HM Series

Height and Damping adjustable Coilovers

Key Features

30 levels of separate rebound and compression adjustment
Inverted damper design (depending on model)
Dual Piston design (1 reservoir, 1 in shock)
Teflon coated steel braided lines for external reservoir on inverted dampers and solid stem for double A-arm cars
Tapered bottom mount locking collar to prevent it from working loose
Pillowball top mounts
Dust boot to protect the damper seal
Custom spring rates available
All spare parts available with low lead times
1 year manufacturer warranty

Coilover Pages

	BR Series	RM Series	DS series	ER Series	HM Series	ZR Series
Damping adjustability	One-Way	One-Way	One-Way	Two-Way	Two-Way	Three-Way
Inverted Shock Design						When applicable
Linear Valving
Digressive Valving
Custom Spring Rate Option
1-Year Warranty
Individual Components Available

Corner weight adjustment
The adjustable lower spring platform of BC Racing coilovers offers the flexibility to fine-tune the vehicle's setup for corner weighting, achieving an optimal balance and maximizing tire efficiency.
To enhance performance, it's crucial to distribute equal weight on each tire within an axle. This means ensuring both front tires bear equal loads, as well as both rear tires. This balanced distribution ensures that each tire contributes equally during cornering, leading to improved overall grip, heightened cornering speeds, and reduced lap times.
For further customization, optional assister springs are available, allowing for precise adjustment of wheel droop within the unit to meet specific requirements.
Height Adjustment
The ride height is dictated by the placement of the coilover bottom mount, which can be adjusted by winding it up or down the damper body, providing a comprehensive range of customization.
With the ride height being controlled through the adjustable bottom mount rather than the spring platform, you maintain complete damper travel regardless of the chosen ride height setting.
Damping Adjustment
The HM coilovers boast a 30-way damping adjustment that conveniently combines both rebound and compression in a single adjuster for user-friendly simplicity. This adjustable feature empowers you to fine-tune your vehicle to suit specific driving conditions.
Refining the handling of the car can be achieved by adjusting the damping settings for both the front and rear. For instance, increasing the damping force on the rear compared to the front will shift the vehicle toward a more oversteer-oriented stance.

Pillowball (Rose Joint) Upper Mount
Many BC Racing BR Coilovers are equipped with pillowball upper mounts. Constructed from aluminium alloy, the mount undergoes an anodizing process and bead blasting, resulting in a durable and high-quality finish.
These pillowballs, manufactured in Japan, possess a solid composition that eradicates any flex or play typically found in standard rubber mounts. This enhancement contributes to improved response and handling, elevating the overall performance of the coilovers.
Camber Adjustment
If its possible to include camber adjustment on your vehicle then the BC Racing coilovers automatically include camber adjustable aluminium pillowball top mounts. These feature the same high quality Japanese manufactured pillowball but give the added benefit of an adjustable top mount that allows camber to be set to suit your needs be it road, track or drift.
Corrosion Protection
The damper units are crafted from black-chromed steel, ensuring exceptional durability, even in the harshest European winter conditions. Meanwhile, the aluminum components such as top mounts and locking collars undergo an anodizing process, and the steel lower mounts undergo an electrophoretic disposition process followed by powder coating.
To maintain the highest standards of anti-corrosive properties, a random selection of steel components, including brackets, dampers, and screws, undergoes a monthly salt spray test. This rigorous testing procedure ensures the quality of protective processes, confirming that the components meet the highest possible standards for corrosion resistance.

Patented concave lower locking collar
Coilovers use a locking collar to prevent the bottom mount becoming loose. If the bottom mount becomes loose then the damper body can work its way down into the bottom mount so reducing ride height on that one corner which can lead to dangerous handling characteristics. This is a very common problem for coilovers in general.
BC Racing utilise an innovative and patented designed lower locking collar with a bevelled edge that seats into a corresponding bevel in the coilover bottom mount. This vastly increases the surface area that the locking collar works on and so prevents the common and dangerous problem of the locking collars working loose.
High Quality Coil Springs
BC Racing coilovers only use the highest quality steel for their spring manufacturer. They are produced from SAE9254 high strength durable cold wound steel.
The springs are compression tested through over 500,000 cycles with less then 5% deformation.
High quality oil
BC Racing ensures that only high quality oil is used so that damping rates are maintained not only for the moment in hand (i.e. whilst out for a back road blast on or track) but that long term longevity is maximised with oil that doesn’t degrade quickly over time thus extending the dampers operating life significantly.
BC Racing dampers use a sophisticated shim stack design and high quality oil to consistently control the compression and rebound speed of the damper rod even under the most extreme conditions.

Nitrogen Pressurised Dampers
When subjecting a damper to rigorous use, such as on the track or high-speed bumpy roads, the intense activity can lead to oil aeration and the occurrence of cavitation. This process results in foaming, effectively diminishing the oil's viscosity and, consequently, reducing the damping effect of the unit. While high-quality oil goes a long way in mitigating this issue, BC Racing takes an extra step by pressurizing the dampers with nitrogen.
The nitrogen exerts pressure on a floating piston, creating a permanent force on the oil. This significant reduction in aeration improves the consistency and overall quality of damping. Additionally, the pressurized nitrogen introduces an extra element of effective spring rate to the damper unit, further enhancing its performance.
Bearing Mounted Upper Spring Platform
Minimizing stiction between the spring and its seats is crucial because the spring undergoes twisting during compression. Failure to alleviate this tension can result in spring binding, causing a slight alteration in the spring rate as it compresses and extends. The generated tension may lead to rapid wear of the spring perches, and in extreme cases, it can cause the spring platform and locking collars to loosen. This loosening can cause the platform and collars to shift down the damper, resulting in uneven ride height and posing a risk of the spring dislocating during full damper extension.
The friction between the spring and seats also impacts steering effort, as the springs physically turn with the wheels. This introduces unnecessary friction into the steering system, negatively affecting the vehicle's handling characteristics.
BC Racing employs an innovative design with a bearing-mounted upper spring platform to address these issues. By significantly reducing stiction between the spring and its seats, BC Racing units avoid the mentioned problems, improving the efficiency of the steering system and allowing the spring and damper to operate as intended.
Optional Upgrades
Damper adjusting extenders – to save you the time and trouble of removing the parcel shelf each time you want to adjust the damping on your BC Racing coilovers we can offer pairs of adjuster extenders. These attach to the adjuster knob on the top of the coilover and are available in three lengths, 110mm, 200mm and 250mm. They attach in seconds with a simple grub screw design.
Assister spring perch – you might prefer to run some droop with your coilovers or maybe you want to alter the ride by adding an additional smaller assister spring. The spring perch and assister springs allows you to do this. The springs are available in a wide range of spring rates.
Pillowball top mount – some applications come with hardened rubber top mounts as standard to ensure the highest quality ride and keep costs as reasonable as possible for road use but we often offer a pillowball upgrade for these vehicles should you want to remove this flex and make the car a little more hardcore. Upgrading to pillowball eliminates the flex inherent in even the hardened rubber used by BR Racing so improving the handling for those looking for the ultimate.