Oval Chainring: Advantages and Disadvantages

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The chainring on your bicycle is responsible for transferring energy from the pedals to the drivetrain. For most of the history of bicycles, the chainring has been circular. In recent years, oval chainrings have emerged as an alternative to traditional options.

Many people claim that using a non-circular chainring helps increase climbing power and smooth out your pedal stroke. Switching to an oval-shaped chainring may increase your comfort and overall efficiency when pedaling uphill or long distances.

Osymetric oval chainring

Yet, some people claim that oval chainrings hurt their performance. Oval chainrings also tend to cost more than traditional options.

So, should you switch the chainring on your bicycle?

Keep reading to explore the advantages and disadvantages of using an oval chainring.

What is an oval chainring?

Oval chainrings first appeared in the 1990s but became popular only in the past decade. Also called an elliptical chainring, the oval chainring has an oval or elliptical shape. It resembles a circle slightly flattened in the middle.

absoluteBLACK oval chainring
An oval chainring from absoluteBLACK. (© Glory Cycles | Creative Commons)

The shape of the ring is designed to optimize your pedal stroke and transfer energy from the pedals to the chain more efficiently.

What does an oval chainring do?

Traditional bicycle cranks have circular chainrings. The circle shape of the ring creates weak spots in your pedal stroke. Your pedaling action requires more energy when your feet reach the 12 o’clock and 6 o’clock positions.

Side view of a road bike's circular chainring
A traditional circular chainring. (© Mark Walker | Creative Commons)

The 12-to-6 position occurs when one foot is fully extended and the other is contracted. You are more likely to notice increased resistance as you pedal uphill or change to lower gears.

The extra effort that you need to complete a rotation with a standard crankset can lead to unnecessary stress on your body. You may experience extra strain on your knees. Back in the 1990s, someone decided to solve this problem by flattening the shape of the chainring.

An oval chainring eliminates the dead spot in your pedal stroke that occurs when one leg is up and the other is down. You get a smoother rotation of the pedals.

Unfortunately, when non-round chainrings first appeared, they failed to solve the problem. The original designs did not include the optimal shape for transitioning from the front teeth of the ring to the shorter sides.

Over the years, manufacturers improved the design and determined the best shape and size. The latest oval rings are more effective at improving the power output when pedaling.

Now let’s look at the pros and cons of an oval chainring.

What is the benefit of an Oval chainring?

Oval chainrings were designed to optimize delivery of power from your pedaling. Some of the advantages provided by non-round rings include:

Keep in mind that everyone has different results when using an oval-shaped chainring. Some people experience no noticeable change in their performance while others will never go back to a circular chainring. Here is a closer look at the benefits.

Increased pedaling efficiency

A standard circle-shaped chainring limits the efficiency of your pedaling. It creates a dead spot in your pedal stroke when your legs reach the 6 o’clock and 12 o’clock positions.

The oval ring offers a smoother rotation, which increases the efficiency of your pedaling. The shape of the ring creates a smaller radius when the cranks are in a vertical position, which lowers the effective gear that you pedal with.

As your legs rotate, the oval ring reaches its horizontal position. At the horizontal position, the chainring effectively creates a higher gear. This allows you to exert less effort when pushing to a higher gear.

You may find the increased efficiency beneficial when traveling on uneven terrain, climbing uphill, or dealing with slippery surfaces. However, many people switch to oval rings to help protect their knees.

Less stress on your knees

Knee pain is a common problem for cyclists. One study found that about 94 per cent of professional cyclists experience knee pain and other overuse injuries each year.

Racing cyclist's knee, viewed from the side
Taking strain off the knees is one of the big potential advantages of an oval chainring.

Stress on your knees can occur for a variety of reasons, including:

  • The seat is too high
  • The saddle is too far forward
  • Feet are too close or far apart
  • You overexert yourself
  • The dead spot adds more strain

Switching to an oval chainring will not eliminate all these issues. However, it can eliminate strain caused by the dead spot on a standard chainring.

With a circle chainring, you may experience extra resistance when coming out of the 12-to-6 position. The resistance and uneven pedaling may leave your knees feeling sore after a long ride.

An oval chainring reduces stress on the knees by evening out your pedal stroke. You place less pressure on the joints in your knees.

Easier climbing

Cyclist exerting himself as he climbs uphill on a road
With a standard circular chainring, climbing will reveal the most challenging parts of the pedal stroke. It should be less obvious with an oval chainring.

One of the most common reasons to use an oval chainring is for better climbing performance. The oval shape maximizes the energy produced on the power phase of your stroke and minimizes resistance coming out of the recovery phase.

When climbing with an oval chainring, you should notice smoother pedaling action. The smoother delivery is easier on the legs, allowing you to go faster with less effort.

More traction and torque on the rear wheel

An oval chainring should help smooth out your pedal stroke, which helps increase torque on the rear wheel. You get more power and traction thanks to the increased torque.

The extra traction and torque come in handy when riding on uneven or unstable terrain, such as gravel or snow. You are less likely to spin the rear wheel when traveling across loose terrain, which may also help limit stress on your knees.

Oval chainring disadvantages

Oval chainrings have been around long enough for researchers to verify the advantages of the elliptical shape. However, oval rings also come with a few potential disadvantages:

Another possible issue is installing the new chainring. Switching to an oval ring requires you to remove the crankset, swap out the chainring, and adjust the derailleur. If you do not want to deal with these steps, you may need to take your bike into a shop, which adds to the cost of switching to an oval ring.

Oval chainrings typically cost more

Oval chainrings are not as common as circle chainrings. As they are still considered specialty items, they tend to cost more.

Quality oval rings often start at $100. However, you can easily spend $200 on a chainring from one of the top brands.

Circle chainrings have an average cost of $15 to $50. You also have a much wider selection of options, as circle chainrings are more common. However, if you are serious about improving your cycling performance, the cost of an oval chainring is likely worth it.

Your pedal stroke may feel awkward

Switching from a circle chainring to an oval one requires an adjustment period. Most people get used to the difference in their pedal stroke, but others never get over the change.

You may find that your pedaling feels awkward after adding an oval chainring. After years of using a circle chainring, you may not adapt to the change quickly.

Potential stress on your knees

Some people experience less knee pain after switching to an oval chainring while others experience additional pain. The jerky, uneven pedal stroke created by a circle chainring is known to place extra pressure on your knees. However, not everyone experiences knee problems.

As mentioned, if you can maintain a smooth pedal stroke with a circle chainring, switching to an oval one may feel awkward. The change in your pedaling style forces you to use your muscles differently, which may cause knee pain.

Luckily, most people have the opposite reaction. Everyone is different and the potential drawbacks depend on your riding style and preferences.

Who should use an oval chainring?

Oval chainrings are best suited for mountain biking and long-distance rides with lots of climbing. You are likely to get more out of the oval chainring when climbing or needing more traction from the rear wheel, which is why oval rings are often used on mountain bikes.

The typical road cyclist may not enjoy the same benefits compared to mountain biker. When traveling short distances on flat asphalt, you are less likely to need to switch gears. The smoother ride reduces the potential improvements of switching to an elliptical chainring.

Studies also indicate that an oval chainring may be more beneficial for weaker riders. Stronger riders experience less resistance when switching between the power phase and recovery phase of their pedal strokes. An oval-shaped ring may allow weaker riders to pedal more smoothly and efficiently.

The bottom line is that oval chainrings may not provide noticeable improvements for every cyclist. The only way to test the impact of an oval ring is to try one for yourself.

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04/12/2024 06:05 pm GMT

When looking for an oval chainring, choose a ring with the same number of teeth as your current chainring so as not to drastically alter your gear ratios. Test out the difference for a few weeks, as you may need to adapt your riding style to fully enjoy the benefits.

If you are not happy with the results, switch back to your standard circle-shaped chainring.

Image at top: © Glory Cycles | Creative Commons