There are many factors that directly affect the longevity of disc rotors and the safety of the driver when using a high-performance street vehicle on a race track.
The major considerations are listed below:
CORRECT BEDDING OF ROTORS
Generally, experienced drivers will use their track rotors on the street with standard pads for a week or two before any track use. Driving in normal traffic conditions for 200 to 300 km (180 miles) is more effective and less likely to prematurely fatigue the disc rotor material.
If you are unable to utilise this method or prefer the accelerate and brake repetition shortcut, please warm your brakes up first. Drive for at least 1-2 kms (1 mile), with long easy braking. The thermal shock from braking at high speed on cold rotors WILL prematurely fatigue your brakes.
Standard street pads are NOT suitable for track day applications. Core Temperatures of rotors used on track days are generally in the 450ºC to 600ºC (1110ºF) range and peak surface temperatures up to 800ºC (1470ºF) for 5 seconds or more.
Street pads will generally start to break down at 300ºC to 350ºC (570ºF to 660ºF), causing brake pad fade and glazing of the rotor surface. Also the pad structure is degraded resulting in poorer product performance.
WARM UP & COOL DOWN
Disc rotors must be preheated before track sprints to reduce the thermal shock from sudden high speed braking. The greater the difference in rotor temperature from when the pedal is applied to when the pedal is released, is directly proportional to metal fatigue.
This is also applicable after the event, when you exit the track. A cool down lap is advisable at reduced speed with lighter braking to lower the core temperature slowly, or if this is not possible, go for a short drive off the track for a few minutes.
Do not pull up immediately after exiting the track with hot brakes if you plan on using them again!
NOTE : Applying the hand-brake on hot rotors after a track session will distort the rear discs as they cool down.
POST TRACK DAY ROTOR INSPECTION
All disc rotors should be inspected after track day events. This involves removing the rotor from the vehicle and inspecting for heat checking (surface cracking) and severe cracks from fatigue on the pad surfaces. If a suspected crack is found, rub the area with a light grade emery paper, 240 grit or higher, to confirm that it is a crack and not leaching or etching from the pad material.
Pad etching looks similar to light cracking but will disappear with a light rub with emery paper. If the heat checking is advanced to the point where the surface cracks are clearly visible, discard the pair of rotors. One ideal method that should be adopted is to have two sets of rotors.
One set for track use and one for street use. Changing to your street rotors after a track event encourages rotor inspection. Also, your street rotors can become your next track rotors with the advantage of being bedded in gradually. After the initial purchase of two sets of rotors you are still only replacing one set at a time.
MOTORSPORT WARRANTY STATEMENT
DBA’s warranty will NOT apply in relation to use of the product for any form of motorsport or speed trial.
Whilst DBA promotes some of its product for use in motor sport applications, DBA cannot warrant the product when used in any form of motor sport. Vehicle modifications by the consumer are out of our control and may affect the braking requirements for the vehicle and it is the responsibility of the owner to ensure vehicle safety in these applications.
This by no means detracts from the quality of the product DBA manufactures; it simply states that if the product is used in motor sport applications, DBA has no control on how or by whom the product is used.
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