How Brakes Work And What You May Need

[chopper]

Brake hydraulics are FORCE, PRESSURE, FRICTION and PISTON TRAVEL.
Your engine is not the most powerful part of your motorcycle. It's the brakes.

Consider that brand X motorcycle can do a standing ¼ mile in 10.8 seconds with a terminal speed of 138 mph. The brakes can do the same amount of work in reverse at 6.8 seconds.

A functioning brake system must be closed, full of fluid and leak free. Fluid must not leave and air must not be allowed to enter.


So, hydraulic system laws are as follows:

A. Fluid cannot be compressed to a lesser volume regardless of pressure.

B. Pressure is equal to all surfaces of the containing system.

Hydraulic Principles

The most important brake principles are FORCE, FLUID DISPLACEMENT and LEVER PIVOT POINT.

The fluid is pressurized by the force of a piston. The amount of pressure depends on the amount of force applied to the piston.

Using pistons with different surface areas allows any relationship with force possible.

Now lets talk about FRICTION.

Friction is the resistance to sliding. Two things in contact with and trying to move relative to each other have friction.

The amount of friction depends on the types of surfaces in contact with one another.

In a brake system friction is used to build heat.

Heat stops the motorcycle.

The amount of friction and heat depends on the materials and roughness.

This is why some brake pads are more efficient than others (higher friction) and why drilled disks can be more effective creating stopping power as well as helping displace water to maintain heat in wet conditions.

So, to increase the performance of your brake system you have several options as follows:

One of the simplest and most effective is to change your rubber brake lines to the braided type. This minimizes swell in the hose and will apply more travel to your caliper piston thereby increasing braking power.

You can change your master cylinder to a smaller piston surface area to increase force at the caliper or change the pivot point at the master cylinder in order to apply more force at the master cylinder.

Increasing the caliper piston area ( let's say 4 piston to 6) will apply more pressure to the disc.

Increasing the diameter of the disc will apply the advantage of leverage to the wheel creating more stopping power.

So now after all that tech stuff let's talk about brake fade.

Brake fade mostly occurs after braking very hard several times at high speed.

It can occur gradually or suddenly. Old style drum brakes are much more prone to this then disc.

Three kinds of fade can occur.

1. Pad fade.

Your pads (friction material) get so hot that your friction coefficient drops off to nothing.

2.New pad fade.

You install a new set of pads and start cramming your brakes on hard right off the bat. This does not allow your pads to break in and glazes them over. This can sometimes happen so fast that you will be very surprised that your brakes dont work worth a damn. Not good. Remember to allow your pads to bed in before racing around like a maniac.

3. Fluid boiling

This usually happens after applying your brakes at high speed multiple times or on a long mountain down hills. Altitude can aggravate this problem due to a lower H2O boiling point.. Brake fluid heating up can cause any moisture absorbed by the fluid to boil ,creating bubbles in your brake system decreasing braking pressure (spongy lever action). DOT 4 and lower quality silicone based fluids have a high affinity for absorbing water.


Changing brake fluid during routine maintenance can help prevent this problem.

So these are just some of the things that can effect your braking system. There are lots more we have not even discussed.

In closing thoughts, having brakes that are overly powerful for your bike can be more dangerous than brakes that are adequate.
If your riding style rarely goes over a 100 mph and you are not racing IMHO having dual 13 discs with 6 piston calipers is probably overkill. The finger pressure required to lock up the front wheel is very light and in a panic stop, wet or gravel conditions could be more of a problem than help.

I know, you might learn to operate them safely but I have ridden some on road racing bikes where the front brakes were downright scary.

The most effective and simple way to increase stopping power is to change pads (friction coefficient) and rubber lines too braided (preventing line swell).

If these changes do not meet your needs then go ahead with multi piston calipers and/or larger rotors.

Just use common sense, With brakes feel is everything, Stopping your wheel suddenly can be Disastrous.