KCNC K3 Cobweb vs. Extralite Octaramp RC2 vs. ?

Discuss light weight issues concerning road bikes & parts.
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by TexasWillis

I'm looking into changing my chainrings on my FELT and found these two options. Does anyone know if these are worth my time or is there a better set out there? Looks doesn't matter as much as flex and loss of power.

They are both offered at fair wheel bikes' website for a better idea of the two sets I'm talking about.
KCNC K3 Cobweb Road
http://fairwheelbikes.com/kcnc-k3-cobwe ... -4364.html

Extralite Octaramp RC2
http://fairwheelbikes.com/extralite-oct ... -p-31.html

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by Danza

Stronglight CT2s or PraxisWorks seem to be the popular choice around here lately.

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by voodoojar

I have a set of Cobwebs, they seem good to me and are light a little too flashy looking though. I have never been able to feel flex in a chainring. Is chainring stiffness something you can actually measure in terms of power loss and if so do you have some test data to show power loss based on chainring stiffness?

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by madcow

I think both work decent depending on the group you are using, but if what you are after is pure performance then you should also be looking at the Praxis rings.

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by TexasWillis

When I mentioned my choices to a friend he brought up power loss. It seemed reasonable that if flex in your bars would result in lose power. Than flex in your power train would do the same. I'm not a TT'r just a rec. rider with a small group. I do ride in the Texas hill country and the Kansas wind. Those are places I couldn't afford to lose any power. Looking flashy and sharp won't be bad either.

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by Qman

I'm also interested in the Cobwebs and the RC2's. There doesn't seem to be very much information on their relative performance. Hopefully someone else has experience with them?

Regarding flex, it is going to largely affect the performance of the front shifting. More flexible chainrings will deflect during a change up or down. This will slow down the gearchange, and result in less predictable shifting. Rings such as Dura-Ace have been designed for greater stiffness in sideways loading, and that's one reason why Dura-Ace has such good front shifting.

The amount of flex due to pedalling will be very small, regardless of the chainring type. So, I wouldn't worry about power loss with these light-weight chainrings. The main issue is front shifting performance. Also, if you have electronic shifting then stiff chainrings become more important.

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