Brake Tech

The myth of warped brake discs


Have you ever heard someone say they had warped brake discs?   Typically someone had the discs resurfaced to cure the problem and after a relatively short time the roughness or vibration came back.

In almost every case, this problem is not caused by a warped discs, but that the brake pad material transferred unevenly to the surface of the disc. This uneven deposition results in thickness variation or run-out due to hot spotting that occurred at elevated temperatures.

Friction is the mechanism that converts dynamic energy into heat.

Read more: The myth of warped brake discs

Main causes of brake fade

Experiencing fading brakes?    Brake fade is a reduction (or total absence) of the stopping power of your brake system that occurs as a result of overheated brake pads.  Simply put, it's when you push on pedal and the vehicle doesn't slow like you planned.  No amount of additional foot pressure can make you stop quicker.  While it is most commonly associated with race cars and heavy trucks that put high demands on the braking system, as you'll read below it can occur on any vehicle that uses friction based deceleration.

We created a PDF report on how to solve brake fade. Get it now.

It's a particularly significant issue compared to other system failures because  once the driver has hit the brakes - they've already committed to the event and there isn't much time to correct when it goes awry.  Brake fade manifests itself with a very firm yet ineffective brake pedal.  So if you're reading this  and your braking issue is not accompanied by a firm or hard brake pedal - you don't have brake fade.  You will need to look deeper for your issue.

 So how do you know if you have brake fade?

          • Your brake pedal is firm (soft pedal is a different condition)
          • Your brakes are not effective.
          • Pumping the brake pedal does not help
          • Once the system has cooled, performance usually returns (although permanently at a reduced effective level as you'll read later!).

How do you solve this?

Read more: Main causes of brake fade

Why use brake cooling


Cooling of the brakes is essential - particularly on 'heavy braking' circuits or events. The heat generated during braking is stored in the discs and must be dissipated by air-flow through and around the disc. Failure to do this will result in reducing brake efficiency and in the extreme, increasing brake pedal travel and loss of retardation. Brake heat is removed by using ducted air directed into the 'eye' of the disc, through the internal vanes - and across the braking faces. It is important to ensure that the heated air escapes from the wheel and wheel-arch - otherwise air-flow is restricted and temperatures will increase. This is very much vehicle specific, there are no general rules.

Read more: Why use brake cooling

Why bleed your brakes

BLEEDING Whilst there is some 'mystery' about this, it is basically a simple operation. The objective is to ensure that all air is purged out of the system(s) so that only good, fresh brake fluid is in the calipers, master cylinders, pipe-work and hoses.

Read more: Why bleed your brakes

Advantage! Alcon Crescent Grooved Rotors

Grooves in the surface of a brake disc for high performance vehicles perform three basic functions:

1) Increases initial friction between the disc and pads, producing more ‘bite’.  2) Continuously refreshes the brake pad surface by removing debris from the pad. 3) Prevents build up of gas from the phenolics within the pads

Traditionally, arrays of long, straight or curved grooves are staggered around the disc surface.  Heat generated during braking leads to thermal distortion of the disc due to the discontinuous friction rubbing surface produced by the grooves, causing reduced pad contact and in some cases brake judder. As a result of dividing the grooves into short segments, the continuous disc surface area is maintained, helping to reduce thermal distortion and hence brake judder.

Read more: Advantage! Alcon Crescent Grooved Rotors

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