Audi R8 LMS 2018, Handbook

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400 – Front Axle, Anti-Roll Bar, Dampers and Steering
Version 1 2016-01-01
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cleaner or similar) in order to avoid contamination during bedding. Normally,
this operation can be avoided because the RB330, 340 & 350 friction material
are initially very abrasive and able to clean up the disc surface automatically,
though time-to-bed will likely increase.
Step 2
The bedding is a very critical determinant of the life of brake components. An
incorrect or hasty procedure could compromise not only the life but also the
performance of components, especially brake discs. The bedding procedure is
needed essentially to prepare the disc for the race, so the processes involved are
the same if it is made on the track (GT, formula, NASCAR, etc.) or on the road
(Rally, where we suggest to bed on tarmac), it changes just the time. In order to
prevent unpredictable heat transfer on disc surface (uneven disc overheating),
and subsequent thermal deformation (cracks, vibrations) the bedding should be
achieved by application of groups of constant pressure stops (for a total of #35-
40 stops or alternatively 35 - 40 km of mileage) with gradually increasing of the
initial speed (and total brake energy). These brakings must be made well below
the tyres’ adhesion limit (50 - 60 % of the max race pedal pressure) in order to
achieve a corresponding gradually increasing of torques and temperature to the
brake system and promote a regular third layer deposit, the brake cooling must
be such to avoid overheating of the system (air ducts can be closed a bit, max 20
%, if disc temperature is too low). The maximum speed should be defined by the
track/road conditions and car features. During this phase the mu starts high
(0,8 – 0,9) and then decreases till the stabilization level, initial discs
temperatures can reach value close to 500 - 550 °C (*) (a bit less for pads, see
graph). Only at the beginning brake dust could be visible as normal consequence
of the initial bedding process. At the first stops, when the mu is still very high
(typical for RB340-RB350) and the disc/pads matching not yet optimized, the
heat transfer on disc could be uneven with small disc areas at high temperature,
despite the low energetic level of the brakings. At the beginning of the bedding
too strong brakings (high deceleration) must then be avoided, that could create