Should you use an oval chainring for cyclocross and gravel cycling?

July 03, 2020

Oval (elliptical) chainrings continue to gain in popularity, having been spotted on bikes belonging to pros like Chris Froome and other elite athletes. Simultaneously, many cyclocross and gravel bikes are abandoning double cranksets and front derailleurs in favor of lighter, simpler, "1x" drivetrains, based around a single chainring. 

If you're taking the plunge and moving to a 1x setup, should you also consider making that new chainring an oval? Yes! Let's talk about why. 

What are oval chainrings? 

Oval chainrings use an elliptical (non-round) shape. The stock rings that came on your bike are very likely perfectly round. Oval rings are shaped more like an egg. 

Today's oval chainrings have nothing to do with Shimano's "Biopace" rings from the 1980's. Biopace rings actually had the exact opposite design compared with modern oval rings - they made pedaling too difficult in the dead zone and too easy in the power zone. 

What are the benefits? 

When riding a bicycle, you can't produce a consistent power output throughout the rotation of the pedals. You have "dead spots". By varying in diameter, oval rings change the amount of leverage - increasing your pedaling effectiveness. You can push harder and reduce fatigue. 

Of particular note for cyclocross riders: oval chainrings can help improve traction on steep, loose, slippery climbs where you struggle to maintain grip. 

Why should I use a "1x" drivetrain?  

Switching to a single chainring drivetrain has some key benefits: 

  • Your bike is lighter (you remove a front derailleur and one chainring)
  • Your bike is simpler and easier to clean
  • It's easier to shift with less brain power - it no longer matters which front chainring the chain is on. You don't have to worry about cross-chaining. 

You still see double chainrings, especially at the elite levels. Those riders can turn a 46 tooth ring and benefit from (and need) a wide-range double drivetrain. If you aren't good enough to race in Europe, however, a 1x setup can work great for you. 

Who makes oval chainrings for cyclocross and gravel? 

Popular brands include Wolf Tooth, AbsoluteBLACK, Ride1Up, and others. When considering a chainring purchase, look for compatibility with your crankset and drivetrain. You'll also want a chainring that uses a "narrow-wide" tooth design to help retain the chain, since you no longer have a front derailleur. 

Compatibility of oval rings

There are a few things to know: 

  • oval chainrings don't change the required chain length or the rear derailleur you can use
  • Generally, brands recommend that you replace your round chainring with an oval that has the same number of teeth
  • Your new oval chainring needs to exactly match the required mounting pattern of your crankset

Who should consider oval chainrings? 

If you're not riding a 1x drivetrain yet but are considering switching, an oval ring is a no-brainer. Kill two birds with one stone and make the jump to oval at the same time you go 1x. 

Want to stick with a traditional double chainring drivetrain? The decision is less clear. While oval chainrings are available in double chainring configurations also, nothing shifts as well with a front derailleur than Shimano's stock rings. 

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