Rotor Q-Rings QCarbon 4bcd Outer Chainring - for Shimano

Lighter, stiffer, more aero. Rotor’s Qarbon Q-Rings for Shimano four-arm cranks are similar to their standard oval-shaped road chainrings, only better in every way. Rotor came up with an idea. Their engineers wanted to get more power from their legs to drive the rear wheel. They figured that rather than training the legs to work around dead spots in the pedal stroke, which is what people do with round chainrings, they could add power by changing the shape of the chainring to work with the most powerful spots. That was the spark that developed the Rotor Q-Rings. Rotor’s Q-Rings are oval, with what they refer to as 10% ovality. That means their 53-tooth outer ring varies its leverage, from being a virtual 51-tooth chainring at the dead spot, to a virtual 55-tooth ring at the most powerful moment of your stroke. This way, your legs can get through the dead spots faster and then have more power when pushing down at the sweet spot of the stroke. These Qarbon rings are 20% stiffer and 8% lighter than their standard rings. they start with a CNC-machined aluminum skeleton and then add 3K carbon to fill in the holes and add rigidity. There are four sizes: 54- 53-, 52-, and 50-tooth. They have three adjustment points (four for the 50)  that allow you to fine tune your power. A user manual is included so you can install and adjust properly. This other ring will fit on most 100mm bolt circle diameter five-arm road cranks. Power meters from Quarq and SRM have stuff that interferes with position, so in these cases, Rotor recommends their standard Q-Rings. This outer ring will fit on most Shimano four-arm cranks. The one exception is the Dura-Ace 9100. As the standard Shimano outer ring is threaded, you’ll need to supply chainring bolts when you switch to this Rotor chainring.