Did anyone see this oval shaped chainring on one of the CSC riders today at the Tour of California? I cannot recal who was using it, but they mentioned it while he was riding. They claim it gets rid of the dead spots on your pedal stroke. Comments?
oliptical chainring?
- Thread starter rudycyclist
- Start date
Bobby Julich's O.symetric elliptical rings:
see this for more details:
julich's o.symetric rings
osymetric rings
see this for more details:
julich's o.symetric rings
osymetric rings
Just for reference, I looked up how much one of these would be directly from osymetric. The price in Euros was 200. American dollars was about $250 for the chainrings!
O Symetrics have been in use by CSC for 2 seasons now. Even Phonak used oval rings altho not from the same manufacturer. Other oval rings available are Rotors Q Rings popular among triathletes/MTBers/Cyclocrossers.rudycyclist said:
http://www.rotorcranksusa.com/reviews.shtml
Elliptical chainrings are something that seem to resurface every few years in cycling in one form or another. Always with the claim that they "remove the dead spot" in the pedal stroke. There was a time back in the 80's (I think) when you literally couldn't buy a Shimano crankset that didn't have their patented "Biopace" elliptical chainrings. There are folks out there that swear by them. A lot of people, especially professional cyclists, seem to eschew them because they claim that they disrupt their smooth, circular pedaling cadence. It's really nothing new. They come and go. They'll probably disappear and then resurface again in five years or so.
Rotors are popular with recumbent riders as well.
Also the current crop of non-round chainrings is somewhat different from Biopace--in that with Biopace, the "tallest" diameter of the ring was aligned with the crankarms (on an upright bike). This was supposed to decrease the "dead spot" but put higher stress on the knee at the top of the pedal stroke, when it was bent the most.... Often with the rings we are seeing now, the "tallest" part of the ring is set roughly 90-degrees from the crankarms. The reason is that this is said to let your cranks speed up during the middle of the power stroke, but "slow down" near the end of it. It's supposed to lower stress on your knees.
Rotors are around $250 for a triple road set; sme of the smaller shops are charging way more than that. There's at least one that will let you submit a shape as a CAD file and they'll make it for you. ....I just with Rotor made a middle road ring that was 42T, their largest is 40. :/
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Also the current crop of non-round chainrings is somewhat different from Biopace--in that with Biopace, the "tallest" diameter of the ring was aligned with the crankarms (on an upright bike). This was supposed to decrease the "dead spot" but put higher stress on the knee at the top of the pedal stroke, when it was bent the most.... Often with the rings we are seeing now, the "tallest" part of the ring is set roughly 90-degrees from the crankarms. The reason is that this is said to let your cranks speed up during the middle of the power stroke, but "slow down" near the end of it. It's supposed to lower stress on your knees.
Rotors are around $250 for a triple road set; sme of the smaller shops are charging way more than that. There's at least one that will let you submit a shape as a CAD file and they'll make it for you. ....I just with Rotor made a middle road ring that was 42T, their largest is 40. :/
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I am thinking about getting one before road nats. I figured I'll need every bit of power my bike can push out
i recently purchased a Q-ring and i like it. now, it didnt turn me into a superman overnight, but i noticed an instant 3-5W improvement on my LT intervals, plus my legs didnt burn as much. im not going into any scientific testing, simply relaying my personal experience. when im cruising around in L2, the wattage increase is about the same. i would push 155W comfortably for 3.5 hours at the most. but then after the q-ring upgrade, i was pushing MINIMUM 155W and frequently 160W (and at a lower heart rate). if you have the cash, and you want the extra power then get the upgrade.
I have 2 questions for the post above:
1) Did you put the ring on your TT setup or just on your normal road setup?
2) Was it hard or difficult to install? The reason I ask is because I noticed the rings are setup at an angle. Did they tell you to put the ring at a certain angle or degree according to your crankarm?
Also, I'm a junior and am wondering if the rollout would be the same with an elliptical ring (52t) from Rotor? (Remember us juniors have gear restrictions)
1) Did you put the ring on your TT setup or just on your normal road setup?
2) Was it hard or difficult to install? The reason I ask is because I noticed the rings are setup at an angle. Did they tell you to put the ring at a certain angle or degree according to your crankarm?
Also, I'm a junior and am wondering if the rollout would be the same with an elliptical ring (52t) from Rotor? (Remember us juniors have gear restrictions
)
Ummm,,,, the reason recumbent riders like them is because they do help to spin fast.nyracer said:
Although I have not tried them myself.
Yet.
I think the Q-rings are rather expensive for what they are, but recumbent riders who try them generally do give positive reports.
And BioPace rings were trapezoidal, if I remember right. Trapezoidal rings have fallen out of favor because they often won't shift well. ...There's also elliptical, asymmetrical and epicycloidal chainrings as well (the ideal shape is a matter of debate).
The Rotor 52T would have the same rollout as any other 52T ring; the circumference is the same, it is just the radius that varies. That's no guarantee they're allowed however. Might want to ask ahead, or maybe pack your old-fashioned rings along just to be sure.
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Okay, here's a caveat that you may want to give great consideration to (I'm basing this on a vintage 52t SUGINO elliptical chainring that have which dates from the prior eras whose shape is mimicked by the Q-Rotor rings BUT which only had ONE mounting orientation) -- without putting the ellipitical ring back-to-back with other rings, I would say the OD varies between what you would have on a 56t & 48t ... you'll probably want/need to change the front derailleur to a TRIPLE type so that the rear (trailing edge) of the cage doesn't interfere with the chain.rudycyclist said:I am thinking about getting one before road nats. I figured I'll need every bit of power my bike can push out
ALSO, because of the relative OD at the extreme, you will probably need a longer BB spindle to ensure that the ring clears your chainstay BEFORE you even try mounting the rings UNLESS you don't mind gouging the chainstay!
... the longer spindle will affect the chainline which may or may not be a consideration ... and, definitely affect the pedal's Q-factor (which can be adjusted somewhat by moving your cleats, or NOT depending on where they currently are mounted on your shoes).
If you are currently using a two-piece crank with external bearings, well, you MAY have to buy a NEW crank which is triple capable to get the longer spindle ... maybe, not. It depends on the current clearance your chainstays & chainwheels (probably NOT a problem if your frame has 650c wheels).
You don't need, but it is advised that the shape of your inner ring matches (not quite as great a problem as with the old Shimano Bio-Pace, but shifting is otherwise dodgy) OTHERWISE shifting could be really ugly.
Buying the Q-Rotor rings is not only a big financial investment, but also one that may be disappointing if you don't take into account the provisos I've outlined to ensure the rings fit on your bike's frame...
If you wwant to get rid of the deadspot, it would be better to (if you have the cash) invest in Power cranks. Hard at first but alot of people swear by them. They are more expensive than oliptical chainrings but in the long run your going to be a much better rider if you keep at it.
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