Tire Size 33×12.50r20 vs 305/55r20

33x12.50r20 vs 305/55r20

The key difference between 33×12.5R20 and 305/55R20 tire sizes lies in their width, with the 33×12.5R20 being wider by 0.51 inches. We’ll break down the differences between these two sizes and help you decide which is right for you.

Tire Size 33x12.50r20 vs 305 55r20

Fitment Guide

The 33×12.5r20 is about 4% wider and 0.6% larger in overall diameter compared to the 305/55r20. This minor difference in diameter means both tires should fit the same vehicles without issue.

However, the wider width of the 33×12.5r20 may require checking for rubbing at full lock.

Ground Clearance

With a diameter 0.19 inches larger, the 33×12.5r20 provides slightly more ground clearance than the 305/55r20.

This can help prevent scrapes and damage from obstacles, benefitting off-road driving. However, the bigger diameter also causes a 0.6% lower speedometer reading.

Gas Mileage

The 305/55r20 smaller size and contact patch reduces rolling resistance, conferring better fuel efficiency than the larger 33×12.5r20.

The wider, heavier 33×12.5r20 creates more drag and rotational mass, negatively impacting gas mileage.

Ride Comfort

The 33×12.5r20 additional 0.09 inch sidewall height cushions bump better than the 305/55r20, providing a more comfortable ride over uneven terrain.

However, the 305/55r20 shorter sidewall on smooth pavement gives a more responsive, controlled ride.


Visually, the difference between these two tire sizes is minor. The 33×12.5r20 will look slightly “stretched” due to its extra sidewall height compared to the 305/55r20 shorter profile.

Subjectively, the taller sidewall of the 33×12.5r20 better suits trucks and SUVs.

33x12.5r20 in Metric

Handling & Stability

The 305/55r20 shorter sidewall enhances handling precision and quick steering response on pavement compared to the 33×12.5r20.

However, the 33×12.5r20 extra sidewall flex improves stability and traction on loose or uneven surfaces.

Noise & Vibration

The 305/55r20 transmits more road noise and vibration to the cabin due to its stiffer, shorter sidewall. In contrast, the taller 33×12.5r20 sidewall absorbs noise and vibration better for a more comfortable ride.

Durability & Wear

The 305/55r20 smaller contact patch and lower profile allow for more even treadwear and a longer lifespan than the larger, heavier 33×12.5r20.

Additionally, the 33×12.5r20 size puts more stress on suspension and drivetrain components.

Adverse Conditions

In snow and ice, the narrower 305/55r20 may cut through to the pavement better, while the wider 33×12.5r20 provides more traction in mud and off-road terrain. Both handle adverse conditions well overall.

Speedometer Reading

At the same speed, the 305/55r20 reads 0.6% higher on the speedometer than the 33×12.5r20. For example, at an actual speed of 20 mph, the 305/55r20 reads 20.11 mph, while the 33×12.5r20 reads 20 mph.

What Does 33×12 50r20 Tire Mean?

The 33×12 50r20 tire size means that the tire is 33 inches in diameter. The second number, 12.50, means the tire’s width is 12.50 inches.

The last number 20 indicates that the rim size is 20 inches. Now that we know what the numbers in 33×12 50r20 mean, let’s look at how this compares to the 305 55r20 tire size.

What Does 305/55r20 Tire Mean?

The 305 55r20 tire size is different than other sizes. The first number, 305, means the tire’s width is 305 mm. The second number, 55, represents the aspect ratio of this tire.

The last number 20, again means that the rim size is 20 inches. The letter R indicates that this is a radial tire. When converted to inches, the tire size 305/55r20 is the same as 33.2x12R20.

Is 305/55r20 the Same as 33/12.5r20?

The 305/55r20 and 33/12.5r20 tires are not exactly the same size, but they are very close in size. The 305/55r20 tire is 0.19 inches (4.78 mm) larger in diameter than the 33/12.5r20 tire, and the speedometer difference is only 0.6%.

The 305/55R20 is 0.19 inches (4.78 mm) larger in diameter than the 33/12.5R20, and the 33/12.5R20 is 3.18 inches (80.77 mm) smaller in circumference than the 305/55R20.

Will 33×12.50r20 Fit 305/55r20?

Yes, the 33×12.50r20 and 305/55r20 tires have a minimal diameter difference of 0.6%, well within the acceptable 3% range.

However, verifying load capacity is crucial to ensure it meets or exceeds the original tire for safe use.

How Much Taller Is A 305/55r20 Tire Than A 33×12 50r20?

The tire size 305/55r20 is 0.19 inches taller than the 33×12.50r20 tire, which is a 0.6% increase in diameter.

The 305/55r20 tire size is approximately 33.21 inches tall, while the 33×12.50r20 tire size is around 33.02 inches tall.

How Much Wider Is A 33×12.50R20 Tire Than A 305/55r20?

The 33×12.50R20 tire is 0.51 inches (13 mm) wider than a 305/55r20 tire, representing a 4.1% increase in width.

The tire size 305/55R20 has a width of about 12.01 inches (305mm), while the 33×12.50R20 tire size is approximately 12.52 inches (318mm) wide.

Our Observation
We observed that the differences are quite minor after comparing the 33×12.5r20 and 305/55r20 tire sizes.

While the 33×12.5r20 provides more ground clearance and cushioning for off-road use, the 305/55r20 is more responsive and efficient for on-road driving. For most drivers, either tire should perform well for general use.

Consider your priorities and intended application when choosing between these two similar options. Performance differences are modest, and both offer a capable combination of on and off-road abilities.

2 thoughts on “Tire Size 33×12.50r20 vs 305/55r20”

  1. My tire size on my 2010 Chevy Silverado 1500 truck is 305/55/r20s it’s got a 6 inch lift so can I put 33×12.50 R20 tires on this rim there 20s thank you

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