A Short History of Elliptical Chainrings

 Q-rings, by Rotor, are popular with triathletes and time trialists because they're supposed to even-out the dead spots in your pedal stroke. Which is to say, you get a little push when your pedals are straight up and down. They do this by making the chainring oblong and a little off-center. Sheldon Brown explains it better that I can.

The Big question is whether it actually works or not. Mike Burrows, designer of the modern road bike frame, says no. He says the human leg is like a piston engine, it can't push all the time, it needs a moment to re-fresh. The elliptical chainring makes the leg constantly tense, which he says constricts blood flow.

Scientific tests are inconclusive, as are the more subjective inquiries. Personally, I've used Biopace and Q-rings, and can't tell the difference, except I drop the chain more with Biopace rings than normal round rings.

Point is, it's not a new idea. The concept has been around since the 1890's at least. Take this 1893 Columbia:

This bike is especially nonsensical because it's also a fixed-gear, so the chain might hop off the wheel at the point when the chainring is smallest.

The most famous elliptical chainring belongs to Shimano, with their Biopace line, that infected the market in the '80s and '90s. Instead of an oval, the Biopace ring is more of a bumpy circle. It was computer designed to even-out the motion of the moving leg, or whatever, so there: 

There are thousands of community shops out there with parts-bins full of Biopace rings, so if you want to try it out, check with your local non-profit. 

The latest and possibly best-marketed oblong chainring belongs to Rotor, with the Q-ring. The idea here is that you choose the best spot for the oblong shape based on your personal pedal stroke. The crank-to-chainring holes are drilled in a circle, rather than a 5-point spline, so you can move it around. Still, you have to get the correct BCD for the crank brand and model. 

My feeling on Q-rings, as with most bike stuff, is that they're fantastically marketed baloney. Also, as a mechanic, it's a pain in the ass to get the front derailleur adjustment perfect. You have to set it for the highest setting, and the chain still drops and skips sometimes. Oddly enough, on the old SRAM Red group, the one with the worst front derailleur in history, the Q-rings actually helped a little. So, I guess they aren't completely useless. 

Check back in a few weeks for my new updates. Ride on, Cylon. 

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