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Item # RTR0021

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Item # RTR0021


If you've been around mountain bikes for a while, you certainly remember the short-lived fad of BioPace chainrings. And, although the theory behind them is relatively the same, the Rotor MTB Double Q-Ring Set 110x74 BCD is an entirely different beast. These elliptical chainrings help to maximize your power output by reducing the time spent pedaling through the dead spot at the top and bottom of your pedal stroke. Which means that you'll put down more power with less effort.Yes, we're talking about free speed.

The theory behind Rotor's elliptical Q-Ring is fairly simple -- when pedaling, your legs naturally produce the greatest amount of power on the downstroke, and they produce less power when your feet are coming up over the top of the rotation. This position is also known as the dreaded 'dead-spot.' The ellipse is shaped so that as you pedal through this dead-spot. How? Well, the diameter of the section that's pulling the chain is that of a slightly smaller chainring, which spares you effort, as well as reducing the time that's spent in this sub-optimal portion of the pedal stroke. And, as you get into the most powerful portion of your pedal stroke, the diameter of the chainring increases, effectively mimicking the roll-out of a slightly larger chainring. This all adds up to more time spent where your pedal stroke is most efficient, and less time spent where it isn't. And although its counterintuitive, it feels like you're spinning smoother circles than with a traditional round ring.

The 7075-T6 aluminum that the Q-Rings are machined from is a hardened alloy that promotes long wear life. Basically, these rings are built to put in the miles. And the shifting pins make for quick shifts, even under power. These chainrings feature a five-bolt pattern with a 110mm BCD for the outer ring, and a 74mm BCD for the inner ring. These are designed specifically for Rotor's 3D mountain bike cranksets, and fitting them with other 110mm BCD cranksets may require slight modification.

The Rotor MTB Double Q-Ring Set 110x74 BCD is available in the color Black and with a 40/27t configuration.

Tech Specs

40 / 27 t
Number of Rings:
[rings] 7075-T6 aluminum
Recommended Use:
mountain biking
Bolt Circle Diameter:
[outer ring] 110 mm, [inner ring] 74 mm
Compatible Components:
Rotor 3D Mountain Crankarm
Bashguard Included:

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