The Turner Motorsport Roll Center Correction Race Kit is here to correct your roll center and improve handling, while also providing increased steering response and bump steer correction. Bump steer is also correctable to virtually 0, thanks to spacers to adjust tie rods up or down. Thanks to the use of our rack limiters, you can maintain the same steering angle as before, while drastically decreasing steering wheel input. After the kit was installed on a E36 M3 test vehicle equipped with a Z3 2.7 turn lock to lock steering rack, it only required 2 full turns lock to lock. A reduction of 26%!

When you lower a car with coilovers, it seriously changes the geometry of the suspension. While lowering a car makes it handle better by lowering the center of gravity, the roll center is negatively impacted, increasing the roll moment, which causes cornering forces to have more of an effect on the body roll of the vehicle. This is normally ignored because the stiffer lowering springs make the issue less noticeable, but ultimately grip is lost, and body roll is increased. Once the roll center has been corrected it is immediately apparent how much the performance of the vehicle had been suffering prior.

By correcting the lower outer ball joint location with the Turner Roll Center Correction Race Kit, the instantaneous center of rotation is raised, bringing the roll center much closer to the center of gravity, and significantly decreasing roll movement. This minimizes body roll, provides more grip, and ultimately leads to an improved and predictable driving feel.

Roll Center can be a rather complex concept. Let’s break it down:

On a McPherson front suspension vehicle, both the top of the strut and lower control arm sit at an angle. If you were to draw 2 lines, one from the upper strut mount perpendicular to the steering axis (line through lower ball joint and upper strut mount pivot) and another from the control arm outer and inner ball joint/pivot, Where they intersect is called the instantaneous center of rotation. This is the point about which the suspension is rotating at that instant. Now, noting the vertical center of the car, draw another line from the bottom of the center of the tire contact patch, to the instantaneous center of rotation. Where this line intersects with the vertical center of the car is where your “roll center” is. The distance between the roll center, and the center of gravity is called the “roll moment”. The larger the distance, the larger the body roll. By decreasing the distance between your center of gravity and your roll center, you can decrease the amount of body roll, and decrease suspension geometry change, and ultimately gain better handling.

Features:

• 6061-T6 billet aluminum steering plate
• All specially designed, melonite coated, class 10.9 hardware
• Provides roll center correction for lowered cars (coilovers recommended, lowering springs and replacement shocks generally provide too much droop)
• Provides bump steer correction and adjustment
• Includes ball joint replacements (e36M 027427TMS01~A, E36/46 NM 022961TMS01~A)
• Kitted with high-quality FK rod ends