BMW E60 03-10 (AWD) BC-Racing Coilover Kit [BR-RS] (I-86-RS)
BR Series Street and Circuit Coilover
Pillowball upper mount*
Camber adjustable top mounts*
Aluminium top plates*
30 way adjustable damping
Adjustable spring platform
Height adjustment via bottom mount to retain full damper travel
Bearing mounted upper front spring platform
Dust boot to protect damper seals
* Some features are dependent on model
The BR series coilovers use a large 46mm diameter piston in a 53mm diameter damper body to maximize oil capacity.
As the damper unit operates the oil contained within heats up. The
viscosity of oil changes as its temperature varies which can lead to
changes in the damping characteristic of the unit.
BC Racing only use a very high quality oil with their coilovers but go
that extra mile to maximize performance and build their BR range with a
large 53mm diameter damper body. This increases the capacity of the unit
which increases the volume of oil contained which in turn reduces the
peak temperature and so significantly improves damper performance.
Corner weight adjustment:
The lower spring platform of the BC Racing coilovers are adjustable.
This allows the car to be set up for corner weighting to achieve perfect
balance and ensures that maximum tire efficiency is achieved.
The car needs to be placing equal weight on each tire on an axle so both
front tires need to be taking equal loading as do both rears. This
makes sure that both tires are doing their equal share of work when
cornering which increases overall grip, maximizes corner speed and
reduces lap times.
Optional assister springs can be purchased to allow wheel droop to be dialed into the unit to suit specific needs.
Ride height adjustment
Ride height is determined by the position of the coilover bottom mount.
The mount can be wound up and down the damper body to give a full range
of adjustment from near standard ride height to so low it wouldn’t be
drivable on the road.
Because ride height is determined by an adjustable bottom mount rather
than spring platform you retain full damper travel regardless of the
ride height run.
BR coilovers feature 30 way damping adjustment that combines both
rebound and compression in one adjuster for simplicity and ease of use.
This adjustable facility allows you to fine tune the vehicle to meet the
By tweaking front and rear damping you can adjust the way the car
handles. Increasing damping force on the rear relative to the front, for
example, will start moving the vehicle into a more over steer
If you want to go drag racing in a rear wheel drive car then you want
the back of the car to squat off the line to maximize weight transfer to
the rear and therefore onto the rear tires. This maximizes traction and
helps prevent wheel spin. To achieve this you would soften the rear
dampers to allow faster compression. If you had the rear dampers set to
hard, as you might run the car on a race track, then the car would be
less inclined to squat so traction would be reduced.
Conversely, if you want to go drifting and are finding it hard to break
traction and are having problems with under steer then making the rear
dampers harder will help reduce traction whilst making the front dampers
softer will give greater front traction. This will make the rear of the
car looser whilst minimizing under steer thus altering the vehicles
handling characteristics more towards drift than drag, road or track.
If it’s possible to include camber adjustment on your vehicle then the
BC Racing coilovers automatically include camber adjustable aluminium
pillow ball top mounts. These feature the same high quality Japanese
manufactured pillow ball but give the added benefit of an adjustable top
mount that allows camber to be set to suit your needs be it road, track
The damper units are black chromed steel to give superb durability even
through the darkest of European 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.
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
The springs are compression tested through over 500,000 cycles with less
that 5% deformation.
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 utilize an
innovative and 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 so prevents the common and dangerous problem of the locking collars
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 vehicles 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. It’s vital
that high quality oil is used that can maintain consistent viscosity
under a wide temperature operating range. Once the oil start to degrade,
its properties change leading to damping changes leading to changes in
the vehicles 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 (i.e. whilst out
for a back road blast on or track) 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 go one step further and pressurize 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.
Bearing mounted upper spring platform:
Because the spring twists as it compresses it is very important to
minimise stiction (static friction) 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 pearches 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 un even 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 has a knock on detrimental effect on the vehicles handling
The bearing mounted upper spring platform is one of BC Racings
innovative designs. By vastly reducing stiction 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.
Difference in Series:
The BR-Series is BC-Racing’s latest coilover model with up to date
Depending on your car the coilover kit will have rubber or pillowball
topmounts, or no topmounts at all. For example if you car has double
wishbone suspension it is not needed to use pillow ball mounts and we
advise to use the rubber ones. With double wishbone you also cannot
adjust camber with the front top mounts, so in most cases it would make
no sense to take the more expensive pillow ball top mounts. In some
cases we DO offer the pillow ball mounts as an upgrade, why is that?:
Pillow ball top mount – The applications that come with hardened rubber
top mounts as standard are to ensure the highest quality ride and keep
costs as reasonable as possible for road and track use but we often
offer a pillow ball upgrade for these vehicles should you want to remove
this minimal flex and make the car a little more hardcore. Upgrading to
pillow ball eliminates the flex inherent in even the hardened rubber
used by BC Racing so improving the handling for those looking for the
The product title shows the exact specification of the set, and here is a
list of all possible options you can find in the product title:
BR-RS Series: Front = Rubber Topmount, Rear = Rubber Topmount
BR-RA Series: Front = Pillowball Topmount, Rear = Rubber Topmount or No Topmount
BR-RH Series: Front = Pillowball Topmount, Rear = Pillowball Topmount
BR-RN Series: Front = No Topmount, Rear = Rubber Topmount or No Topmount
Remember: This is not always a specification you can choose but it all
depends on the car’s original suspension technology. We have already
chosen the best suitable option for the average driver based on the
possibilities of the car.