Rotor Components, following ten years of development work on their Rotor cranks, wanted to make available to bicyclists a way to experience the energy-saving advantages of their cranks, but at lesser cost and with the use of existing crank arms, so they designed the Q-Ring concept chainrings. After studying other maker’s attempts at an oval chainring, Rotor felt that analysis of the dynamics of pedaling indicated that the ovaling of the previous attempts was positioned in the wrong portion of the pedal stroke. Maximum force and leg extension fell further into the pedal stroke than the previous company’s chainrings position of the lobes. Also, Rotor’s engineers felt that Bio-Pace and the other manufacturers didn’t allow adjustment of where this increase in effective diameter was to commence. Rotor remedied this by offering continuous (130 bcd) mounting holes—OCP (optimum chainring position), around the bolt circle, on each ring so that a rider could advance or retard the timing of the increase in leverage to fit his own pedaling style. Rotor’s website has a very detailed explanation of how to tell which mounting positions may work best for your riding style. The Rotor designers also discovered through testing that by decreasing the  diameter of the sprocket in the dead zone at the top and bottom of the stroke—a 53-tooth chainring is an effective 51-tooth through the upper and lower dead spot of the pedal circle, increasing to an effective 56 in the zone of the circle where most power is generated—also generates less lactates, due to increase of speed through the dead zones.

TECH
Rotor’s Q-Rings are intricately CNC-machined out of aluminum and then shot peened, after which nickel plating is then used for its strength and long wearing characteristics, while shifting pins and ramps are incorporated, along with a stepped teeth design to enhance shifting. OCP (Optimum Chainring Position) bolt timing holes are machined extremely close together, the entire circumference of the bolt pattern circle (130 bcd) and five different positions are indexed for easy customization to your own pedaling style. Q-Rings come in Road 130- and 110-bolt circle (Shimano compatible), for double or triple cranks, and Road 135 (Campagnolo compatible) bolt circle diameter. Check with your dealer to be sure that your crank arms will accept the rings. Certain cranks may have an interference issue with one (or both) rings due to reinforcement ridges formed on the inside of the crank arms. Our 53/40 (130 pattern) had a claimed weight of 153 grams.

RBA SAYS
Sure, we remember Bio-Pace (and Bio-Pace 2, for that matter), but Q-Rings are different, right? Well, in fact they are. Rotor Components has taken a hard look at how we pedal, and where we make the most power during each stroke. They’ve also considered the velocity of our stroke and where, during the pedaling circle, it is the greatest. From their measurements, these two factors reach their peak as we reach approximately 2 o’clock, following through to approximately 5 o’clock in the stroke. But here is a major point of difference from Bio-Pace; instead of being told that this is where we must mount and use the chainring, Rotor Q-Rings have completely encircled the chainrings with timing holes, so that the rider can position the ring where he is most comfortable. So do they work? We found that we were able to climb using at least one click higher than with round rings. Also, to our amazement, lactic acid buildup was not as prevalent as in the past. Standing is very effective because of the decrease in time that your pedals are in the less powerful position moving your legs through the dead spots faster and back to position that your stroke is more effective. We’ve been using the number 3 position which is where Rotor suggests you start, but are experimenting with the small ring in the number 2 position for climbing. When we stood, it moved our hips in front of the bottom bracket, which changed the relationship with the lobes on the rings and we felt more powerful and in control than when using round rings. We feel that Tri-athletes and time-trialists could gain some advantage with Q-Rings, and most riders would as well, unless they have an extremely well developed spin. During an all-out sprint, however, you’ll notice a bit of unevenness in your pedal stoke, but we’re talking 130 cadence or above and Tom Boonen just off of your rear tire, not plodding along. Matter of fact, we’d be a little uneven with round rings in that particular situation. Shifting was very good, and it only took a few miles to get used to the new feel. We liked them, but recognize that this is rocking the very foundation of cycling. It’s up to you to decide if you’re going to give them a try. In the meantime we’re trying to scam a set for our 110 bcd setup.

Price: $159
Info: www.rotorcrankusa.com