Understanding the Twin Traction Beam (TTB): A Guide

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Twin I-Beam Suspension in Bullnose Ford Trucks (1980-1986)

When it comes to Bullnose Ford trucks, one feature that stands out is the Twin Traction Beam (TTB) suspension. For Ford enthusiasts the TTB is both a marvel of engineering and a topic of passionate debate. In this article, we’ll dive deep into the TTB suspension. I’ll cover its history, how it works, its pros and cons, alignment procedures, and other key considerations.

History of the Twin Traction Beam Suspension

Ford introduced the Twin Traction Beam suspension 1980 and it became a defining feature of their 4×4 trucks. The F-Series lineup, including the beloved Bullnose models, employed it for years. Engineers designed it as a compromise between the ruggedness of a solid axle and the comfort of independent suspension. The TTB was Ford’s answer to the demand for a versatile suspension system that could handle both on-road comfort and off-road capability.

Ford used the TTB suspension in various vehicles, notably in the F-150 and F-250 4×4 trucks, as well as the Ford Bronco. This system remained in production through the mid-1990s, though its design evolved over the years. Enthusiasts often recognize the TTB for its unique design and the specific handling characteristics it imparts to trucks.

How the Twin Traction Beam Suspension Works

At its core, the TTB is an independent front suspension (IFS) system designed specifically for 4×4 vehicles. Unlike a traditional solid axle, where both wheels are connected by a single rigid beam, the TTB uses two independent beams, each attached to its respective wheel. Here’s a breakdown of how it works:

Beams and Pivot Points: The TTB suspension utilizes two beams, each pivoting near the center of the vehicle on the crossmember. These beams extend outward to the wheels, allowing them to move independently.
Differential Placement: The differential is mounted on one of the beams, typically the passenger side. The driver’s side uses A slip-joint axle to allow for the independent movement of the wheels.
Spring and Shock Absorption: The TTB typically uses coil springs in the front (in some models) and leaf springs in the rear. This can vary though depending on the specific vehicle model and year. Shocks are mounted to help dampen the suspension’s movement, contributing to a smoother ride.
Steering and Camber Changes: As the wheels move up and down over uneven terrain, the camber angle of the wheels changes. This can affect tire wear and handling. This is one of the unique characteristics—and challenges—of the TTB design.

The resultant suspension system allows for greater wheel travel and better off-road performance compared to a traditional solid axle. However, this comes with its own set of complexities, particularly when it comes to alignment and maintenance.

Specifications of the TTB Suspension

The specific components and dimensions of the TTB suspension can vary slightly depending on the vehicle model and year. However, here are some general specifications you might find in a Bullnose-era Ford truck:

Beam Material: Typically made from stamped steel for durability and strength.
Axle Shafts: Often made from high-strength steel, designed to withstand the torque generated by the engine.
Differential: Mounted on one of the beams, usually the passenger side, and connected to the driver’s side via a slip-joint axle.
Wheel Travel: Varies depending on the model, but generally provides more travel than a solid axle, improving off-road capability.
Camber Angle Variation: One of the challenges of the TTB, the camber can change significantly as the suspension moves, requiring careful alignment.

Pros and Cons of the TTB Suspension

Like any suspension system, the TTB has its strengths and weaknesses. Debate continues among enthusiasts and off-roaders.

Pros:

Improved Off-Road Capability: The TTB’s independent nature allows for better wheel articulation. This makes it more capable on rough terrain compared to a solid axle.
Ruggedness: Designed to handle the stress of off-roading, the TTB is tough and durable. Engineers built many components to withstand heavy use.
Better Ride Comfort: Compared to a solid axle, the TTB provides a smoother ride on uneven surfaces. This contributes to making it more comfortable for daily driving.

Cons:

Complex Alignment: Due to the camber changes that occur as the suspension moves, aligning a TTB-equipped vehicle can be tricky. It requires precise adjustments to ensure proper tire wear and handling.
Increased Maintenance: The TTB has more moving parts than a solid axle, which means there are more components that can wear out or require maintenance.
Weight: The TTB suspension is heavier than some other IFS designs, which can affect fuel economy and overall vehicle weight.

Vehicles Equipped with TTB Suspension

The TTB suspension was primarily used in Ford’s F-Series trucks and the Ford Bronco during the 1980s and 1990s. Here are some of the specific models where you’ll find this suspension:

Ford F-150 (1980-1996): The TTB was used in 4×4 models, making it a popular choice for off-road enthusiasts.
Ford F-250 (1980-1996): The heavier-duty F-250 also utilized the TTB in its 4×4 models, offering a balance of ruggedness and comfort.
Ford Bronco (1980-1996): The TTB was a key feature in the Bronco, contributing to its legendary off-road reputation.

These vehicles, particularly the Bullnose models (1980-1986), are highly sought after by collectors and off-roaders alike, in no small part due to the TTB suspension.

Vehicle	Years Equipped	Notes/Changes
Ford F-150	1980 – 1996 (4WD models)	Used in 4WD models, typically with the Dana 44 TTB setup. Replaced by IFS in 1997.
Ford F-250	1980 – 1997 (4WD models)	Primarily used Dana 50 TTB. Phased out by 1999 in favor of solid Dana 60 axles in Super Duty models.
Ford Bronco	1980 – 1996	Standard in 4WD models, providing better ride comfort and off-road performance than solid axles.
Ford Ranger	1983 – 1997 (4WD models)	The Ranger featured a lighter-duty TTB system compared to larger trucks.
Ford Explorer	1991 – 1994 (4WD models)	Early 4WD Explorers used TTB before switching to independent front suspension.

How to Align the Twin Ttraction Beam Suspension

Aligning a TTB suspension is more involved than aligning a traditional solid axle. This is primarily due to the changes in camber that occur as the suspension moves. Proper alignment is crucial not only for handling but also for preventing uneven tire wear. Here’s a general guide to aligning a TTB suspension:

Start with the Basics: Ensure that all suspension components are in good condition. Worn-out ball joints, bushings, or shocks can make proper alignment impossible.
Set the Ride Height: The ride height affects camber, so it’s important to set it to factory specifications before attempting alignment. This may involve adjusting the torsion bars (if applicable) or ensuring the springs are properly seated.
Check and Adjust Camber: Using a camber gauge, measure the camber angle. On a TTB suspension, this angle can change as the suspension moves, so it’s important to take measurements at the ride height. Adjust the camber by shimming the spindle as needed.
Adjust Caster: Caster adjustment is also important for handling. This is usually adjusted by shimming the radius arm or using adjustable bushings. Ensure that both sides are adjusted evenly.
Set Toe: Toe adjustment is critical for tire wear. Use a toe gauge to measure and adjust the toe to factory specifications. This is typically the last step in the alignment process.
Test Drive and Recheck: After making all adjustments, take the vehicle for a test drive to ensure it handles correctly. Recheck the alignment to make sure everything is within spec.

It’s worth noting that due to the complexity of the TTB suspension, many owners opt to have their alignments done by a professional. It’s important to find one that has familiarity with this setup… they’re getting harder to find!

Differences Between the Twin Traction Beam (TTB) and Twin I-Beam Suspensions

Ford introduced both the Twin I-Beam and Twin Traction Beam (TTB) suspensions as innovations aimed at improving ride comfort and off-road capability, but they have distinct differences that cater to different driving needs.

Twin I-Beam Suspension

The Twin I-Beam suspension was first introduced by Ford in 1965 and became a staple in their 2WD trucks. Here’s how it works:

Design: The Twin I-Beam uses two independent beams, each attached to the frame at one end and to a spindle at the other, allowing each wheel to move independently. This design is intended to offer a smoother ride over uneven terrain, as each wheel can respond to bumps and dips separately.
Use Case: Primarily found in 2WD trucks, the Twin I-Beam is known for its durability and ability to handle rough roads, though it has a reputation for causing tire wear due to changes in camber as the suspension cycles through its travel.
Advantages: Provides a smooth ride on uneven surfaces, rugged and durable, simpler and lighter than TTB.
Challenges: Difficulties in maintaining proper alignment due to camber changes, especially as the suspension ages.

Twin Traction Beam (TTB) Suspension

The Twin Traction Beam (TTB) suspension, introduced in 1980, was Ford’s solution for their 4×4 trucks, designed to offer the benefits of independent front suspension while maintaining off-road durability.

Design: The TTB is essentially an evolution of the Twin I-Beam. The key difference is that it includes a differential and is designed for 4WD vehicles. The TTB allows each wheel to move independently, but one beam is mounted to the differential, which is then connected to the other beam through a slip-joint axle.
Use Case: Found in 4×4 trucks and the Ford Bronco, the TTB is designed for off-road capability while providing a smoother ride than a solid axle. It maintains independent movement for each wheel, which helps in navigating rough terrain.
Advantages: Greater wheel travel and off-road capability compared to the Twin I-Beam, better suited for 4WD applications, and improved ride comfort compared to a solid axle.
Challenges: More complex alignment procedures due to camber changes, heavier and more maintenance-intensive than the Twin I-Beam.

Key Differences

Application: The Twin I-Beam is primarily used in 2WD trucks, whereas the TTB is designed for 4×4 vehicles.
Differential Integration: The TTB integrates a differential for 4WD capability, which the Twin I-Beam lacks.
Off-Road Capability: The TTB offers better off-road performance due to its design. The Twin I-Beam focuses more on ride comfort in 2WD setups.
Maintenance and Alignment: The TTB is more complex to maintain and align compared to the simpler Twin I-Beam, though both can experience issues with camber changes.

In summary, while both suspensions share the concept of independent front wheel movement, the Twin I-Beam is more suited for 2WD trucks with an emphasis on ride comfort, whereas the TTB is tailored for 4×4 trucks, providing a balance between off-road capability and ride quality.

Other Considerations for the TTB Suspension

When working with a TTB suspension, there are a few additional considerations to keep in mind:

Lift Kits: Many Bullnose owners choose to lift their trucks for better off-road performance. When lifting a TTB-equipped vehicle, it’s important to use a kit designed specifically for the TTB suspension to avoid issues with camber and steering geometry.
Aftermarket Upgrades: There are various aftermarket upgrades available for the TTB suspension, including stronger axle shafts, upgraded bushings, and custom beams. These can improve the performance and durability of the suspension, particularly in off-road conditions.
Regular Maintenance: The TTB suspension, like any other, requires regular maintenance to perform its best. This includes checking and replacing worn components, ensuring proper lubrication, and performing regular alignments.
Replacement Parts: While TTB parts are generally durable, finding replacement parts can sometimes be challenging, especially for older models. It’s a good idea to source quality parts from reputable suppliers to keep your TTB suspension in top shape.

Conclusion

The Twin Traction Beam (TTB) suspension is a standout feature of Bullnose Ford trucks, known for its blend of rugged off-road capability and on-road comfort. While it does present some challenges, particularly in terms of alignment and maintenance, its engineering and performance make it a favorite among enthusiasts.

Whether you’re restoring a classic Bullnose, upgrading your off-road rig, or maintaining your TTB suspension, understanding this system is crucial. With the right knowledge and care, your TTB-equipped Bullnose truck can continue to deliver the performance and durability that Ford intended.

Whether you’re hitting the trails or cruising down the highway, you can trust your TTB suspension to handle the journey. Understanding its intricacies not only helps in maintaining and enhancing your truck but also deepens your appreciation for these iconic vehicles.

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For more information on Bullnose Trucks and Broncos, you can also check out the BullnoseFord SubReddit or Gary’s Garagemahal, both are excellent resources.