How to Select Brake Rotors
by Dave Zeckhausen
should you choose for your vehicle?
offer the quietest operation, lowest dust and longest pad life.
If you have a luxury car that is not driven aggressively, this may be your best
choice. Often used by endurance racers who need to survive a 24-hour race
without a pad change and are willing to give up some performance to achieve
that. Typically these are the lowest cost option. Some premium
products, such as Centric Parts High Carbon rotors, are available with
directional internal cooling vanes (there's a left and a right side part
number), even though the factory rotors may use straight vanes. See
"Which Way? How to properly install plain, slotted or
drilled brake rotors" for more details.
offer improved bite (initial onset of braking) and slightly
higher friction level than smooth rotors. Slots prevent reduction in
friction due to pad outgassing or brake dust trapped between pads and rotors.
Pad coefficient of friction is maintained over the lifetime of the pads, since
slots shave away glaze formation and expose fresh pad surface each time brakes
are applied. Slotted rotors are by far the number one choice for cars used
in competition or open track events. Best choice for heavy trucks and
SUVs, particularly when extra bite is needed for towing. Disadvantages
include slightly reduced pad life, some low frequency rumble and pedal flutter
when braking hard from high speeds. If the slots are improperly machined
all the way to the outside edges, then rotors may develop cracks sooner than
plain or properly slotted rotors.
offer slightly more bite and friction than slotted rotors.
As with slotted rotors, pad coefficient of friction remains consistent over
their lifetime. Wet bite is improved over plain and slotted rotors, so
these may be the best choice for areas with heavy rainfall, like Seattle or
Singapore. Weight is reduced by about 0.2 pounds per rotor, depending on
size and drill pattern. Disadvantages include possible uneven rotor wear,
typically concentric groove formation, although this is mostly an aesthetic
concern. A major disadvantage is accelerated formation and spreading of
cracks under racing conditions. For this reason, drilled rotors should be
avoided for track cars, unless required by the rules. A common piece of
misinformation is that they have lower performance than smooth rotors, due to
reduced surface area and are for looks only. This is false.
Slotted & Drilled rotors
offer a compromise, midway between the benefits of slotted
rotors and drilled rotors. These are fine for street applications, but
should be avoided for track cars. For the first time, slotted & drilled
rotors are starting to appear on some cars as delivered from the factory,
including models from BMW and Mercedes.
2-Piece Floating rotors
consist of an iron "friction ring" assembled with float
hardware to an aluminum hat or mounting bell. These are
available slotted or drilled. 2-Piece rotors offer substantial weight
savings over the 1-piece rotors described above, as much as 10 pounds per rotor,
depending on the specific application. The design allows the outer
friction ring to expand as it's heated, without being constrained by the center
section. This prevents rotor "coning" and subsequent tapered pad wear and
spongy pedal. Because the center section and friction ring are fabricated
from dissimilar materials, conductive heat transfer is reduced, lowering wheel
bearing temperatures dramatically. Outer friction rings may be replaced
when worn, while reusing the center hat, at substantial cost savings.
for more details on the hardware and assembly of StopTech floating rotors.
For track cars, these are absolute best choice and should be used when
available. A disadvantage is significantly higher initial cost. For street
cars driven in high-salt/chemical environments, corrosion between the iron
friction rings, aluminum hats, and float hardware may lead to reduced product
lifetime. This can be mitigated by flushing the brakes with water
frequently or swapping back and forth between "summer" and "winter" brakes.
The rotors described above are the same external dimensions as
the factory rotors on your vehicle now. Zeckhausen Racing carries a range
of rotors from Centric Parts, StopTech Sport, StopTech, and Girodisc. Brake
upgrades with larger rotors and fixed, multi-piston calipers are also available.
Centric Parts Premium rotors are identical in
dimensions and internal vane design to the factory originals. During assembly,
rotors are straddle cut for the most accurate machining, then double disc ground
for optimum parallelism, minimal runout, and near zero thickness variation.
A non-directional finish is applied for better initial pad bedding. All
surfaces, including the hat, are machined and non-swept surfaces are electrostatically coated with a durable, black finish
(unless noted otherwise below) for corrosion protection
and good looks. Finally, all rotors are computer mill balanced to
incredibly tight tolerances. You won't find a better aftermarket replacement rotor
anywhere. Click here for more details.
Parts High Carbon rotors contain an
advanced metallurgy that reduces pad squeal. The proprietary Molybdenum and
Chromium alloy resist rotor cracking during heavy track use or repeat-stop
situations and increases the friction level, improving brake performance and
stopping power. Increased Chromium and Carbon content is also more resistant to
surface oxidation. For some applications, directional internal cooling
vanes are used for improved cooling over the straight-vane factory rotors.
rotors are available for all applications, offering all the advantages of
Centric High Carbon rotors, with the addition of slotting for higher bite and
StopTech Sport rotors are available for
many applications, offering the advantages of Centric Premium rotors, with
the addition of slotting and/or drilling for higher bite and friction.
(Centric Parts is the parent
company of StopTech Sport and StopTech . StopTech Sport and StopTech rotors start as Centric blanks and are machined in the USA by Centric
Parts on computer-controlled milling machines.)
To order rotors, click here:
and locate your vehicle along
the left side of the store page. Or call us Monday - Friday at
(800)222-8893 x1 for help selecting the proper parts.