It may sound counter-intuitive but being quick in Formula One isn't just about going fast - stopping well is also a major part of the equation. Montreal's Circuit Gilles Villeneuve features seven braking events in all, of which six are considered to be 'heavy' and four involve braking from over 295 kph.
It amounts to one of the toughest circuits of the year for the brakes. Getting the braking system right for Montreal involves fitting revised air ducts to optimise the cooling, and using different materials to ensure consistent performance for each one of the race's 70 laps. It's no small challenge...
How severe a test is Montreal for the brakes?
The energy input to the brakes is roughly double that measured in Spa. At both circuits, the drivers spend around 15 seconds of the total lap time braking; in Montreal this accounts for 20% of the lap spent on the brakes, while in Spa it only represents 14%.
Where is the heaviest braking event on the circuit?
The biggest single braking event comes at Turn 10, where the cars must slow from 295 kph to just 60 kph for the corner apex. The cars shed 235 kph in a distance of just 140m. When deceleration is at its greatest, the drivers are subjected to peak forces of some 5.5G.
How hard are the drivers working in the cockpit under braking?
The force the drivers exert on the pedal is approximately 2000 newtons - that's equivalent to lifting 200 kg. The theoretical stopping distance of a Formula One car from 300 kph to zero is approximately 135 metres in a straight line, but varies according to drag levels and tyre grip.
What temperatures do the brakes reach?
Peak temperatures during a braking event don't occur when maximum force is applied, but later during the braking phase owing to heat transfer rates. The discs can reach up to 1000°C while caliper temperatures stabilise at around 200°C.
What parts of the braking system are altered for a heavy braking circuit like Montreal?
The thickness and diameter of the brake discs is limited by the regulations to 28mm and 278mm respectively. The brake material - the type of carbon disc and pad - is changed between high and low severity circuits to provide the necessary durability. Large brake ducts are used in order to achieve adequate cooling; these large ducts cost around 0.2s compared to the smallest versions run during the year.
What is a typical brake balance at Montreal?
A typical figure is a front to rear brake force distribution of approximately 55% front/45% rear. However, this changes with KERS, which provides significant torque to the rear axle under braking. This means the drivers must run the brake balance even further forward to prevent the rear tyres from locking.
How will the DRS zones, and the resultant higher straightline speeds, affect the braking demands?
Braking energy inputs will be slightly increased when the DRS is activated. However, this will be highly dependent on how often it is activated during the race, and with what fuel load. Its impact will be greater on higher fuel loads.