Road Cycling - Flex- carbon vs steel

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Patriot
08-17-04, 12:28 PM
Quick question...

Is a halfway decent carbon frame stiffer than a steel frame? Does the carbon provide more efficient power transfer through the crank? Or are they way more flexible than steel?

Patriot

Moonshot
08-17-04, 12:52 PM
Trek tells you their OCLV frames are as stiff as their steel frames (equally efficient power transfer). They also claim the OCLV bikes have a greater fatigue strength, making them last longer than their steel bikes.
Moonshot
08-17-04, 12:54 PM
I say my Trek OCLV is more "flexy" in the bottom bracket than my Bianchi steel bike.

Tree Trunk
08-17-04, 12:55 PM
After riding a Trek 2300 (carbon + aluminum) for the last eight years, I rode a steel Bianchi for 78 miles this past weekend. The steel bike felt faster and I don't remember feeling the steel flex when I really cranked.
55/Rad
08-17-04, 12:59 PM
My Lemond steel is stiffer than my carbon Trek 5500 though not by a great margin. It's also a smaller frame - 55 vs. 58. That said, I have never noticed that the Trek wasn't stiff enough or inefficient in the power transfer through the crank.

Both are amazing rides, though different.

55/Rad
Patriot
08-17-04, 01:36 PM
The reason I ask is because I have an older Tange #1 cro-mo frame, and when I really power stroke up a hill, I flex the crankcase to the point where the chainring rubs the chain up against the front derailer side to side.

Will a carbon frame do this?

Patriot
Moonshot
08-17-04, 02:27 PM
The reason I ask is because I have an older Tange #1 cro-mo frame, and when I really power stroke up a hill, I flex the crankcase to the point where the chainring rubs the chain up against the front derailer side to side.

Will a carbon frame do this?

Patriot

I would guess it's flex in your crankset that's causing this. This happens with my 7400 Dura Ace also. I think it happens with most all cranksets. However, Bicycling magazine commented that the 7800 Dura Ace crankset did not exhibit this common behavior.
MERTON
08-17-04, 02:48 PM
crap. that happens even on my mtb... and i really do not pedal that hard.

if you're really worried about this you could always get a custome steel frame or get a cervelo super prodigy frame. i think steel ends up being the stiffest in the end, if it's used right.