When it comes to competitive cycling, everyone is on the lookout for an edge. That’s why two teammates on UK-based Team Sky decided to use oval chainrings. In 2012, Bradley Wiggins won the Tour de France using oval chainrings while teammate Chris Froome did the same in 2013 and 2015. So what’s the deal with oval chainrings? And do they actually provide an advantage?
What are Oval Chainrings?
Oval (or “osymetric”) chainrings are an alternative to the round chainrings that come standard on every bike. Chainrings are attached to the crank arms and serve as the power source of your bike. During the pedal stroke, power is not displaced evenly at all angles. Most of the power comes when the crank arm is roughly parallel to the ground. Conversely, the least amount of power comes when your crank arm is roughly perpendicular to the ground.
Oval chainrings are designed to exploit this difference by effectively providing more teeth to pull the chain when the rider displaces the most power – that is, when the crank arm is parallel to the ground. In theory, this should create a more efficient stroke.
Research Results are Mixed
Several papers have been published that test whether or not oval chainrings add any value.
The Journal of Sports Science and Medicine recently published a report in 2014 that analyzed various metrics in 12 elite male cyclists, including power output, oxygen consumption, and lactic acid build-up. According to their results, oval chainrings did not provide a statistically significant advantage over round chainrings.
Another study published in the International Journal of Sports Physiology and Performance in 2010 compared the results of a 10 km time trial by cyclists using oval vs. round chainrings. Findings were similar. According to the authors, perceived exertion and power output were similar when using oval vs. round chainrings. Interestingly, the author also reported a statistically significant increase in heart rate in cyclists using oval chainrings. This is counter to the claim that oval chainrings are more efficient.
Finally, another study published in the European Journal of Applied Physiology 2004 again analyzed various metrics (including heart rate, oxygen uptake, carbon dioxide output, ventilation) from various riders. Again, they found no statistically significant difference in oval vs. round chainrings.
Helpful for Mountain Biking
Despite the mixed results with a small subset of road cyclists, there is increasing opinion that oval chainrings can provide an advantage with mountain bikers. This is particularly true when navigating loose or wet terrain, which is prone to spin-outs. By spreading the force throughout the pedal stroke, the chances of spinning out are reduced.
Psychological Edge
While there appears to be some benefit using oval chainrings for mountain bikers, the benefit for road bikers is mixed. Given this, why would anyone bother to install them? Well, when you race for living like Bradley Wiggins or Chris Froome, you’re constantly seeking an edge - regardless of how small - over your competitors.
It can also be argued that any “perceived advantage”, regardless of whether it is actually true, increases confidence on the bike. And that increase confidence translates into increased performance. There are examples of this phenomena everywhere. It’s called the placebo effect.
Installation May Require Adjustments
One con many agree on when using oval chainrings is the degradation in shifting quality and increased likelihood of dropping a chain. This is because the shifting mechanics on every bicycle are optimized for round chainrings. So if you do decide on using oval chainrings, you may need to make some minor adjustments such as moving your front derailleur towards the back of the bike to accommodate the curvature of the chain ring. Unless adjustments are made, shifting may be impacted. Consider bringing your bike to a mechanic to ensure proper installation.
Still confused? Try them for yourself! ZestyBike has a wide assortment of oval chainrings in multiple sizes and colors, all at an affordable price. Why not grab one today? You may just outlast your friends on the next trail!