Searching the internet for credible tests of carbon vs. aluminum cranks for stiffness is hard to come by. I just find a lot of repeated marketing hype. Does anyone know of any tests where actual stiffness measurements were reported?
My personal experience is that I’ve put a lot of XC miles on both high quality carbon and aluminum cranks. Having broken two carbon cranks at the pedal inserts I’m going back to aluminum now, which I have never broken. This is in regards to durability.
The obvious difference is weight, where my Next SLs (carbon) are about 160 grams lighter than my Turbines (aluminum). Even as a self-confessed weight weenie, I no long care about this weight located low and in the center of the frame if it costs me durability. And the expense wouldn’t bother me if they lasted at least a few years. My carbon cranks failed after six months. I’m concluding that making mtb cranks out of carbon with alloy pedal and crank inserts is a poor design.
I have not been able to feel any difference in stiffness (on FS XC bikes) and I have no reason to believe the marketing hype that more expensive carbon cranks are any stiffer than say a $105 SRAM NX crank. Does anyone know of any credible tests on this topic?
It’s pretty much what you describe. Carbon parts are cool. And light, and pricey. They definitely have their place. But if you’re a strong rider, carbon cranks don’t make a lot of sense. Very little gains, and failure is a real possibility (as you’ve experienced).
I ride (road) with a guy who has tree trunks for legs. Strong rider/racer. He’s snapped carbon chainstays on two bikes so far. Just sayin’.