More innovation from ROTOR - eliptical chainrings
By Mike Hanlon
August 19, 2005
August 20, 2005 We’ve written about ROTOR bicycle crank systems before – the ROTOR crank makes infinite sense in that it reduces the power "dead spot" at top-dead-centre (TDC), reduces stress on the knees and offers the ability to get more power to the rear wheel. (see simulation) ROTOR is now working on a new project … elliptical chainrings with variable regulations that can be customised for each rider's needs. The ROTOR Q-Ring is different from other ovalized chainrings; a new concept incorporating a patented variable regulation system (OCP) that applies some of the biomechanics of the Rotor Crank System to conventional cranks. Q-Rings give you more power during the pedal down stroke, just after the moment you develop maximum power, when you are generating 90% of your power output. Feedback from Q-Ring test pilots has been unanimous: easier and faster pedalling at high cadences, faster times in time trials (flat or rolling courses), much faster when climbing, a significant reduction in knee discomfort and a lower heart rate while achieving the same speed that they did with round chainrings on conventional cranks.
OCP (Optimum Chainring Position) is a Rotor patented feature is the secret to success, where others have failed. The patented OCP System allows you to choose the angle where you obtain the maximum gear ratio, customising pedalling to each and every cyclist, where you need it most. Since the maximum power moment is different for every cyclist (performance is different depending on pedalling style and position on the bike), the OCP System customises the Q-Rings to your body geometry, bike geometry and cycling habits, and to take the maximum advantage of alternative leg inertias on every pedal rotation. OCP is Q-Ring's bio-mechanical key!
Other claimed advantages of the system include:
- It’s easier to pedal at high cadences when power requirements are higher.
It offers better power delivery due to the modulation of the gear ratio every moment. It’s reportedly good on the flats and rolling terrain, and even better when climbing.
It mitigates knee pain: Since Q-Rings demand less requirements of muscular forces in the upper dead-spot, the knee-joints are punished less than when using conventional cranks with round chainrings. Q-Rings minimize the variation of muscle requirements at the dead- spots which mitigates knee soreness. You may want to use the Q-Rings to reduce impact and damage to your knees instead of "pushing" your performance.
Quick adaptation: Q-Rings are designed to obtain a soft, comfortable way of pedaling with uniform muscular work, so they allow an easy and quick adaptation. Q-Rings give a smoother power transfer, maintaining traction on slippery surfaces, and avoiding the bobbing effect on suspension bikes.
How does Q work?
ROTOR Q-Rings do not eliminate the dead-spot (as do Rotor Cranks) but reduce its negative effects, moving the legs faster through the dead-spot and enabling the legs to obtain more strength on the power stroke. Q-Rings change the equivalent tooth size by increasing it when the rider is in the power mode (when more power is available at the pedal down stroke) and decreasing it through the dead-spots.
A 53T Q-Ring, at the upper dead-spot is equivalent to a 51T, but as the pedal goes down and more strength is applied (just passed the maximum power moment), the equivalent chainring tooth size reaches 56T.
About the Q-technology
Unlike the necessity of fitting entirely new cranks as required by the ROTOR system (not such a big deal mechanically but a costly exercise), Q-Rings are user friendly, far easier to install, quite easy to find and change the regulation setting through the patented OCP System and prices are more within the reach of the average cyclist.
Q-Rings are available in the following versions:
Road 53/40T for Shimano and other cranks using the 130 BCD (bolt pattern). Road 53/41T for Campagnolo and other cranks using the 135 BCD. Road 50/36 for FSA and other Compact cranks using the 110 BCD. MTB 44/34/24T for MTB cranks (XT and similar), 104/64 BCD. Other Q-Ring sizes will become available in the future)
Q-Rings will be presented worldwide to the cycling community at the main 2005 international Bicycle Shows:
- EUROBIKE-Friedrichshafen, (Germany) 1st-4th September
EICMA-Milan, (Italy) 16th-19th September:
FESTIBIKE - Madrid, (Spain) 23rd - 25th September
INTERBIKE - Las Vegas, (USA) 26th - 30th September
BIKE MOTION - Utrecht (Holland) 21st - 25th October