The Triumph TR6 is a classic British sports car that was produced from 1969 to 1976. It is known for its stylish design, powerful engine, and agile handling. However, one of the TR6’s weaknesses is its rear suspension, which can be prone to roll steer. Roll steer is a condition in which the rear wheels of a car steer in the opposite direction of the front wheels when the car is cornering. This can make the car difficult to control, especially at high speeds.
There are several ways to improve the TR6’s rear suspension roll steer. One way is to install a stiffer rear sway bar. A sway bar is a metal bar that connects the left and right sides of a car’s suspension. It helps to reduce body roll by transferring weight from one side of the car to the other when it is cornering. A stiffer sway bar will reduce the amount of roll steer by preventing the rear wheels from moving independently of the front wheels.
Another way to improve the TR6’s rear suspension roll steer is to install adjustable camber plates. Camber plates are metal plates that are installed between the top of the rear suspension and the body of the car. They allow you to adjust the camber of the rear wheels, which is the angle at which they are tilted in relation to the ground. Adjusting the camber of the rear wheels can help to reduce roll steer by ensuring that the wheels are making contact with the ground evenly when the car is cornering.
Understanding Rear Suspension Roll Steer
Rear suspension roll steer refers to the directional change in the rear wheels of a vehicle when the suspension compresses or extends during cornering. It is a critical factor in determining the vehicle’s handling characteristics, particularly under high-performance driving conditions.
Factors Influencing Rear Suspension Roll Steer
Numerous factors contribute to rear suspension roll steer, including:
| Factor | Effect on Roll Steer | |
|---|---|---|
| Camber Curve | A positive camber curve (wheels tilt outward under compression) induces positive roll steer, causing the rear end to toe out during cornering. | |
| Toe Angle | A positive toe angle (wheels point inward) in the rear suspension results in negative roll steer, causing the rear end to toe in during cornering. | |
| Suspension Geometry | The specific design and geometry of the suspension components also influence roll steer characteristics. For example, a multi-link suspension system can provide greater control and stability over roll steer compared to a solid axle. | |
| Tire Performance | Tire characteristics, such as stiffness, sidewall flexibility, and contact patch size, can affect the vehicle’s roll steer behavior. |
| Link Position | Length (inches) | Roll Steer Effect |
|---|---|---|
| Front Lateral Link | 14.5 – 15 | Neutral to slight understeer |
| Rear Lateral Link | 14 – 14.5 | Stable, reduced oversteer |
Note that these values are just starting points and may need to be adjusted based on the specific track conditions and desired handling characteristics.
Tuning Panhard Bar Alignment
The Panhard bar is a critical component in the Triumph TR6 rear suspension. It is responsible for keeping the rear axle centered under the car and preventing it from shifting side-to-side. When the Panhard bar is not properly aligned, it can cause the rear tires to lose traction and the car to handle poorly.
To align the Panhard bar, you will need the following tools:
- A level
- A tape measure
- A jack
- A jack stand
- A large wrench
First, you will need to place the car on a level surface. Then, you will need to jack up the rear of the car and place it on jack stands.
Once the car is safely supported, you can begin measuring the distance between the Panhard bar and the frame. The distance should be the same on both sides of the car. If it is not, you will need to adjust the Panhard bar length so that the distance is equal on both sides.
Once the Panhard bar length is adjusted, you will need to make sure that the bar is level. To do this, you will need to use the level and place it on the Panhard bar. The bubble in the level should be centered. If it is not, you will need to adjust the Panhard bar height so that the bar is level.
Once the Panhard bar is level, you can tighten the bolts that hold it in place. You should now have the Panhard bar properly aligned.
| Symptom | Cause | Solution |
|---|---|---|
| The car pulls to one side when braking | The Panhard bar is not properly aligned | Adjust the Panhard bar length and height as needed |
| The rear tires lose traction when cornering | The Panhard bar is not properly aligned | Adjust the Panhard bar length and height as needed |
| The car feels unstable when driving over bumps | The Panhard bar is not properly aligned | Adjust the Panhard bar length and height as needed |
Installing Roll Center Adjusters
Roll center adjusters are one of the most effective ways to improve the rear suspension roll steer of a TR6. They allow you to adjust the height of the roll center, which in turn affects the amount of camber change that occurs during suspension travel. This can be used to reduce or eliminate understeer or oversteer, and to improve overall handling balance.
There are several different types of roll center adjusters available for the TR6. Some of the most popular include:
Adjustable upper control arms: These allow you to adjust the height of the roll center by changing the length of the upper control arms.
Adjustable lower control arms: These allow you to adjust the height of the roll center by changing the length of the lower control arms. They are sometimes sold with adjustable upper control arms as a complete kit, which is commonly known as a Z-Link suspension kit.
Adjustable trailing arms: These adjusters fit into the front or rear pivot point of the trailing arm and allow you to adjust the height of the roll center relative to the normal trailing arm. They are designed to correct geometry issues of a lowered car.
These are just a few of the different types of roll center adjusters available for the TR6. When choosing a set of adjusters, it is important to consider your specific needs and goals. If you are not sure which type of adjusters are right for you, it is best to consult with a suspension expert.
Once you have installed your roll center adjusters, you will need to adjust them to the correct height. This can be done by measuring the distance from the ground to the roll center. The ideal height for the roll center will vary depending on the specific suspension setup of your car. However, a good starting point is to set the roll center to be about 1 inch (25mm) below the ground.
Once you have adjusted your roll center adjusters, you should test drive your car to see how they have affected the handling. If you are not happy with the results, you can adjust the height of the roll center again until you find a setting that you are happy with.
Benefits of Installing Roll Center Adjusters
- Reduced understeer or oversteer
- Improved overall handling balance
- Lowered roll center, which can reduce body roll
- Adjustable, allowing for fine-tuning to suit your specific needs
- Compatible with most TR6 suspension setups
Utilizing a Torque Arm to Resist Axle Roll
The torque arm is a critical component in controlling rear suspension roll steer. By connecting the rear axle to the chassis, it acts as a lever arm to resist the axle’s twisting force during acceleration or braking. This reduces the amount of roll steer that occurs, resulting in improved handling and stability.
Types of Torque Arms
There are two main types of torque arms:
- Lower Torque Arm: Mounts on the rear axle housing and connects to the chassis or subframe.
- Upper Torque Arm: Mounts on the rear axle housing and connects to the body of the vehicle.
Installation Considerations
When installing a torque arm, several factors must be taken into account:
| Characteristic | Impact | Considerations |
|---|---|---|
| Mount Location | Affects the angle and leverage of the torque arm | Choose a mounting point that provides sufficient leverage and minimizes binding. |
| Arm Length | Determines the amount of leverage | Select an arm length that provides the desired level of roll control without causing excessive binding. |
| Bushings | Absorb vibration and allow for movement | Use high-quality bushings that will withstand the forces imposed during driving. |
Benefits of a Torque Arm
Installing a torque arm provides numerous benefits, including:
- Reduced roll steer
- Improved handling and stability
- Enhanced traction during acceleration and braking
- Increased durability of the rear suspension
Installing Trailing Arms for Improved Roll Control
Trailing arms are an effective solution to reducing roll steer in the Triumph TR6. They work by providing a more positive connection between the suspension and the chassis, eliminating the tendency for the rear wheels to toe-out under load.
Fabrication and Installation
Fabricating and installing trailing arms for the TR6 involves the following steps:
- Design and fabricate the trailing arms using materials such as steel or aluminum.
- Weld the trailing arms to the rear axle housing.
- Attach the leading end of the trailing arms to the chassis frame using brackets or mounting points.
- Install new shock absorbers and springs.
- Adjust the length of the trailing arms to achieve the desired roll stiffness.
- Test drive the vehicle and make any necessary adjustments.
- Have the alignment checked and adjusted as needed.
- Enjoy the improved handling and reduced roll steer of your Triumph TR6.
Benefits
Installing trailing arms offers several benefits:
- Reduced roll steer
- Improved handling
- Increased stability
- Enhanced driving experience
Upgrading to a Watts Linkage
Installing a Watts linkage is one of the most effective ways to improve the rear suspension roll steer of a TR6. A Watts linkage is a four-bar linkage that connects the rear axle to the chassis. It prevents the axle from moving sideways relative to the chassis, which eliminates roll steer.
There are several benefits to installing a Watts linkage. First, it improves handling by reducing understeer and improving cornering stability. Second, it reduces tire wear by preventing the tires from scrubbing against the fenders. Third, it makes the car more comfortable to drive by reducing road noise and vibration.
Installing a Watts linkage is a relatively straightforward process. However, it is important to make sure that the linkage is properly installed and adjusted. If the linkage is not installed correctly, it can actually make the handling of the car worse.
Here are the steps involved in installing a Watts linkage:
- Remove the rear axle from the car.
- Install the Watts linkage brackets to the chassis and axle.
- Connect the Watts linkage to the brackets.
- Adjust the length of the Watts linkage so that the axle is centered in the chassis.
- Install the rear axle back into the car.
Once the Watts linkage is installed, it is important to check the alignment of the car. This will ensure that the car is handling properly.
Installing a Watts linkage is a great way to improve the handling and performance of a TR6. It is a relatively inexpensive and easy-to-install modification that can make a significant difference in the way the car drives.
Parts List
The following parts are required to install a Watts linkage on a TR6:
| Part | Quantity |
|---|---|
| Watts linkage | 1 |
| Watts linkage brackets | 4 |
| Bolts | 8 |
| Nuts | 8 |
| Washers | 16 |
Fine-tuning with Adjustable Shock Valving
Adjustable shock valves allow you to fine-tune the suspension response for optimal roll steer characteristics. Adjust the following settings:
1. Bump Damping
Increase bump damping to reduce body roll and increase rear traction. Stiffer bump damping limits shock travel, minimizing squat and lateral movement.
2. Rebound Damping
Decrease rebound damping to allow the rear wheels to “fall” into corners quicker. This promotes more aggressive corner entry and reduces understeer.
3. Ride Height
Lower the rear ride height slightly to increase roll stiffness and reduce lateral movement. This shifts the weight distribution towards the rear, improving traction.
4. Toe Angle
Adjust the toe angle slightly outward to create a slight “toe-out” angle. This helps the rear wheels to rotate more freely when cornering, reducing understeer.
5. Lateral Dampening Plate
Install a lateral dampening plate to reduce lateral movement and improve rear stability. The plate creates a dampening effect between the rear axle and subframe.
6. Rear Anti-Roll Bar
Increase the stiffness of the rear anti-roll bar to reduce body roll and improve cornering grip. A stiffer bar distributes more load to the outside wheel, increasing traction.
7. Rear Suspension Bushings
Upgrade to stiffer suspension bushings to reduce lateral movement and improve handling precision. Stiffer bushings provide better control over rear wheel placement.
8. Rear Subframe Mount Reinforcement
Reinforce the rear subframe mount points to increase chassis rigidity. Stronger mounts reduce flex and improve overall suspension performance.
9. Roll Center Adjustment
Adjust the rear roll center by lowering or raising the suspension pickup points. Lowering the roll center increases anti-roll bar effectiveness.
10. Shock Fluid Viscosity
Experiment with different shock fluid viscosities to find the ideal balance of roll stiffness and traction. Thicker fluids provide more damping and control, while thinner fluids allow for more freedom of movement. Consider using a combination of fluids with different viscosities to achieve optimal results. Selecting the appropriate fluid viscosity for your specific vehicle and driving conditions will maximize the effectiveness of your adjustable shock valving.
How To Improve The Tr6 Rear Suspension Roll Steer
The TR6 is a classic British sports car that is known for its handling and performance. However, the rear suspension on the TR6 can be prone to roll steer, which can make the car difficult to control at high speeds. There are a few things that can be done to improve the TR6 rear suspension roll steer, including:
- Installing a stiffer rear sway bar. A stiffer rear sway bar will help to reduce body roll, which will in turn reduce roll steer.
- Upgrading the rear shocks. Upgrading the rear shocks to a set of performance shocks will help to improve the damping of the suspension, which will also reduce roll steer.
- Installing a rear strut tower brace. A rear strut tower brace will help to stiffen the rear of the car, which will also reduce roll steer.
People Also Ask
How does roll steer affect the handling of a car?
Roll steer is the tendency of a car’s rear wheels to steer in the opposite direction of the front wheels when the car is cornering. This can make the car difficult to control at high speeds, as it can cause the car to oversteer or understeer.
What are the symptoms of roll steer?
The symptoms of roll steer include:
- The car feels unstable at high speeds.
- The car oversteers or understeers when cornering.
- The rear wheels seem to “squirm” when the car is cornering.
How can I fix roll steer?
There are a few things that can be done to fix roll steer, including:
- Installing a stiffer rear sway bar.
- Upgrading the rear shocks.
- Installing a rear strut tower brace.
