RIDEFAST AUG 21

DON’T ‘BRAKE’ A SWEAT
A reduction in weight because there’s less material and better
heat dissipation is the main advantages. As with a lot of the
designs we’ve just spoken about, the looks are almost certainly a
factor for these being picked by manufacturers and consumers.
Carbon brake discs:
The most extreme way to approach heat management is opting
for a carbon ceramic setup.
A hot disc means hot pads, and that results in more gas and
debris being released and the brake fluid heating up causing
brake fade. So why not go for a different material?
Carbon discs are much more resistant to heat, and are also less
likely to warp or deform during heavy use, meaning they’ll usually
last longer. As a bonus, they’re typically much lighter than their
counterparts. HOWEVER!! And please take careful note of this:
Other than being prohibitively expensive, they are not meant
for road use EVER!! Carbon discs … and carbon pads for that
matter are extremely heat resistant and require significant heat to
work, hence why you see MotoGP bikes running on normal discs
and pads in wet races. The water cools carbon discs down too
much to be effective.
For road riding, even if you believe yourself to be the fastest
guy down Long Tom pass, you do not generate enough heat to
get them up to operational temperatures and the long bursts
of speed down open roads generates too much wind, cooling
them down too much and too quickly making them completely
ineffective the next time you grab a handful sending you off into
oblivion.
Disc Size matters …
It really does, no matter what your significant other tells you.
Most systems work by converting kinetic energy into thermal
energy (heat) by friction.
On motorcycles, approximately 70% of the braking effort
is performed by the front brake. This, however can vary for
individual motorcycles; longer-wheelbase types having more
weight biased rearward, such as cruisers and tourers, can have a
greater effort applied by the rear brake. In contrast, sports bikes
with a shorter wheelbase and more vertical fork geometry can
tolerate higher front braking loads.
For these reasons, motorcycles tend to have a vastly more
powerful front brake compared to the rear, (Thanks Wikipedia).
The bigger the disc, the stronger the stopping power. The
more pistons, (or pots if you like), on a caliper, the stronger the
stopping power. The more rotors/discs … you guessed it, the
stronger the stopping power.
That is why bigger adventure and road/super bikes have twin
rotors up front ranging in size from about 300mm to around
330mm and sometimes even bigger, usually with multi-pot
calipers and a single smaller rotor with single pot calliper out
back.
Generally most small bikes have a single rotor with single pot
calipers front and rear and in the case of really small bikes those
are sometimes swapped out for drum brakes.
Brake Disc Applications
Calipers …
Single action calipers have brake pistons that operate on one
side only. This type has a floating pin design which allows the
piston side of the calliper to push onto the disc surface and pull
the other side into contact as well.
Dual action, or opposed callipers, are fixed into position to
reduce flex. Dual action have opposed pistons either side of the
disc to greatly improve the piston area.
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Multi piston calipers:
Larger rotors can be used to increase braking force, but this
also increases weight and inertia. To overcome this, brake
manufacturers developed callipers four, six and even eight
pistons.