Q-Rings are ovalized, but dont confuse them with previous attempts at chainring ovalization! ROTOR Q-Rings were designed to emulate the gear variations of Rotor cranks in the power stroke. They do not eliminate dead spots as do ROTOR Cranks, but reduce their negative effects by moving the legs through these zones faster, enabling the cyclist to generate more strength in the power stroke (where 90% + of all power is produced).
Q-Rings vary the equivalent tooth size, increasing it when the rider is in the power zone. Gathering all experience built up with ROTOR Cranks, we then subtly and smoothly minimized the gear of Q-Rings around the dead spots. Q-rings are better for your knee than standard chainrings because the forces required to keep the bike moving when your pedals are around the upper dead spot are lowered, meaning that tendons and knee joint are not punished as hard. For example, a 53T Q-Ring is equivalent to a 51T near the upper dead spot. As as the pedal descends and more strength can be applied, the equivalent chainring diameter gradually increases to 56T at the moment of maximum power. It then smoothly and gradually returns to a 51 tooth so that the pedals can pass through the next power stroke effortlessly. What really sets Q-Rings apart, is that they also take leg and bike inertia into account, visible in the orientation of the smallest and largest effective chainring diameters.
The vast majority of a cyclists power is produced in the downstroke of the pedal cycle, even for highly trained professional cyclists who slide their feet backwards like the 'mere mortals' can't. This is made very clear in the graph to the left from Ed. Burke's 'Science of Cycling'. This graph is the same for every type of chainring, but how the chainring uses the available leg strength varies vastly. Q rings allow for the leg to pass through the weakest section of the cycle faster, so that they can spend more time in the power zones. This results in a higher power poutput, but more importantly, a reduction in lactates due to reduced strain on the legs around the upper Dead point, which least to a significant reduction in lactates in your muscles, and a resultant increase in endurance.
The orientation of Q-Rings is new to the cycling world, and is one of the aspects that makes them feel so natural. We have taken inertia, leg strength, pedalling speed into account in defining this orientation. Add to this effective central orientation the patented narrow variance OCP (Optimum Chainring Position) regulation system, and you have a product never seen before. Why OCP? Everyone has a different riding style, and a differenty pedalling syle. If a chainring is good for your buddy, it may be awful for you. The real breakthrough for each and every cyclist here is the OCP. You need to be able to rotate the chainrings slightly depending on your riding position and style for them to work best for you.
Ovalized chainring design issues Designing the perfect ovalized chainring is not easy. In fact, its darn hard. Many others have tried before and haven't attained the success they hoped, the reasons of which we will address a little further down on this page. Due the lack of success of past systems, many people have written the idea of chainring ovalization off completely
We at ROTOR disagree with the Idea that ovalisation will never work. Remember, most people thought badly of clipless pedals before 1980. It took many attempts over more than 100 years to find the right formula to let clipless systems take off! The story of mountainbike suspension is shorter but similar.
We know that chainring ovalization can and will improve a cyclist's performance when done properly. So, how can we at rotor think that we have a product that will change the market, when others products were less than successful?
To explain this properly, we need to dive into the process of designing an ovalised chainring. Its not just as easy as squeezing the chainring in a workbench clamp to ovalize it, then selling it. To design a successful ovalized chainring, it took some serious thinking. The first thing one must realize when looking at ovalized chainrings, is that there are three main defining factors for a ovoid design:
the Orientation factor,
the Ovalisation factor, and
the Form factor.
The Orientation factor describes the angle between the centreline of the crank arm and the point where the chainring attains it largest effective diameter. This factor is important in that it defines where the pedals are the hardest to push, and where they are the easiest to push. Correct orientation is crucial in the design of a system which is to be used by many different cyclists. Additionally, a chainring can only be optimized for one particular position at a time. When a cyclist stands up or sits down his hip moves forward or backward, and the orientation of the chainring when the rider is at his dead point changes in regards to the cassette. This is because the dead point is dependent on the location of the cyclists hip, and will always be opposite the hip, in regards to the bottom bracket. Additionally, the varying speed at which different cyclist pedal in different situations, brings the aspect of angular acceleration , pedaling forces and momentum into the picture - all of which effect the optimum orientation factor. This is why we saw the need to come up with the fine regulation potential of the OCP system.
The Ovalization factor is a simple ratio between the diameter of the chainring at its smallest and greatest diameters. This defines the maximum extent of speed variation your pedals can pass through during the cycle. A factor of 1 means the chainring is perfectly round, and a factor of 2 would mean the chainring has a large axis that is twice as large as the smallest. This factor is important for a number of reasons. The difference between a chainring ovalisation factor of 1.1 and 1.4, though seemingly small, is very large : for example, a diameter difference of 1.45 is the usual variance between a mountainbike inner and middle ring. When done properly, ovalization has a positive effect on the efficiency of the cyclists spin, contrary to what many conservative cyclists will say. The ovalization factor also defines the compatibility of the ovoid chainring with conventional derailleur systems. As you can see, the ovalisation factor is crucial for the feeling and useability of an ovalized chainring.
The Form factor is the most complicated aspect of chainring design. This describes both the shape and the area of the chainring: Arcs and Ovals, Angles or flat sections. This factor is important for the pedaling dynamics: where is the speed constant and where are the accelerations? How sudden are those accelerations? is the chainring symmetric or assymetric? This attribute, in combination with the orientation factor, is crucial for knee health. The combination this and the Ovalization factor influences drivetrain stability: intelligent design will prevent sudden free chain length growth, eliminating the risks of loosing your chain through tension problems.
In order to be succesful, Q-Rings needed to combine the successful excecution of each of these three design factors into one chainring. Now they are ready to revolutionise cycling.
