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This post compares the advantages and disadvantages of 53/39 and 52/36 road bike chainrings.

The Advantages of 53/39 Chainrings

• Higher Gearing

The main advantage of 53/39 chainrings is their large size (extra teeth) allowing the rider to pedal in a higher gear.

Ultimately, the potential speed of a bike that can be reached via pedaling is dependent on three factors:

1. Gearing
2. Wheel circumference
3. RPM (rotations of the cranks/chainring per minute)

The higher the gear, the greater the gear ratio. The gear ratio indicates the number of rotations that the rear cog and respectively the rear wheel make per 1 revolution of the cranks/chainring.

For example, if the chainring has 53 teeth and the rear cog has 12, the gear ratio would be 53:12 = 4.4. In other words, the rear wheel will rotate 4.4 times per 1 rotation of the cranks.

If the gearing was lower, the gear ratio drops too and one spin of the cranks equals fewer rotations of the rear wheel and respectively a shorter travel distance.

When the RPM and the wheel circumference are the same, a bike with higher gearing will offer a higher top speed.

For instance, the top speeds of 53/39 and 52/36 chainrings compare as follows when using 700×25 tires and pedaling at 90 RPM

Conclusion:

The extra tooth on 53 chainrings offers a 2% speed increase when all parameters (cadence, wheel circumference) are equal. In practice, this isn’t a tremendous difference and doesn’t help much with making a choice.

However, the 39T chainring offers an 8% increase in top speed. This is beneficial to riders in good shape and to those who live in flat areas allowing higher cadence.

Meanwhile, a 36T ring could end up being too small (slow) for riders aiming at maintaining a high average speed.

• Classic

53/39 was the road bike standard for many years. Some people stick with it because of the retro appeal and the familiarity.

The Disadvantages of 53/39

• Not Ideal For Hills

The main problem that a 53/39 crankset can create for you is the lack of low gearing. Lower gear ratios make it easier to ride uphill because each revolution of the cranks results in a smaller traveled distance.

For example, if the gear is 39/25, then the gear ratio would be 1.56. In other words, the rear wheel has to make only 1.56 revolutions per 1 spin of the cranks. As a result, the rider has an easier time pedaling and moving uphill.

If the gear is 36/25, the gear ratio is even lower – 1.44. The lower gear ratio that comes with the 36 chainrings will allow the rider to conquer even bigger hills with the same effort.

That said, one also has to take into consideration the size of the cassette. For instance, if a 53/39 crankset is combined with an 11-34 cassette, the lowest gear ratio is 1.14. Meanwhile, a 52/36 crankset combined with an 11-25 cassette gives us a 1.44 ratio.

• Stress on the Joints

Higher gear ratios demand more power from the rider and increase the stress on joints. For that reason, people who are in the process of healing an injury stick to lower gearing.

The Advantages of 52/36 Chainrings

• Low Gearing

As explained, a 36T chainring offers substantially lower gearing than a 39T unit when using the same cassette. This property will be beneficial to people who don’t race and/or live in a hilly area. Another benefit is the reduced stress on the joints.

• Lighter

When all parameters are equal (build quality, materials…etc.) smaller chainrings are lighter. That said, the discrepancy is very small and inconsequential to most riders.

• Large Drop

The drop from a 53 chainring to a 39 one is smaller than the drop from a 52 to a 36. The larger drop will require additional shifts at the back to get in adequate gear for maintaining a smooth cadence.

Summary: What You Need To Know

• The difference between a 52T and a 53T chainring is not substantial enough to make a choice based on it. If you are in a situation where a 52T chainring spins out*, a 53T unit will more than likely have the same destiny. Also, the extra speed offered by a 53T is too small (2%) to matter in practice.

• The difference between a 39T chainring and a 36T model is much more perceivable (8%). If you are in good shape, a 39T chainring will work just fine, but if you live in a very hilly area and have some joint issues a smaller chainring could be a better choice, at least temporarily.

• You can get the best of both worlds by combining a 53/39 crankset with a wide-range cassette such as 11-32/34. The downside of this approach is that wide-range cassettes have higher gaps between the gears making it more difficult to maintain a smooth cadence.

* spinning out occurs when the wheels of the bicycle are rotating at a speed faster than the one that the rider can reach via pedaling. When that happens, it becomes pointless to pedal because the motion does not contribute anymore. Another downside of spinning out is the lower control.