High
Performance Car
and Motorcycle Brakes
Good motorcycle
brakes enable you to GO faster and...
Because
they help you STOP faster so...
They
make you RIDE safer...
Do you want
to learn about high performance car and motorcycle
brakes from expert Project Engineer, Honeywell
Aircraft Brian Berk?
Just keep reading and get this INSIDER'S
INFO...
Braking Notes
by Brian Berk ©2002
Modern
racecars and motorcycles need good brakes. Good brakes will
allow you to drive faster. High performance brakes have improved
tremendously over the years with Formula 1 and GT leading the
way using the latest carbon/carbon brake technology. The Formula
One world champion, Mika Hakkinen,
once was quoted saying “The most important thing
in a sports car in not the engine but the brakes”.
Rotor Notes:
•
There are many types of rotors available for racing applications
such as steel, cast iron, carbon/sic, carbon/carbon to
name a few. Rotors can be solid, vented, drilled, or have
slots on the friction surface.
• Cast iron rotors are the most common and readily available
for many applications. Cast Iron rotors should not operate
at a bulk temperature over 610 C and above 3000 rpm.
• Carbon/carbon composite rotors perform well at high
temperatures, much lighter (less rotating weight and unsprung
weight) and are very expensive. Carbon is typically used
in F1, GT and motorcycle brakes, and is showing up more
in drag racing, motorcycle and Champ cars (depending on
regulations).
• Drilled rotors offer improved bite but are more prone
to cracking more so than grooved or solid discs. Rotors
should be discarded of cracks emanate from the mounting
holes, slots, ID or OD. If in doubt, change the rotors
to be safe. It is not worth the risk of a rotor failure
to save a few bucks
• A grooved disc improves cleaning of pad surfaces and
provides more consistent brake performance and longer
life than cross-drilled rotors.
• Runout: With the rotors on the racecar, the runout should
be less than 0.005” |
Brake Pad Notes:
•
Brake pads typically wear more on their leading edges.
High end multi-piston racing calipers have smaller pistons
on the front going to larger pistons on the back of the
caliper to even out brake pad wear.
• Pad break-in or bedding: always break-in according to
the manufactures recommendations. They spend hours testing
on brake dynamometers to develop procedures for bedding
the pads. It is not the best practice to race with new
out of the box pads. |
Fluid Notes:
•
Use a DOT 4 with the highest boiling temperature that
is available. Some race fluids have a boiling temperature
of over 600 F.
• Limit the exposure to the atmosphere. Brake fluid
will absorb water which will lower the boiling point.
With moisture in the fluid the boiling temperature
can be reduced to the 212 –240 F range.
• It is a good practice to flush the brake system
with fresh fluid after a race that required hard braking.
Once the brake fluid has been very hot or near the
boiling point, the boiling point can be lowered. |
Bleeding Notes:
If
time permits, a great way to bleed is gravity
bleeding.
• Open all 4 calipers with master cylinder full
• Use clear tubes off each bleeder into a drain
pan on each caliper
• Bleeders should should be pointed up for this
to work properly
• Watch for bubbles in the tubes. Once there are
no more bubbles, close the bleeders tight. |
Heat Notes:
•
Car and motorcycle brakes convert kinetic energy
to heat. KE=1/2 MV2, or the amount of heat generated
increases by the square of the increase of speed
(V). The faster you go the more heat the brakes
will generate.
• Cast rotors should not operate at a bulk temperature
over 610 C
• Caliper temperatures of car and motorcycle brakes
should be kept well within the working range of
the brake fluid to prevent fluid vaporization
and loss of braking.
• Peak fluid temperatures should not exceed 240
C or operate over 200c for over an hour. Either
case the seals will most likely need replacing.
• Stainless is a good choice for pistons due to
slower heat transfer than mild steels.
• For optimum performance, operate at the correct
brake temperature (refer to manufacture recommendations).
All discs should operate at similar temperatures
front/back and side to side (balance).
• Use temperature paints or stickers to monitor
or investigate rotor, pad or caliper temperatures.
When testing for brake temperatures it is important
to complete several laps in succession (say 10
laps) at race conditions.
• When using ducted air for cooling, most of the
air flow should be directed up the discs vents.
It is important not to overcool, but keep enough
air flow to keep the temperatures stable within
the working range. |
Suppliers
of car and motorcycle brakes:
• Brembo
• AP Racing
• Wilwood
Brian
Berk Project Engineer, Honeywell Aircraft Landing Systems
Article by Brian Berk. Visit http://RacingArticles.com
for more "how-to" on Racing. Don't have time to visit
the site? Subscribe to their Free, monthly newsletter: mailto:join@racingnewsletter.com.
P.S.
Remember to periodically check your car and motorcycle brakes,
especially before the "big" rides. Always ride safely!
:-)
Need new motorcycle brakes?
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Bandit.
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