Is a 3.73 gear ratio good for towing?

The 3.73 axle ratio is typically a solid middle-ground for towing, offering enough low-end torque to pull a trailer up hills while preserving reasonable highway fuel economy. For very heavy trailers or sustained mountain towing, enthusiasts often opt for a taller gear like 4.10 or 4.56; for lighter towing or maximum highway efficiency, a lower ratio around 3.31–3.42 may be preferable.

What the 3.73 ratio does in towing scenarios

Understanding how gearing works helps explain why 3.73 is chosen. A higher numerical ratio (like 3.73) multiplies engine torque more than a lower ratio, which helps when starting from a stop and when climbing steep grades. However, at highway speeds, a higher ratio also means the engine runs at higher RPMs for the same road speed, which can affect fuel economy and cabin noise. Tire size and transmission gearing also influence the real-world feel of 3.73, so the impact isn’t purely about the axle number alone.

Before examining lists of pros and cons, keep in mind that towing performance is a system issue. Engine torque, transmission gear steps, cooling capacity, hitch setup, and even trailer weight distribution all interact with the axle ratio. The following sections summarize the main practical implications for most light-to-moderate and mid-range towing duties.

Pros and cons of using a 3.73 axle for towing

Below is a quick look at the strengths and limitations you’re likely to notice with a 3.73 gear ratio when towing.

• Improved hill-climbing ability and easier starts with a loaded trailer thanks to greater torque multiplication.


• Better response in lower gears for overtaking or merging when towing in mixed terrain.


• Generally compatible with a wide range of gasoline and diesel engines, especially those paired with mid-range transmissions.


• Balanced performance for typical everyday towing without pushing into extreme speeds or very heavy trailers.

In short, 3.73 tends to be a pragmatic compromise for many towing setups, delivering usable low-end power without dramatically sacrificing highway efficiency for average loads.

Limitations and caveats to consider

Every gearing choice has trade-offs. The following caveats help set expectations for 3.73 in real-world use.

• Higher engine RPMs at highway speeds compared with lower numerical gears, which can reduce fuel economy and increase road noise on long highway trips.


• For very heavy trailers, or environments with frequent steep grades, a taller ratio (like 4.10 or 4.56) may yield better overall performance and towing comfort.


• With larger or smaller tire sizes, or unusual transmission programming, the perceived gearing can shift, altering acceleration feel and MPG.

These considerations mean that while 3.73 is versatile, it isn’t the universal best choice for every trailer weight or every driving condition.

When to choose 3.73 versus other ratios

Context matters. Here are guidance-style scenarios to help decide how well a 3.73 might fit your setup.

• Ideal for: Towing moderate trailers on mixed terrains, where you benefit from solid low-end power without sacrificing too much highway efficiency.


• Consider a taller ratio (4.10/4.56) if you regularly tow very heavy loads, drive in mountainous regions, or want maximum hill performance and engine braking from lower gears.


• Consider a lower ratio (3.31–3.42) if your trailer is light, most towing is on flat highways, and you want the best possible high-speed fuel economy and lower engine noise.

Choosing the right ratio is about matching your typical trailer weight, terrain, and driving style to the vehicle’s engine and transmission characteristics.

Practical tips for maximizing towing with a 3.73 setup

To get the most from a 3.73 axle when towing, consider these practical steps:

• Use tow/haul mode if your vehicle offers it to optimize transmission shifts under load.


• Keep hitch weight within the recommended range and use a weight-distribution hitch for better stability.


• Monitor engine temperature and transmission temperature during long climbs or slow, heavy-tueling; upgrade cooling if necessary.


• Be mindful of tire size changes; larger or smaller tires alter effective gearing and can shift towing performance.

These actions help you leverage the benefits of a 3.73 ratio while mitigating potential downsides during towing sessions.

Summary

A 3.73 axle ratio is a versatile, common choice for towing that offers solid low-end torque for hill starts and confident acceleration with a trailer, while maintaining reasonable highway performance. It’s a sensible middle ground for many owners, but not the best fit for extremely heavy trailers or for those chasing maximum highway fuel economy. Always consider engine torque, transmission tuning, trailer weight, tire size, and terrain, and consult your vehicle’s manual or dealer guidance when evaluating gearing options for towing.

What are the benefits of 3.73 gears?

The main benefits of 3.73 gears are improved acceleration and better pulling power, ideal for performance driving, off-roading, and towing. This is because they increase the torque sent to the wheels, allowing a vehicle to accelerate faster and handle heavier loads more effectively. The downside is that 3.73 gears can lead to lower fuel economy and higher engine RPMs at highway speeds compared to taller gears. 
Improved acceleration and performance 

• Increased torque: 3.73 gears provide more torque multiplication, which results in quicker acceleration from a stop and in the mid-range. 
• Better "off the line" feel: This gear ratio can make a vehicle feel much more responsive, especially when compared to lower ratios like 3.08 or 3.21. 
• More power in the powerband: For many vehicles, 3.73 gears place the engine in a more optimal powerband for street driving, making it feel less "lugging". 
• Good for racing/performance: The enhanced acceleration is ideal for drag strip performance or performance street driving. 

Enhanced towing and load-carrying capacity 

• Better for towing: The increased torque is beneficial for pulling heavy trailers, as it provides more pulling power. 
• Handles heavy loads: This gear ratio can be ideal for trucks that are regularly used for hauling or for off-roading with heavy equipment. 

Potential downsides

• Lower fuel economy: Because the engine runs at a higher RPM for a given speed, gas mileage often decreases, especially on the highway. 
• Higher highway RPMs: At highway speeds, you will likely be turning higher RPMs, which can increase engine noise and may be less desirable for long-distance cruising. 
• Potential overdrive pairing issues: If you have an overdrive transmission, 3.73 gears might need to be paired with the correct overdrive gear to balance highway cruising and city performance. 

Is a 3.73 axle ratio good for towing?

Yes, a 3.73 axle ratio is good for towing, as it provides a good balance between towing power and fuel economy, and is considered a strong choice for those who tow regularly but also drive their trucks daily. It offers more torque for pulling heavy loads than lower ratios like 3.55, and is better for fuel efficiency and a quieter ride on the highway than higher ratios like 4.10 or 4.30. 
This video explains the relationship between gear ratios and towing: 50sFISHER’S OFF-ROADYouTube · Jan 23, 2025
Benefits of a 3.73 axle ratio for towing

• Increased torque: A 3.73 ratio provides more torque than lower ratios, making it easier to accelerate with a heavy trailer and climb hills. 
• Good for occasional to frequent towing: It's a popular and versatile choice for owners who tow regularly but don't need the extreme towing capacity of higher ratios. 
• Better fuel economy than higher ratios: When cruising on the highway, the engine will be at lower RPMs compared to a truck with a higher axle ratio (like 4.10 or 4.30), resulting in better fuel economy. 
• Strong all-around performance: It offers a good compromise for a daily driver that is also used for towing, providing quicker acceleration around town compared to lower gear ratios. 

When a 3.73 ratio might not be enough 

• Very heavy loads: If you frequently tow very heavy loads, especially in mountainous terrain, a higher ratio like 4.10 or 4.30 may provide a better experience by keeping the engine out of lower gears. 
• Large off-road tires: Adding larger tires can decrease the effective gear ratio, so if you plan on installing oversized tires, a higher starting ratio like 3.73 may be necessary to compensate for the larger tire diameter. 

What is the 80 20 rule for towing?

The "80/20 rule" for towing is a guideline suggesting you should not tow a trailer with a Gross Vehicle Weight Rating (GVWR) that exceeds 80% of your vehicle's maximum towing capacity. This provides a 20% buffer for safety, comfort, and to account for variables like extra gear, passengers, and road conditions. The primary benefits are improved safety, reduced wear and tear on the vehicle, and better control.
 
Why the 80/20 rule is recommended 
This video explains the 80/20 towing rule and why it's important: 54sThe Northwoods RV LifeYouTube · Jan 23, 2022

• Improves safety: It helps maintain better control, especially during emergencies, on steep inclines, or in windy conditions. 
• Reduces vehicle strain: Operating below the maximum limit reduces stress on your engine, brakes, and transmission, which can prolong their lifespan. 
• Accounts for real-world variables: The rule provides a buffer for factors not always accounted for in the manufacturer's ratings, such as cargo, passengers, and variations in road conditions. 
• Prevents overloading: It's a simple way to avoid exceeding your vehicle's limits, which can be illegal and dangerous, and could lead to breakdowns or frame damage. 

How to apply the rule

1. Find your vehicle's max towing capacity: Check your owner's manual or the sticker on the driver's side doorjamb for the maximum weight your vehicle is rated to tow. 
2. Calculate 80%: Multiply your vehicle's max towing capacity by 0.800.800.80 to find your recommended maximum trailer weight. 
   • Example: If your vehicle's max towing capacity is 10,00010 comma 00010,000 lbs, your 80% target is 10,000×0.80=8,00010 comma 000 cross 0.80 equals 8 comma 00010,000×0.80=8,000 lbs. 
3. Verify trailer weight: Ensure the trailer's GVWR is less than your calculated 80% limit. 

What is the best gear ratio for towing?

The best gear ratio for towing depends on the type of towing and driving conditions, but generally, a higher numerical ratio (e.g., 3.73 or 4.10) is better for towing, as it provides more torque for pulling heavy loads. Conversely, a lower numerical ratio (e.g., 3.23 or 3.55) is better for fuel economy on the highway but offers less towing power.
 
This video explains the different gear ratios and when to use them for towing: 1mGREYWOLF RVYouTube · Jul 20, 2025
Higher numerical gear ratios (e.g., 3.73, 4.10) 

• Best for: Heavy towing, steep inclines, or frequent towing. 
• How it works: A higher number means the engine turns more times for each rotation of the wheels, which multiplies torque and makes it easier to get a heavy load moving and maintain speed. 
• Downside: Decreased fuel economy and higher engine RPM at highway speeds. 

Lower numerical gear ratios (e.g., 3.23, 3.55) 

• Best for: Light towing or everyday driving with less frequent or lighter loads. 
• How it works: The engine doesn't have to work as hard at highway speeds, leading to better fuel efficiency. 
• Downside: Less torque for pulling heavy loads, which can strain the engine and transmission. 

Choosing the right ratio

• For occasional or light towing: A ratio around 3.55 may be a good compromise between towing ability and fuel economy. 
• For heavy or frequent towing: Look for a ratio of 3.73 or higher. Ratios like 4.10 or 4.56 offer even more towing advantage but will significantly reduce fuel economy. 
• Consider your vehicle: The best ratio also depends on the vehicle's engine, transmission, and the weight of the trailer. Always check your vehicle's specific towing capacity and consult the owner's manual.