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WHY DO MY BRAKES SQUEAL?
Brake squeal is simply a high frequency vibration between the brake
pad and rotor, the energy created from this is heard in the form
of sound waves. Typically, this situation is usually encountered
during low to mid energy applications of the brake. It can be caused
by a number of factors;
Glazed pads or rotors (often caused by aerosol brake cleaners)
Inadequate piston retraction within the caliper causing brake drag (old seals).
Miss-aligned caliper (or bracket, as found on single action calipers)
Single Action calipers with bent [floating] pins or inadequate
lubrication of the pins, not allowing the caliper to properly float.
Brake rotors with excessive run-out.
Brake pad backplates warped (often the culprit for spongy levers too…)
Bound up (or bent) forks or miss-aligned wheel centering causing the forks to bind, putting excessive pressure on the caliper and/or
rotor. If
involved in a front end crash, good idea to check run-out on axle
too.
Buildup of road grime and brake dust on the piston seal area
effecting
proper piston retraction. When’s the last time the calipers
were rebuilt?
Racers should do that annually.
Flush the brake fluid thoroughly at least once a year, more
often in humid
climates or if used in severe conditions…it’s cheap
insurance! Old
contaminated fluid diminishes the overall performance potential
of the
brake system and can lead to more expensive problems.
THERE ARE SO MANY COMPOUNDS, WHICH ONE IS RIGHT FOR ME?
There's tremendous variety in pad materials due to continual R&D
and the specialization of motorcycling environments and conditions.
Brake pad requirements at the Blackwater Enduro (a mud fest) are
significantly different than what the custom Harley rider is looking
for and dramatically different from the parameters of World Superbike.
Check out our section on brake pads for a description of materials
and their intended usage.
CAN I USE "RACE COMPOUNDS" ON THE STREET?
In most cases, a conditional yes. All our race pads can be used
on the street by experienced, knowledgeable and highly skilled riders.
Since race compounds are specifically designed for use in extreme
conditions, their main advantage is higher torque values and improved
fade resistance. But this can typically only be fully realized in
conditions where high thermal and inertial loads are encountered
(meaning: when you're really working your brakes hard and really
need them to work...). Ferodo race pads are manufactured in short
run production batches. Combined with a nonstop R&D effort to
improve their performance characteristics means they're generally
more expensive.
WHAT DOES "BEDDING-IN" BRAKE PADS REALLY MEAN?
Much like a new set of pistons and rings in a freshly bored cylinder,
these moving parts need to mate to function properly. Looking at
the ground surface of a new brake pad and rotor [new or used] under
magnification, the surface looks like a bunch of hills and valleys.
Until these parts are mated, only the peaks are making contact.
If you try to use the brakes hard before they bed-in, you run the
risk of over-heating and carbonizing the surface of the pad. This
means performance will suffer dramatically and a glazed surface
will likely result...you'll probably hear your brakes complaining
via a loud annoying brake squeal. Before installing new pads, clean
the brake rotors by using medium grit sandpaper on the pad track
followed by wiping them down with a clean rag and acetone or denatured
alcohol. Allow some time to bed-in your new brakes by following
the manufacturer recommendations and you'll find they'll work much
better.
• Racers: contact us for specifics.
WHAT'S THE DIFFERENCE BETWEEN DOT 5 AND DOT 5.1 BRAKE FLUID?
DOT 5 is a silicone based synthetic fluid originally designed for
use in military and government vehicles where regular maintenance
could be problematic. Although not hygroscopic in the traditional
sense, water molecules will still find their way into your hydraulics
creating globules rather than being suspended as with traditional
DOT 3/4 & 5.1 fluids…the end result is the same: contamination.
DOT 5 Silicone was never intended for serious high performance application.
Harley Davidson uses it I suspect because it won't ruin your paint
if you're all thumbs and miss the toilet a lot. Interesting aside;
HD's sporting wing; Buell, has switched to a higher performance
DOT 4 in all their 2000 models. DOT 5.1, albeit confusing in designation
(thank the D.O.T. for that), is effectively a lighter viscosity
synthetic poly glycol fluid with DOT 4 performance parameters. It
was developed for use in mechanical ABS systems that require a higher
cyclic rate capability.
MY FRIEND TELLS ME CAST IRON BRAKE ROTORS WILL CRACK AND
COME APART, IS THIS TRUE?
Traditional materials and manufacturing methods have kept the door
open to problems associated with thermal stress fracturing or simply
put, cracking. This phenomenon is primarily focused on the use of
gray irons and particularly individual mold casting. That process
creates difficult to control porosity problems during the casting
procedure. Porosity weakens the structure and reliability suffers.
We address this core issue in several areas by spec’ing high
grade Ductile Iron, not Gray iron. Then using a computer controlled
continuous cast process to produce high quality heat treated iron
ingots (giant bars, often referred to as billet). These are then
cut into plates with highly specialized saws and CNC machined. The
rotors are double disk ground to a tight tolerance and finish to
insure flatness and parallelism. This material and method eliminates
porosity, creates a homogenous and consistent grain matrix structure
that is both very stable and very strong.
See Tech Talk: Ductile vs. Gray Iron
WHY SHOULD I CONSIDER CAST IRON BRAKE ROTORS OVER STAINLESS
STEEL?
Over the years, cast iron has proven itself to be an excellent rotor
material providing superior "feel" and producing a higher
coefficient of friction at the friction couple. If you're looking
for genuinely improved performance in terms of both braking power
and modulation, then this is for you. If rain and or high humidity
is the rule and rust potential a concern, you may wish to consider
the alternative in our new AXIS range which is now offered in premium
400 series Stainless Steel as well.
CAN I USE ANY BRAKE PAD MATERIAL ON CAST IRON?
Generally speaking, most organic (semi-metallic) brake pads are
good for use on iron rotors. If in doubt, contact the manufacturer
for details regarding specific use for this application. Ferodo
Platinum, CP911, CP901, 4004F, 3485F, 3410F and I/D450 are all good
for this. Although the various sintered metal pads will perform
quite well, they generally operate at substantially higher interface
temperatures (by as much as 150 degrees [F] at peak). The result
is usually shortened life span of the rotor and as such, sintered
metal pads are universally not recommended unless specifically denoted
otherwise.
Gray Iron rotors: Sintered metal pads ARE NOT RECOMMENDED for
use under any conditions.
Based on extensive dyno testing, results show it is acceptable
to run Ferodo SinterGrip ST pads on BrakeTech Ductile Iron rotors
(dual disc application only; Buell riders should use either Platinum
or CP911 organic pads).
For interested in a more detailed explanation on this issue, click
here for Tech Talk: Sintered vs. Organic
I'VE READ IN ADS THAT"LASER CUTTING" ROTORS IS
BEST, IS THIS TRUE?
Laser cutting is simply a cheaper (read: less expensive) method
of manufacturing in smaller volume. At the Ferodo R&D Facility,
the same method is employed when doing prototype development of
backplate shapes for testing. It's less costly to laser cut than
to produce stamping dies for low volume production or testing.
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