em. I have 165mm crank rotor3d Q-rings compact Quarq set up. Having said that, I think its sugar water. When I get on my old bike with 172.5 cranks, standard gearing , and round rings , I am just as fast or slow however you look at it. I really dont feel any difference nor does the data show any difference. Would I buy em again? Probably wouldnt. But certainly going to keep the ones I have on my bike.

Pina

Just spoke to Michael @ Power2Max and he's pumped to set up an EN team discount. Patrick has given the thumbs up too. Just introduced them so it will be available in the hause soon.

Peter Wick

Okay, Patrick. Here's my question for you regarding the Q-rings. The manual says you need to start with them at position 3 (3 dots over the bolt hole) and get used to them before trying other positions. I've found that on my road bike I like either position 2 or 3 and I ride in a particularly hilly area, regularly needing to get over 12-15% grades on regular rides and do hill workouts on some of the local 20%+ hills. I didn't do much fussing with them on my tri bike and am even considering going back to round rings because of shifting issues. I kept throwing the chain and it was very hard to get the front derailleur set up well on my Speed Concept.

Rider posture on a tri bike is different and the way the muscles are stressed are different depending on which setting (1 through 5) you have the Q-rings set up for so is there a consensus on the best configuration of these things for triathlon? Does it still come down to rider preference or has anyone found a pattern that would indicate better or worse choices? I suppose time trialists have weighed in on this but those folks don't have to hop off the bike and run so I don't know if their input would be helpful. I haven't had time to do the research myself so I'm asking here.

Pina

@Peter A lot depends on seat angle. I have a 76 degree angle, pretty aggressive and I'm at position 5. I generate the most consistent power here. This was set up by my bike fitter.

Gene

i have had this position question floating around my head for a while.  I ride a very steep position, effective 80-82*.  Since I got the q rungs in august I have been ridding in OCP 3. I have a compact Quarq so unfortunately I am limited to OCP 3.  Bummer.  But I have my eyes peeled for an Aero 110 50 or 52.  I will machine out just the minimum clearence so I can test with OCP 4, and 5.  It is not going to be a cheap experiment.