BMW Suspension Subframe Mount Kit - Whiteline KDT917

Product Information

A subframe mount bushing (also referred to simply as a subframe mount) is a vibration-isolating bushing used to connect the front and rear subframe to the vehicle’s main body or unibody. The subframe itself serves as a structural framework to mount key assemblies such as the suspension, engine, and transmission. Because the drivetrain and suspension are mounted to the subframe, they naturally transmit vibrations to the body of the car. The subframe mount acts as an additional cushion, absorbing vibrations, shocks, and road noise while allowing some flexibility in the subframe’s movement. This helps reduce stress on the vehicle’s body and provides a smoother, more comfortable ride.

There are a few common types of subframe mounts. In an OE application such as a stock vehicle, the mount is typically made of solid rubber, voided rubber (some holes to increase flexibility), or occasionally hydraulic-filled rubber. In performance and race applications, minimizing movement in the subframe is important to maintain correct suspension geometry during high G-loads, so going to polyurethane mounts or reinforcements is a popular upgrade.

Aging or torn subframe mounts can cause several issues, including poor handling or tracking of the wheels, inability to maintain an alignment with abnormal tire wear, and bangs or clunks when transferring load front to back, like when braking or accelerating. Inspect the mounts for cracks or tears, or leaks if the mount is hydraulic.

• Bangs and Clunks: If you are experiencing clunks or bangs when going over bumps, or when braking or accelerating is a sign that the entire subframe is moving around excessively and the mounts may be bad.
• Increased Vibration (NVH): Subframe mount bushings are designed to isolate vibrations from the engine and suspension. When they go bad, they will not effectively absorb NVH, and you will feel more vibrations transferred to the cabin.
• Handling and alignment issues: Since the suspension is connected to the subframe, the mounts must be in good shape. If they aren't, the suspension will have more freedom of movement independent from the car body/frame, and it may also be difficult to maintain an alignment.
• Excess Movement: With the car securely off the ground, use a lever like a pry bar between the subframe and the body of the car. If there is excess movement and it is easy to shift the subframe, the mounts should be replaced.

About Whiteline

Whiteline is an Australian based performance oriented manufacturer of suspension products that improve the grip, handling and overall performance of your car. Whiteline products include Anti Sway Bars, Chassis Control Bushings, Camber and Toe Kits, Caster Kits, Bump Steer Kits, Strut and Chassis Bracing, and more. Their kits are engineered to work as a system and tested on the race track with a designs that focus on maximum handling with minimal degradation of ride quality.