SRM SRM PowerMeter Rotor 3D+ $3,695.00
Rotor with power.
While Rotor burst onto the cycling scene through the effectiveness of its Q-Rings, the developers still recognized that there are those of us who prefer to stick with standard chainrings. This is why the Rotor 3D+ Road Crankset is also fully-compatible with round chainrings. Now, your options have once again increased with Rotor, as its developers have partnered with the king of power, SRM, in order to create the new SRM PowerMeter Rotor 3D+ crankset. By combining the pinpoint measurement accuracy that SRM is lauded for with Rotor's lightweight rigidity, the SRM PowerMeter Rotor 3D+ will satisfy the needs for anyone seeking the ultimate in power training.
The 3D+ crankset is compatible with any BB30 or standard bottom bracket frame. And in terms of construction, the crankset features a CNC-machined alloy that uses Rotor's Trinity Drilling System in order to create three holes drilled end-to-end. Due to the larger axle-crank contact area of a BB30 crank, all three holes are able to be drilled from the axle side of the crank arm. This allows for further optimization of wall thicknesses, while also improving both the weight and the weight-to-stiffness ratio of the crank arm. The 3D design also allows Rotor to remove any unnecessary material from the core, without compromising the crank's strength or stiffness.
As with any SRM deisgn, the goal of this pairing was to combine the stiff weight saving attributes of the CNC-machined alloy crank with an accurate wireless power recording system, only without scaling back the adored quality of either device. This is easier said than done. However, SRM pulled this off by leaving the crankarms unaltered, CNC machining a new rigid spider, and improving the design of the meter's strain gauges. The eight strain gauges for the PowerMeter are a system of sensors that detect any resistance and vary their output when experiencing applied force. The next step is for the strain gauges to convert this data into electrical resistance so that it's able to be measured. The refinements to the system deliver outstanding results. The SRM expresses an accuracy of +/- 2.0% between 30 and 255 rpm with a wattage range between 0 and 4096 watts. Compared to the new G3 PowerTap that has the same range of accuracy, but only between 40 and 130 rpm, the SRM PowerMeter has nearly doubled the system accuracy of its greatest competitor while shaving grams in the process. You're also able to expect a weight savings over other power measurement systems, as the SRM PowerMeter Rotor 3D+ weighs in around an alarmingly low 839g with cranks, PowerMeter, and chainrings. SRM also extended the battery life of the Rotor 3D+ PowerMeter to roughly 1400 hours, and it provides a three-year manufacturer's warranty.
The 3D cranks have a precise bearing preload adjustment due to the design of the compression ring. To provide a comfortable duration in the saddle, the SRM PowerMeter Rotor 3D+ provides a wide-stance U and Q factors of 147mm. It is available in crankarm lengths of 170mm, 172.5mm, and 175mm, and in both standard and compact configurations. For both options, the chainrings are available in both Shimano/SRAM 10-speed, and Campagnolo 11-speed, compatibilities. The PowerMeter operates wirelessly with ANT+ Sport, and is being offered as a standalone item. However, it is compatible with PowerControl 7 and PowerControl VI.
The SRM PowerMeter Rotor 3D+ is also compatible with BB30 frames (68mm BB width), Cervelo BB right specification, and classic threaded frames, using Rotor 'BSA30' BB cups.