Not to be confused with Shimano’s Biopace of the late ’80s, rotor Q-rings may look similar, but that’s where the similarities end. They’ve already been adopted by a handful of the biggest names in the sport, sometimes to the chagrin of their sponsors.
History can be a funny thing. Back in the late ’80s, Shimano introduced a radical new concept in chainring design with their elliptical Biopace chainrings. The theory behind Biopace was to have the small radius correspond with the power part of the pedal stroke, creating foot speed to push through the larger radius at the stroke’s dead-spot. Despite Shimano’s best promotional efforts, Biopace chainrings came, stayed briefly, then disappeared. If there was ever a gag in the bike industry that would make for ongoing material for late-night comics, Biopace chainrings would be it. Although some people admired the concept, elliptical chainrings were thought to be dead and gone. Apparently, however, there were cyclists in Spain who missed the humor that surrounded Biopace and forged ahead with an elliptical crank system of their own design.
Rotor cranks have been around for quite some time. The earliest versions were very strange looking, and to say they’ve been the target of slings and arrows over the years would be an understatement. However, Rotor has steadfastly stayed in the game and the product has evolved greatly. In fact, a funny thing happened along the way— they were embraced by some of the best riders in the world. And not only by the sponsored pros using their Q-rings, but also non-Rotor-sponsored pros using the rings and covering over the logos to appease their round-ring sponsors. Pro riders are, of course, some of the hardest to win over with new ideas, especially when it comes to altering their pedal stroke.
As a Paris-Roubaix podium finisher, Roger Hammond knows something about laying down the power. With his left foot in the 3 o’clock position, he’s pushing the equivalent of a 56-tooth chainring. (Photo: Yuzuru Sunada)
THE TECH
Rotor is actually more than just a crank and chainring maker, but it’s those parts that define their existence. In the most basic terms, the Rotor chainring philosophy boils down to this: around the upper dead-spot of the pedal stroke, a 53-tooth Rotor Q-ring is equivalent to pushing a 51-tooth gear. But as the pedal goes down and more strength is applied, the equivalent chainring tooth size reaches 56-tooth gear. Could it be that simple?
When we dove into the tech info on the Q-rings, we initially thought we might need an engineering degree to make sense of it all. But when we looked at the biomechanics of the pedal stroke, and at which point the most power was being made, it all started to make sense. By looking at your pedal stroke in terms of the face on a clock, the most power generated is between the 1 to 5 o’clock position. The Q-rings are designed to have the timing of the ellipse’s larger diameter portion match the powerful 1 to 5 o’clock position of the stroke. While gear inches increase during the power part of the stroke, the Q-ring, in turn, reduces the gear inches during the least powerful parts of the stroke, which is the 11 to 1 o’clock and 5 to 7 o’clock positions, helping speed through the less powerful portion.
Rotor’s 3D alloy CNC-machined crank is one of the coolest cranks we’ve seen in quite some time. The aluminum arms use Rotor’s own Trinity Drilling System, creating three holes drilled from end-to-end and removing excess material from the core while still maintaining needed strength and stiffness. Rotor offers the alloy 3D crank in standard, compact and Campagnolo sizes. Our test cranks came with a steel spindle, but for $200 more, you can save 35 grams and opt for the titanium version.
Similar to the 3D cranks, the Q-rings are also CNC-machined and really show off Rotor’s knack for craftsmanship. The 39- and 53-tooth rings started as chunks of aluminum that have been machined into 4mm-thick precision tools. The big ring has four shifting pins in addition to machined ramps that help pull the chain up from the small ring when shifting. Knowing that not everyone needs a new crank, the Q-rings will retrofit non-Rotor cranks as well.
The CNC machine work on the 3D cranks and Q-rings is impressive. Every extra bit of material that isn’t necessary is removed to shave weight.
SETUP
Rotor’s OCP (Optimum Chainring Position) design gives you numerous options for the chainring orientation, so riders can fine-tune their own setting. Rotor has three settings that they recommend starting from: positions 1, 3 and 5. The markers on the chainrings make the setup process simple enough so that you don’t need to be a USA Cycling-certified mechanic to figure it out.
We mounted our standard 53x39 Q-rings onto the 3D cranks and chose the third setting on the rings. Once the rings were mounted, the cranks went on the same as any other outboard bearing crank. We did have to raise the front derailleur a few millimeters to keep the big ring from hitting it when at its highest point.
THE RIDE
The expectation among testers was that they would feel like they were pedaling squares, and their normal stroke would be thrown off, but this was hardly the case. Immediately, pedaling felt smooth and natural, not at all choppy as some skeptics had anticipated. Even the testers with the smoothest pedal strokes noticed instant efficiency gains from the Q-ring’s smoothing effect. The smoothing out of the stroke gave more of an even feel of power, regardless of where we were in the stroke.
After spending the first couple rides on flat roads, we decided it was time to head for the hills. Since longer climbs are about finding a steady rhythm, this played into the Q-ring’s strength, offering a smooth, powerful stroke while seated. With round chainrings, an all-out sprint or out-of-the-saddle climbing results in a push-pull movement, rather than a smooth stroke like when seated. But, this was where the Q-rings made the biggest impact. Instead of a stroke with huge power fluctuations, the Qrings gave the feel of consistent force on the pedals throughout the entire stroke.
THE VERDICT
We definitely feel that the Q-Rings can improve pedaling efficiency, resulting in a slight power increase. Racers have the most to gain from the Q-rings, because a small percent increase in power can be a huge difference on the race course. While it’s not going to make a new rider out of you, it can help you get every extra bit out of your pedal stroke.
Would we buy the Rotor 3D cranks and Q-rings? Yes and no. Although the 3D cranks are really cool, you probably don’t need to shell out the $400, unless you’re building up a new bike or are just in the market for new cranks. We do think the Q-rings are a worthy investment for any rider looking to gain a few watts, and would definitely recommend using them with your current cranks.
STATS
Price: $400 3D cranks; $265 Q-rings (set of 53x39 tooth rings)
Weight: 687 grams, 3D cranks and Q-rings
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