Rotor???s 3D24 Steel Road Crank is Rotor???s technology in an affordable and most easily adaptable package. It shares most design traits with other Rotor cranks, but it???s the originator of the tech, it is at a much nicer price, and a tiny weight penalty: the 175mm arms with 130mm bolt circle diameter spider is eight grams heavier than the 3D30 version, 540g vs. 532g.
This crank will work with just about all modern bottom bracket standards, meaning that whatever bike you have today, whatever bike you might want tomorrow, you can use this crank, so long as you get the proper Rotor bottom bracket and install the proper spacers, which come with the crank.
The crank is light thanks to several factors. First is the 24mm steel bottom bracket. This is the diameter Shimano pioneered with their thru-axle cranks. Second is the choice of drilling and milling the arms to remove excess weight. The interior possesses Rotor???s Trinity Drilling System, which means that each arm has three hollow channels running the length of the arm. The material and shape make the arms stiff, and the careful drilling makes them light.
As mentioned earlier, this crank works with any bottom bracket. Rotor calls it the UBB, Universal Bottom Bracket, System. Rotor has designed their own BB???s, which allow you to install this crank on English-threaded, Italian-threaded, BB30, PF30, BBright, BB386EVO, and BB86 bottom brackets. If you get this one crank, you can move it from bike to bike without regard to the standard the frame employs
The spider is a five-arm design, available in either 110 or 130mm bolt circle diameter (aka compact and standard). Obviously, these spiders will fit Rotor Q, QXL, and NoQ chainrings. They should also fit appropriately-sized 9/10/11-speed rings from their competitors.
The thru-axle is attached to the drive-side arm, and the system is secured by the non-drive arm. They use their Double Thread Technology pinch bolt on the left arm. The dual threading means that both sides are threaded and the ??neutral??position is actually closed, not open, which means the bolt and arm get less stress than if it were manufactured in the open position. Use the pre-load bolt to remove play, then tighten down the pinch bolt to spec, and it???s set to go.
The Rotor 3D24 Road Crank comes with the fixing bolt and all the spacers necessary to get this crank onto any of the bottom bracket standards it is designed to work with.