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Lighter weight? Check. Higher stiffness? Check. Carbon fiber? Check. Rotor is hitting all the boxes with its latest crank arm release, a carbon fiber version of the modular ALDHU cranks, which improve on the aluminum version in every way, including increased modular crankset customization.
The first generation alloy ALDHU crank arms were not exactly heavy to begin with, weighing about 600 grams for some crankset combinations when fully built, but there is always room to improve, and the new carbon version brings quite a weight savings. ROTOR says the new carbon arms shave 100 grams, coming in at 260 grams for a size 172.5mm. Built up with 50/34 compact chainrings, the crankset totals out to just 523.5 grams.
That weight savings alone will give many cyclists reason to upgrade. But ROTOR gives another reason by increasing stiffness as well. Vertical stiffness has increased by 11 percent, while horizontal stiffness has increased by 36.1 percent. It’s all thanks to something ROTOR calls Twin Leg Technology. The carbon crank arms have a patented fit interface with the axle that, along with the axle’s robustness, leads to increased power transfer when force is applied to the left crank.
A Family of Options
With the ability to choose chainrings, spider or even axle size, there’s likely an ALDHU crankset option that works for your needs. There are aero or standard spider options, as well as power meter options for both types. There are standard, light and aero chainrings available. And there are 1x or 2x options as well. If you prefer a larger Q-factor, then choose the offset axle instead of the standard axle, which increases the Q-Factor from 147mm to 152mm. The modularity of the system even allows for adjustment of the orientation of ROTOR’s oval Q RINGS chainrings for a precision setup.
Specs and Details
Price: $449 for arms; $509 for cranks/spindle
Crank arm weight: 260g (size 172.5mm)
Crank arm length: 165mm, 170mm, 172.5mm, 175mm
Axle length: 30mm, standard and offset versions available
Available February 2021
More info: rotorbike.com