How an F1 Clutch Works | F1 Engineering

Main ideas / lessons conveyed

• Purpose of an F1 clutch

  • The clutch transmits drive from the engine to the gearbox, which then sends power through the differential (diff) to the wheels.
  • It separates the engine from the drivetrain so the engine can run while the car remains stationary (e.g., on the grid or at race start conditions).
  • When engaged, it connects the engine to the drivetrain to launch the car forward from a standing start.

• When the clutch is used

  • It is not used for gear changes.
  • It is used primarily:
    • At the start of a race (and when leaving the pit lane / pulling away from the pit lane).
    • When the car stops (so the drivetrain is disengaged again).

• Clutch suppliers, cost, and size/weight

  • F1 clutches are made by two manufacturers:
    • AP Racing
    • Sachs
  • Typical cost: ~£6,000 (about $7,500).
  • Weight example given: just under 1.4 kg.
  • Clutch plate diameters:
    • Older example: 115 mm
    • Compared reference: a Ford Mondeo clutch 5.2 kg, 240 mm diameter
    • Newer F1 clutches: 97 mm diameter

• Operating conditions

  • At track/race starts, clutch plates can reach up to ~500°C.
  • Despite high performance requirements, the internal mechanics are described as relatively simple.

• Clutch location on the car

  • The car has a monocoque/tub with the driver seated.
  • The engine is behind the driver and bolted to the monocoque.
  • The gearbox is bolted to the engine and connected to rear suspension components.
  • The clutch is located on the back of the engine, just in front of the gearbox, where it “breaks drive” between engine and gears.

How the clutch works (detailed mechanism)

• Major parts shown/described

  • Basket (yellow parts mentioned)
    • Made out of titanium
    • Holds/retains the clutch plates
  • Diaphragm spring
    • Has fingers that react to pressure
  • Shim
    • A spacer used to compensate for wear
  • Clutch plates
    • Driver clutch plate (described as having fingers on the end)
    • Driven clutch plate
    • Names explained later conceptually (in the video’s flow)
  • Slave cylinder
    • Actuated by hydraulic pressure controlled by the car’s electronics

• Engine-to-gearbox separation (“disengaged” state)

  • The basket is connected to the engine’s flywheel and spins with the crankshaft.
  • The basket’s internal assembly is connected to the gearbox via a shaft.
  • When the clutch plates are separated, the engine can spin the basket, while the gearbox does not turn—allowing the car to stay still.

• Hydraulic actuation by the driver

  • Driver presses the clutch pedal (on the steering wheel area).
  • The electronics determine pedal position and send control through a Moog valve.
  • That valve adds hydraulic pressure to the slave cylinder.
  • The slave cylinder pushes a moving piston/ring assembly into the clutch system.

• Engaging the clutch (“connected” state)

  • When the slave cylinder pushes:
    • It contacts/loads the diaphragm spring.
    • The diaphragm spring fingers are forced in such a way that it opens/adjusts the internal ring.
    • This creates more space when the clutch is disengaged, and reduces space when the clutch is released/engaged (as described in the text flow).
  • Once the fingers/spring return to the engaged condition:
    • The clutch plates grip together
    • Load transfers from engine → clutch plates → gearbox

Wear, slip, and how teams manage it

• Why clutch wear happens

  • With repeated engagement, heat and friction cause the clutch plates to wear over time.

• What goes wrong when worn

  • When plates don’t grip properly, it can cause clutch slip.
  • Effects of slip:
    • Drive doesn’t transfer fully from engine to gearbox
    • Car becomes slower
    • Clutch can heat up quickly
    • Can destroy itself rapidly if slipping persistently

• How the team prevents failure

  • Teams constantly check clutch plate wear by measuring stack height to a very precise size.
  • As plates wear and the stack height decreases, they compensate using a shim:
    • Shim is a titanium spacer of adjustable thickness.
    • Thicker shim over time takes up the lost space so engagement performance and “bite point” remain consistent.

Race-start procedure and driver control (methodology/instructions)

Pre-race / team preparation (described conceptually)

• Arrive at the start with the clutch at the correct operating condition

  • Teams control clutch temperature and bite behavior through:
    • Conventional starts
    • Burnouts
    • A specific number of practice starts
  • These steps are tuned so the clutch temperature and bite point match what the team expects.

• Constraints

  • Clutches (like brakes) can’t be too cold or too hot.
  • Exact temperature affects:
    • The stack/behavior of the carbon plates
    • The bite point, which changes slightly with conditions.

Driver technique at the start (key steps)

• Clutch bite point must be found manually

  • The modern setup uses only one usable clutch paddle for the start, meaning:
    • Drivers must find the bite point manually with their hand
  • Electronic “bite point finding” systems are described as unavailable for this function.

• Twin-part paddle usage (as described)

  • The procedure is:
    • Release the first half of the clutch paddle partway out to achieve the first control stage
    • Then release the second half to complete the engagement for the launch

• Driver’s challenge

  • Small variability is inevitable (“variability” / “jeopardy” described).
  • The difficult part for the driver is finding the bite point precisely while moving through the steering wheel controls.

Steering-wheel geometry and why Ferrari/Hamilton changes matter

• Paddle motion arc affects finger control

  • With a certain pivot position, paddle motion creates:
    • A short paddle travel
    • A larger effective arc of the fingertips when the wheel is turned sideways
    • Finger stretching/sliding risks near the finish of travel

• Ferrari’s steering/wheel pivot change

  • Ferrari reportedly set the clutch pivot so:
    • The driver gets a longer paddle for fingertip actuation
    • The arc of finger movement is reduced
    • It helps drivers apply the “last bit” of movement more precisely on fingertips rather than losing control due to sliding/stretching.

• Observation of adoption

  • The speaker notes Hamilton also tried/used similar ideas, and testing behavior is referenced (e.g., returning to a twin paddle setup during testing).

Sources / speakers mentioned

• Craig Scarborough — described as an F1 technical journalist interviewed for insights on the F1 start process.
• The video narrator/speaker — the primary presenter (unnamed in the subtitles), who demonstrates/explains the clutch and its components.