Is it hype or is there anything to carbon cranks being lighter and stiffer resulting in better direct applied force and better times over there steel counterparts? I am of the opinion after test riding a bike with the new dura ace cranks that these cranks and bottom bracket are pretty sweet. I am just suspicious (even though I have a carbon bike and love it) that carbon cranks are better then there top of the line counterparts. The point is, are they worth it? Any comments?
Triathlon Forum
Login required to started new threads
Login required to post replies
Re: Dura Ace vs Carbon Cranks [Greg Hartman]
[ In reply to ]
Hi Greg, first of all nearly all metal cranks (including Shimano and Campagnolo) are made of aluminum rather than steel.
Carbon cranks perform about the same as a pre 2004 Dura-Ace crankset. That is to say, they are about equal in stiffness and within about 30 grams in weight. They also cost about the same.
The new 2004 Dura Ace integrated crank/BB system outperforms all the carbon cranks on the market. It is stiffer and lighter than anything else. However it is also pretty expensive and it looks a little funny.
Carbon cranks perform about the same as a pre 2004 Dura-Ace crankset. That is to say, they are about equal in stiffness and within about 30 grams in weight. They also cost about the same.
The new 2004 Dura Ace integrated crank/BB system outperforms all the carbon cranks on the market. It is stiffer and lighter than anything else. However it is also pretty expensive and it looks a little funny.
Re: Dura Ace vs Carbon Cranks [john]
[ In reply to ]
I stand corrected. I am showing my age or am experiencing alzheimers as the bike I had in the 60's came with steel cranks.
I have been told that I could upgrade my old dura ace cranks with the new ones and keep everything 9 speed and it will perform well. I just do not see the need for replacing everyhing at this point as most of the courses I ride are not that steep. I do not want to get this new crank set and find it shifts like crap.
I have been told that I could upgrade my old dura ace cranks with the new ones and keep everything 9 speed and it will perform well. I just do not see the need for replacing everyhing at this point as most of the courses I ride are not that steep. I do not want to get this new crank set and find it shifts like crap.
Re: Dura Ace vs Carbon Cranks [Greg Hartman]
[ In reply to ]
Well, we've done the best testing we could do on a number of cranks. We even hired an engineer to build a test jig to measure deflection of the arms. Our tests are not super-sophisticated, but they are plenty sophisticated enough to reveal major differences. We found differences in stiffness so minor they could barely be measured, even under much greater force than a cyclist could apply.
I will conceed that I do "feel" something different about the Dura-Ace crank/bottom bracket assembly. It seems more "sure footed". However, even the most flexible crank available is likely to be plenty stiff for the strongest Tour de France rider, and complete overkill for you and I.
Also, remember that if the crank was (hypothetically) completely rigid (impossible) the energy would simply be transfered elsewhere where some delay in energy transmission or conversion to some other form energy (heat?) would occur at the proverbial "weakest link in the chain", where ever that may be.
I think the critical aspects of crank performance are not stiffness, since they are all plenty stiff enough. These may be of more pragmatic relevance when evaluating cranks:
1. Stiffness of chainrings and spider for front shifting repeatability.
2. "Q" factor is appropriate to your body dimensions (unfortunately most cranks are within a few millimeters of the same).
3. Cost. Prices vary from very fair (for the excellent and grossly under rated Ritchey cranks) to utterly absurd for some Carbon fiber models.
4. Weight.
5. Your taste in appearance.
Check out our crank article, copy this URL and paste it in your browser:
http://www.bikesportmichigan.com/reviews/crank.shtml
Good luck and Happy New Year!
Tom Demerly
The Tri Shop.com
I will conceed that I do "feel" something different about the Dura-Ace crank/bottom bracket assembly. It seems more "sure footed". However, even the most flexible crank available is likely to be plenty stiff for the strongest Tour de France rider, and complete overkill for you and I.
Also, remember that if the crank was (hypothetically) completely rigid (impossible) the energy would simply be transfered elsewhere where some delay in energy transmission or conversion to some other form energy (heat?) would occur at the proverbial "weakest link in the chain", where ever that may be.
I think the critical aspects of crank performance are not stiffness, since they are all plenty stiff enough. These may be of more pragmatic relevance when evaluating cranks:
1. Stiffness of chainrings and spider for front shifting repeatability.
2. "Q" factor is appropriate to your body dimensions (unfortunately most cranks are within a few millimeters of the same).
3. Cost. Prices vary from very fair (for the excellent and grossly under rated Ritchey cranks) to utterly absurd for some Carbon fiber models.
4. Weight.
5. Your taste in appearance.
Check out our crank article, copy this URL and paste it in your browser:
http://www.bikesportmichigan.com/reviews/crank.shtml
Good luck and Happy New Year!
Tom Demerly
The Tri Shop.com
Re: Dura Ace vs Carbon Cranks [Greg Hartman]
[ In reply to ]
Greg, the new crankset should shift fine with your 9 speed stuff. But I don't recommend the upgrade - it is unlikely you would ever notice the difference and it will probably set you back around $400. Your money would be better spent on doing more races, a power meter, better race wheels, an integrated handlebar, etc.
Re: Dura Ace vs Carbon Cranks [Tom Demerly]
[ In reply to ]
Thanks. I agree with all of you. I just had some christmas money burning a hole in my pocket and since I have a lot of the other toys (wheels, computrainer etc) I thought it might be a good time to upgrade since my cranks are about 4 years old even though I doubt I have in any way wore them out.
http://www.bikepro.com/products/cranks/bullseye.html