BC BR Coilovers – Tech 101

Wednesday February 10, 2016

If you’re considering BC BR’s, do yourself a favor and READ THIS POST. There’s a reason you see these on so many builds – including many of our cars here. This post will give you a little insight on what makes these a standout, as well as a detailed look at how you can customize your BR’s with standard and optional features. Basically, if you’ve found yourself here you already know these are great coilovers…now learn WHY.

(…don’t forget we sell these for all makes and models, that’s how we stay in business. You can purchase on our site at the following link BUT if you have tech questions, concerns, don’t see your application, or just want to confirm the setup fits your needs then please drop us an email or call us up. We’re very happy to help!)

Product Page Link: BC Racing Coilovers Page

BC BR’s were a pretty big game changer when they first hit U.S. soil. It was the first versatile, street/occasional track, full-featured & customizable coilover at such a low price point ($995). At the time, the cost put them with the likes of “entry level” kits, but with much more to offer in both quality & function. Fast-forward to today and though the competitive market around BC has changed – along with consumer expectations – BC still continues to be well respected in the industry and a top choice for enthusiasts.

BC also does offer higher cost setups, which target to very specific track/race needs. For the majority of us though, the BR setup is a killer option for our street/occasional track build. BUT if you need things dialed in a bit more specific to your needs, the options are there. Not just for the more basic mods like spring rates, re-valving and swift spring upgrades, but also more advanced options like extreme low (great for stance builds), as well as inverted shocks and external oil reservoirs (great for heavier track use).

Below this point the post is broken down into the BR Coilover “Basic Features” and “Custom & Optional Upgrade” details are found at the bottom.


Damping Adjustment – BC BR Coilovers feature 30-way damping adjustment that combines both rebound and compression in one adjuster for simplicity and ease of use. This allows you to fine tune the vehicle to handle to your liking or to meet the relevant conditions.

Ride Height Adjustment – Ride height is determined by an adjustable bottom mount rather than a spring platform, this allows you to retain full damper travel regardless of the ride height. The mount can be wound up and down the damper body to give a full range of adjustment from near standard ride height down to a 3″ drop and lower (application dependent). For those looking to achieve extreme drop rates it’s important to know that each application has a slightly different MAX drop height. BC BR’s already boast one of the lowest drop rates in the industry BUT for those looking for over a 3″ drop you have the option of getting your kit built out as an “Extreme Low” version. Basically any BC BR Series application can be custom built in an “Extreme Low” version (utilizing shorter spring and shock combo) for extra low drop. This is a FREE service & is explained in more detail in the CUSTOMIZE section of this post.

Aluminum Upper Mounts – All BC Racing BR Coilovers come equipped with aluminum upper mounts. The mount itself is made from aluminum alloy, anodized and then bead blasted to give a high quality, durable finish. A 70A durometer rubber bushing is at the center of the mount in order to achieve the best balance between performance and comfort.

Camber Adjustment Plates – Camber adjustments are added standard into the aluminum top mounts (Front Only) giving the added benefit of setting camber easily to suit your needs. These allow up to an additional 3 degrees of camber adjustment. Please note that this does not take into account the amount of natural camber you gain from simply lowering the vehicle. ****Front camber plates are standard on all kits, so long as the vehicle was equipped with “MacPherson” style front struts from the factory. Camber plates are not applicable with vehicles equipped with “A-Arm” style suspension & would include standard Aluminum Upper Mounts for both front and rear****

KOYO Roller Bearing – Because the spring twists as it compresses it is very important to minimize tension between the spring and its seats. If this tension is not relieved then spring binding can occur leading to the spring rate effectively altering slightly as the spring compresses and extends. The tension generated can lead to rapid deterioration of the spring perches and in extreme cases can cause the spring platform and locking collars to loosen. This can lead to the platform and locking collars ‘walking’ down the damper resulting in uneven ride height and danger of the spring dislocating under full damper extension.

The friction between spring and seats also has an effect on steering effort as the springs are physically turned with the wheels. This introduces additional unnecessary friction into the steering system, which can have a detrimental effect on the vehicles handling characteristics.

The KOYO roller bearing is mounted above the spring just under the upper mount. By vastly reducing tension between the spring and its seats the BC Racing units avoid the above problems thus improving the efficiency of the steering system and allowing the spring and damper to work as designed.

Corrosion protection – The damper units are black chromed steel to give superb durability even through hard winters. The aluminium components (top mounts, locking collars etc) are anodized and the steel lower mounts go through an electrophoretic disposition process followed by powder coating. A random selection of steel components (brackets, dampers, screws etc) are put through a salt spray test once a month to check the quality of the protective processes and that anti corrosive properties are kept at the highest possible standard.

Springs – BC uses linear springs manufactured from SAE9254 high strength durable cold wound steel. The springs are compression tested through over 500,000 cycles with less then 5% deformation.

Patented Lower Lock Collar – BC BR Coilovers use a locking collar to prevent the bottom mount from becoming loose. If the bottom mount becomes loose then the damper body can work its way down into the bottom mount reducing ride height, which can lead to dangerous handling characteristics. BC Racing utilizes a patented designed lower locking collar with a beveled 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 prevents the collars from working loose.

High Quality Oil – 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. As the vehicle travels over rough ground the compression and rebound motion of the damper rod heats the oil. Poor quality dampers use cheap oil whose characteristics alter with varying temperatures. Its vital that high quality oil is used that can maintain consistent viscosity under a wide temperature operating range. Once the oil starts to degrade, its properties change leading to damping changes that can hurt handling characteristics. BC Racing ensures that only high quality oil is used so that damping rates are maintained not only for the moment in hand but that long term longevity is maximized with oil that doesn’t degrade quickly over time thus extending the dampers operating life significantly.

Nitrogen pressurized dampers – When you work a damper hard on track or on high speed bumpy roads you can cause the oil to aerate and cavitation can occur. This causes foaming, which effectively reduces the oils viscosity and so reduces the units damping effect. High quality oil goes a long way to help reduce this problem but BC Racing goes one step further and pressurizes the dampers with nitrogen. The nitrogen exerts a pressure on a floating piston, which in turn exerts a permanent pressure on the oil dramatically reducing aeration and so improving the consistency and quality of the damping. The pressurized nitrogen also adds an additional element of effective spring rate to the damper unit.


Extreme Low – Standard BC BR kits offer a 3″ drop and lower (application dependent). Though this already puts BC as one of the lower standard maximum drop rates in the industry, they also offer an even lower drop “Extreme Low” version. The BC extreme low is a NO CHARGE build option that uses a shorter shock and spring combo to achieve a lower ride height with out compromising ride quality. This option is best suited for users looking for the most aggressive drop rate. Extreme low kits will be built 20-30mm shorter than the standard BR’s. 20mm in the shock body and spring is not the equivalent of 20mm (0.8″) extra vehicle drop height. 20mm may result in an extra 1.5″ drop on some vehicles and could be and extra 2″ on others. Each vehicle responds differently and BC addresses each build accordingly to get the most aggressive drop available for each application. **Using stiffer springs to minimize suspension travel recommended w/ extreme low kits**

Spring Rates & Valving – Each application includes BC’s recommended spring rates for a great balance of ride quality and performance, and is perfect for street driving/occasional track duty. Custom springs are available between 4k and 20k and will be re-valved appropriately. Custom rates are perfect for those looking to tailor their vehicles ride to nearly any purpose (race/drift/stance etc.)

Swift Spring Upgrade – These are linear-rate springs designed for street or competition. Swift’s R & D team created a material called H5S.TW. This advanced alloy is stronger then regular silicone chrome material. Swift made the spring wire thinner, and could wind the springs with fewer coils, which greatly decreased weight while dramatically increasing available stroke. Swift spring rates are available between 4k and 34k and the setup will be valved appropriately.

Damper Adjuster Extenders – These are to help save the time and trouble of removing the interior of your car to change the damper on your rear coilovers. The extenders attach to the adjuster knob on top of your coilover for easy and quick adjustments.


If something wasn’t clear or you have a question on any of the BC BR features or optional upgrades please feel free to reach out to us and a rep will be happy to help you. Post on the comments area of this post, email ([email protected]), or phone in (586-797-9083) for assistance.

One Response to “BC BR Coilovers – Tech 101”

  1. HT

    Awesome info. Thanks for sharing!

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