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Pedal Power: Do Elliptical Chainrings Really Work?

Elliptical Chainrings are making a comeback.

Elliptical Chainrings are making a comeback. In 2008 Carlos Sastre won the Tour de France with a decisive attack riding on Rotor’s elliptical Q-Rings. Last year the Cervelo Test Team raced on Q-Rings, too.

According to Rotor, Q-Rings increase the power in your pedal stroke by minimizing the loss of power during the dead spot – usually the top and bottom part of the stroke (if you picture a clock, from 11 to 1 o’clock and five to seven o’clock).

The question is, do Rotor chainrings really work? The $299 price tag might be worth it if they help you go faster.

Rotor is not the first company to make non-round chainrings.  Over the past 30 years several companies have played with the idea, most notably Shimano, who once sold what they called Biopace chainrings.

Rotor’s Q-Rings concept is that a cyclist’s muscles are strongest on the pushing down-phase of the pedal stroke, and weakest at the top and bottom of the stroke. Rotor took a 53 tooth chainring and ovalized it, so that the power, or pushing down, phase would be effectively like using a 56-tooth chainring, while the weakest phases (the top and bottom of the pedal stroke) the equivalent of only 50.7 teeth, minimizing the time spent in this ‘dead phase.’

Two main things set Q-Rings apart: the smooth oval shape causes less strain on the knees than earlier elliptical chainrings and they can be adjusted to five different settings to match your riding position. (There is also the added bonus of putting bling on your bike, too.)

I rode a pair of Q-Rings for most of last season. I could feel my quads spent more time pushing down in the power position of the stroke. I also noted that while my quads were doing more work, my hamstrings were also being taxed during the pulling up phase of the pedal stroke. It took more than two weeks before my hamstrings adapted to the increased work load.

The only real drawback was that getting my front derailleur to work well was tricky because it wasn’t designed with a 56 tooth clearance in mind. The problem was fixed, however, when Rotor sent me an additional spacer.

In addition to my own experience, a long time friend and California State University Bakersfield professor, Jeff Moffit (Ed.D.) did a study on the effect of Q-Rings on cycling economy.

Subjects completed a 30 km time trial, with data recorded at the 10km and 20km marks and at the finish. The study found no conclusive performance advantage to using Q-Rings, but also that there was no disadvantage over longer distances either.

The bottom line is that there is no such thing as free energy.  By having more time spent in the power phase, the muscles will be limited by the build-up of lactic acid. Some studies have shown that there are potential benefits from Q-Rings during anaerobic efforts of 30 seconds or less. These benefits are not applicable to triathletes, however, as these anaerobic efforts simply do not occur during a triathlon bike leg.

Because the Q-Rings limit time in the stroke’s “dead spot,” I found that I was able to ride comfortably at a lower cadence than normal. At higher speeds I was still able to spin quickly. Effectively, Q-Rings did give me a larger range of gears. I am not sure how they would affect run splits. While they will help to strengthen your hamstrings during training, which may help your running, as since they tax hamstrings a little more than round rings, your hamstrings may be more fatigued starting the run.

Will I continue to use them?  It felt comfortable to be pedaling circles again when I went back to riding round chainrings in October. Since I know that Q-rings won’t harm me and could, in fact, help my performance, I will most likely be riding them again for 2010.

Chainring Basics:

Many triathletes have no idea what the various parts of their bikes are called – if you’re one of those and can’t figure out what a chainring is, here’s a quick primer:

  • The gears on your bike consist of (usually) two chainrings at the front and anywhere from nine to 11 gears, or cogs, at the back.
  • The larger the chainring, the harder the gear and the more power you can generate.
  • Your gears, or cogs, attached to your rear hub work opposite – the larger the cog at the back (towards the inside), the easier the gear.
  • Typically derailleurs (or shifters) are set up so that the right shifter changes your rear derailleur (moves the chain to an easier or harder gear) while the left shifter changes the front derailleur, which moves you from your easier (smaller) to harder chainring.
  • Most triathlon bikes come equipped with a 42/ 52 chainring combination, meaning the small chainring has 42 teeth while the big chainring has 52 teeth.
  • More powerful athletes will sometimes use larger chainrings – up to 55 or 56 teeth is not unusual for some triathletes and many professional cyclists.

Nat Faulkner is spending this winter teaching bike skills in Tucson for personalbest.ca training camps.