BC Racing HM Coilovers BMW 3 Series Saloon E90 (05-11) 7/10kg.mm

Key Features

• Pillowball top mounts
• Bearing mounted upper spring platform
• Camber adjustable top mounts (depending on model)
• Ride height adjustment separate to spring preload
• 30 way adjustable damping
• Monotube damper design
• Tapered bottom mount locking collar to prevent collar working loose
• Custom spring rates available
• All spare parts available with low lead times
• Dust boot to protect damper seals
• 1 year manufacturer warranty

Which kit is right for you?

Corner Weighting Adjustment

The BC Racing coilovers feature an adjustable lower spring platform, facilitating corner weighting to attain optimal balance and ensure maximum tyre efficiency.

It's crucial for the car to distribute equal weight on each tyre of an axle, ensuring that both front and rear tyres bear identical loads. This ensures that both tyres contribute equally during cornering, thereby enhancing overall grip, maximising cornering speeds, and reducing lap times.

Optional assister springs are available for purchase, enabling adjustment of wheel droop to suit specific requirements.

Ride Height Adjustment

The ride height is determined by the position of the coilover bottom mount. This mount can be adjusted up and down the damper body, providing a complete range of adjustments.

Since the ride height is determined by an adjustable bottom mount rather than the spring platform, you maintain full damper travel regardless of the chosen ride height setting.

Damping Adjustment

BR coilovers offer a 30-way damping adjustment that combines both rebound and compression into one adjuster, ensuring simplicity and ease of use. This adjustable feature allows for fine-tuning the vehicle to suit various conditions.

By adjusting the damping settings for the front and rear, you can alter the car's handling characteristics. For instance, increasing the damping force at the rear compared to the front will transition the vehicle towards a more oversteer-oriented stance.

For drag racing in a rear-wheel-drive car, achieving optimal weight transfer to the rear tyres is crucial for maximum traction and to prevent wheel spin. Softening the rear dampers to allow faster compression facilitates the desired squatting effect at the rear during launch. Conversely, if the rear dampers are set to a firmer setting, as typically done for track use, the car would be less prone to squatting, thus reducing traction.

On the other hand, for drifting purposes where breaking traction is essential and understeer is problematic, stiffening the rear dampers while softening the front ones enhances rear-wheel traction and loosens the rear of the car, minimizing understeer and transitioning the handling characteristics towards drifting rather than drag racing, road driving, or track use.

Pillowball (Rose Joint) Upper Mount

Several BC Racing BR coilovers are equipped with pillowball upper mounts. These mounts are crafted from aluminium alloy, anodised, and bead blasted to provide a robust, high-quality finish.

The pillowballs, manufactured in Japan, are solid, eliminating any flex or play typically associated with standard rubber mounts. This enhances response and handling by ensuring a stable connection.

Camber Adjustment

If your vehicle allows for camber adjustment, BC Racing coilovers automatically incorporate camber-adjustable aluminium pillowball top mounts. These mounts feature the same high-quality Japanese-manufactured pillowball but offer the additional advantage of an adjustable top mount, allowing you to set camber according to your requirements, whether for road, track, or drift applications.

Corrosion Protection

The damper units are coated with black chromed steel to ensure exceptional durability, even in the harshest European winters. Aluminium components, such as top mounts and locking collars, undergo an anodising process, while steel lower mounts undergo an electrophoretic disposition process followed by powder coating.

Regular quality checks are conducted on a random selection of steel components, including brackets, dampers, and screws, through a monthly salt spray test. This ensures that the protective processes maintain their anti-corrosive properties at the highest possible standard.

High Quality Coil Springs

BC Racing coilovers exclusively utilise top-grade steel for their spring production. These springs are crafted from SAE9254 high-strength, durable cold-wound steel.

Each spring undergoes compression testing, enduring over 500,000 cycles with less than 5% deformation.

Patented Concave Lower Locking Collar

Coilovers employ a locking collar to secure the bottom mount and prevent loosening. When the bottom mount loosens, the damper body may descend into it, causing a reduction in ride height for that corner, potentially resulting in hazardous handling traits. This issue is commonly encountered with coilovers in general.

BC Racing employs an innovative and patented lower locking collar design featuring a bevelled edge. This collar securely seats into a corresponding bevel in the coilover bottom mount, significantly increasing the surface area that the locking collar engages with. Consequently, this design effectively prevents the prevalent and dangerous problem of locking collars working loose.

High Quality Oil

BC Racing dampers utilise an advanced shim stack design and premium-quality oil to effectively regulate the compression and rebound speed of the damper rod, even in the most challenging conditions.

During travel over rough terrain, the motion of the damper rod in compression and rebound heats the oil. Lower-quality dampers often utilise inexpensive oil, which can undergo changes in viscosity with fluctuating temperatures. It is crucial to use high-quality oil capable of maintaining consistent viscosity across a broad temperature range. Once the oil begins to degrade, its properties change, resulting in alterations in damping and consequently affecting the vehicle's handling characteristics.

BC Racing ensures the use of only top-quality oil to maintain consistent damping rates not only during immediate usage (such as spirited driving on back roads or on the track) but also to maximise long-term durability. By utilising oil that resists quick degradation over time, the operating life of the dampers is significantly extended.

Nitrogen Pressurised Dampers

When dampers undergo strenuous usage on the track or on high-speed bumpy roads, it can lead to oil aeration and cavitation. This process results in foaming, effectively reducing the oil's viscosity and thus diminishing the damping effect of the unit. While high-quality oil helps alleviate this issue, BC Racing takes an additional step by pressurising the dampers with nitrogen.

The nitrogen applies pressure on a floating piston, which in turn exerts a constant pressure on the oil, significantly reducing aeration and thereby enhancing the consistency and quality of damping. Additionally, the pressurised nitrogen contributes an extra element of effective spring rate to the damper unit.

Bearing Mounted Upper Spring Platform

Minimising stiction between the spring and its seats is crucial because the spring twists as it compresses. If this tension isn't relieved, spring binding may occur, resulting in a slight alteration in the spring rate as it compresses and extends. This tension can cause rapid deterioration of the spring perches and, in extreme cases, may lead to the loosening of the spring platform and locking collars. Consequently, the platform and locking collars may shift down the damper, causing uneven ride height and posing a risk of the spring dislocating during full damper extension.

Moreover, the friction between the spring and seats affects steering effort as the springs are physically turned with the wheels. This introduces unnecessary friction into the steering system, negatively impacting the vehicle's handling characteristics.

BC Racing's bearing-mounted upper spring platform is one of their innovative designs. By significantly reducing stiction between the spring and its seats, BC Racing units avoid the aforementioned problems, thereby improving the efficiency of the steering system and enabling the spring and damper to function as intended.

Optional Upgrades

Damper adjusting extenders - To save you the hassle of removing the parcel shelf every time you need to adjust the damping on your BC Racing coilovers, we offer pairs of adjuster extenders. These extenders attach to the adjuster knob on the top of the coilover and are available in three lengths: 110mm, 200mm, and 250mm. They can be easily attached in seconds with a simple grub screw design.

Assister spring perch - You may prefer to incorporate some droop with your coilovers, or perhaps you want to modify the ride by adding an additional smaller assister spring. The spring perch and assister springs allow you to do just that. These springs are available in a wide range of spring rates to suit your needs.

Pillowball top mount - Some applications come with hardened rubber top mounts as standard to ensure a high-quality ride and keep costs reasonable for road use. However, we often provide a pillowball upgrade for these vehicles if you wish to eliminate this flex and enhance the car's performance. Upgrading to pillowball eliminates the flex present even in the hardened rubber used by BR Racing, thus improving handling for those seeking the ultimate performance.