# centaur / athena / chours Carbon Crank Difference



## Thad Matthews (Aug 3, 2007)

This is general question about the difference between campy's various carbon cranks (crank arms only). As I understand it record and super record have hollow arms. So what is the difference between:
1. Chours and record
2. Chorus and Centaur/Athena

Also, is there a difference between Centaur and Athena carbon cranks, other than the chainrings?

My LBS seems to think that you can feel the difference in stiffness between Centaur and Chorus and Record. Can you tell the difference when riding?


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## AlexRandall (Nov 29, 2008)

1. Chorus has solid crankarms, record and SR have hollow arms (40g weight difference). The profile of the crankarms are different too. Record seem to be thinner looking from above.

2. Chorus has alloy chainring bolts, centaur has/had steel. The profile of the rings was different too. The large ring on Centaur was much more bulky, I'm assuming to make up for being an inferior strength alloy. Not massive weight differences, and the arms were the same.

Some people can say they feel the difference, most couldn't tell. Its usually completely lacking in objectivity as you may ride one crankset on a day when you're stomping every climb, and the other when you're creeping. Rest assured they are all v.stiff. A lot of tests from german labs and one in RIDE cycling review came up with the heavier or slightly lower-end cranks being the stiffer. Ultegra was stiffer than Dura-ace in the RIDE test.


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## waterford853 (Oct 12, 2008)

I just figured out that the rings on the Centaur (and lower groups) are thinner than higher groups so they are not interchangable with groups that use the machined rings. I tried. 2.7mm vs 3.5mm. This may only be a factor for the large ring, but I have not confirmed.


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## ericjacobsen3 (Apr 27, 2007)

Centaur rings are thinner because they are stamped but the stamping creates some dish to more or less make up for the different thickness. 

While slumming in the Mirage group, I switched from 9 or 10 speed Mirage stamped rings to 8 speed 1/10 of a bolt circle rotated Record rings with no problem. Now what could get tricky with such a switch is 9 and 10 speed Record big rings are machined thinner at the bolts. I have also seen the arm tabs between the rings can vary. 

In general I would expect matching rings of the intended speed to work if moved to a different crank. As long as your arm tabs are the same thickness between cranks, rings should work if switched.


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## ericjacobsen3 (Apr 27, 2007)

Oops, my case was a move from a 4 arm crank to a 5 arm and it works aside from the wrong side recess on one hole of the big ring.

If you use a different spacer for the bolt against the arm, you might make it work.

Definitely a proceed with caution case if you are investing big bucks in new rings. Of course if you are doing that you are likely better off to ebay that sucker out and get a 10 or 11-speed Chorus crank. Life is too short for stamped rings. They actually worked OK to me but it is a crime to put on the beautiful carbon crank. At least Athena has machined arms.


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