We previously received an inquiry like this:
“When I buy brake pads, the shop staff always tells me to ‘be careful until they bed in.’ That means ‘let the pads and discs seat properly,’ right? But in endurance races, even when they swap out discs and pads, they can’t afford to do a bedding-in process during the race. I see them driving at full throttle immediately after the swap. If that’s the case, isn’t bedding-in actually unnecessary?”
Wow, that is an excellent question.
Let me explain it step-by-step.
Bedding-in is absolutely essential on public roads!
To start with the conclusion, bedding-in new pads is necessary. The reason is that the discs wear down and deform over long-term use. Because of this, when you install new pads, they won’t fit perfectly right away. The period it takes for them to fit perfectly is what we call “bedding-in (seating).”
This holds true even for race cars, but there is a specific reason why bedding-in isn’t necessary in a race.
Why don’t they bed in the brakes in endurance races?
There are two reasons why they don’t bed in the brakes during an endurance race.
- 1. Because they don’t replace the pads.
-
In the first place, they don’t even change the pads during the Suzuka 8 Hours.
Endurance brake pads are extremely thick, so there is no need to replace them during an 8-hour race. - 2. Because the discs are not worn down.
-
In endurance races, the discs are replaced at the same time as the tires.
Strictly speaking, the tire and disc are replaced together as an entire pre-assembled wheel assembly.
Ideally, this replacement cycle happens once every hour.
No matter how many times hard braking is repeated, the discs barely wear down in just about an hour.
Since the replacement discs have the exact same specifications as the previous ones, the seating against the pads remains unchanged.
24時間耐久では？
ル・マンやボルドールの24時間耐久レースとなると、さすがにパッドも交換が必要。
実際は、キャリパーごと交換します。
急にパッドが厚いものに戻るため、フィーリングの変化は当然あります。
でも、ディスクも同時に交換するため、どちらにも編摩耗はありません。
理論的にはスタート時の状態に戻ることになります。
そんなわけで、レース中にアタリ出しは不要ということです。
ただし、全く何もしないわけではありません。
新品のパッドをいきなり本番で使うわけではないです。
練習走行の際に慣らしを行います。
この作業を「焼き入れ」と呼び、通常は2周ほど行います。
新品タイヤの皮むきと似たようなものです。
