Handling Diagnostics

General Straight Line Instability.

- Too much toe-in or toe-out settings.
- Rear toe-out static due to incorrect setting or dynamic due to bump steer setting.
- Low rear down force levels and/ or too much front down force.
- Broken chassis, suspension member or mounting point.

Straight Line Instability: Under Hard Acceleration.

- Worn out or malfunctioning Limited Slip Differential.
- Too little rear toe-out setting.

Straight Line Instability: Car Darts over Bumps.

- Too much toe-in or toe-out setting.
- Uneven front castor setting.
- Uneven front shock forces or bump rubbers.
- Front anti-roll bar set too stiff.

Instability Under Braking: Front end Darts or Wanders.

- Too much front brake bias setting.

Instability Under Braking: Car feels like its going to spin.

- Too much rear positive camber settings and/ or too much rear brake bias setting.

Corner Entry Understeer: Car Struggles to Turn In and is Progressively Worse.

- Braking too hard and too late.
- Insufficient front track width.
- Too stiff front anti-roll bar setting.
- Too soft front anti-roll bar setting.
- Low front roll centre.
- Too low front bump setting.
- Low front down force.
- Too much positive front camber on outside wheel.

Corner Entry Understeer: Car Turn In Good, then Progressively Washes Out.

- Too much front toe-in setting.
- Low front down force.
- Low front camber roll compensation.
- Non linear load transfer, due to roll axis inclination.
- Low front bump or rebound setting.

Corner Entry Understeer: C
Car Turn In Good, then Darts.

- Low front bump or rebound setting.
- Too high front down force levels

Corner Exit Understeer: Slow Corners.

- Excessive corner entry speeds.
- Mid corner throttle application, with understeer present and steering lock applied.
- Adjust driving style to improve throttle application and response.
- Too hight front rebound setting.
- Reduce rear anti-squat setting if present.

Corner Entry Oversteer.

- Broken or locked front anti-roll bar or rear outside shock.
- Interference to rear suspension travel.
- Too stiff rear anti-roll bar or spring rating.
- Loss of rear down force.
- Too much rear toe-in and/or rebound.
- Carrying too much speed into the corner, or lift off oversteer.

Corner Exit Oversteer: Progressively Increasing on Throttle Application.

- Damaged limited slip differential.
- Too soft rear anti-roll bar, spring or shock rating.
- Low rear down force levels.
- Low rear toe-in setting.
- Too much rear camber setting.
- Too stiff anti-roll bar.

Corner Exit Oversteer: Car takes its Set and suddenly breaks loose.

- Too much throttle application.
- Sudden rear outside tyre camber change.
- Lack of rear suspension travel.
- Damaged rear shock.
- Too much rear bump setting.

Too High Front Roll Centre and Too Low Rear Setting.

- Increased rear load transfer resulting in increased oversteer.
- Non linear chassis roll and load transfer.
- Roll axis out of parallel with mass centroid axis.

Too Low Front Roll Centre and Too High Rear Setting.

- Increased front load transfer resulting in increased understeer.
- Non linear chassis roll and load transfer.
- Roll axis out of parallel with mass centroid axis.
- Possible three wheeled motoring on corner exit.

Too Narrow Front Track Width Compared to Rear Track Width.

- Increased understeer in slow and medium corner turn in.
- Increased front track required.

Too Much Spring Rate: General.

- Harsh and choppy ride, hard to put power down on corner exit.
- Sliding and excessive wheel spin on corner exits.

Too Much Spring Rate: Front.

- Turn in understeer, but car may point to apex well.
- Front tyres locks on bumps and may break away.

Too Much Spring Rate: Rear.

- Excessive wheel spin.
- Oversteer on corner exit.

Too Little Spring Rate: General.

- Car prone to bottom out on race track.
- Excessive vertical chassis movement.
- Floating ride feel.
- Unresponsive feel.
- Car may take multiple sets to settle.

Too Little Spring Rate: Front.

- Bottom out under braking loads.
- Car rolls excessively during corners.
- Understeer on turn in.

Too Little Spring Rate: Rear.

- Acceleration squat and increased negative camber.
- Power oversteer tendencies on throttle application.

Too Much Anti-Roll Bar: General.

- Lack of feel with sudden response.
- Prone to slide or skate rather then taking a set.
- Darting over one wheel or diagonal bumps.

Too Much Anti-Roll Bar: Front.

- Increased oversteer tendencies.

Too Much Anti-Roll Bar: Rear.

- Increased corner exit oversteer, hard to put power down with excessive sliding.

To Much Shock: Overall.

- Car does not absorbed road irregularities, but crashes over them.
- Harsh ride with a lots of sliding and sudden changes to ride.

To Much Rebound Setting.

- Wheel can not keep up with road surface changes.
- Inside cornering wheel could be pulled of road by shock.
- Car could become jacked down in long corners (lowered ride height)

To Much Bump Setting

- Initial bump reaction harsh.
- Slow chassis roll.
- Car may jack up in long corners (higher ride height).

Too Little Shock: Overall.

- Floating ride feel.
- Car will oscillate after bumps (bounce along the road).
- Slow and sloppy response.
- Quickly develops chassis roll.

Too Little Rebound Setting.

- Car will oscillate after bumps (bounce along the road).
- Hard to put down power.

Too Little Bump Setting

- Soft bump reaction.
- Car prone to dive or squats, lots of longitudinal weight transfer.
- Lots of car roll, inside front on turn in and outside rear on exit could fall over.

Damaged shock on one corner.

- Hard to identify and isolate.
- If at rear, increased power oversteer and if at front increased understeer in one direction.

Car Feels Heavy and Unresponsive.

- Too much downforce.

Car feels soppy and rolls a lot and is slow to settle in corners.

- Too little damping settings on suspension.
- Too soft anti-roll bar settings (roll resistance) or ride rate.

Car Feels on Edge, Responds too quickly to Inputs with Lack of Feel and wants to Slide all the time.

- Low down force settings.
- Too stiff anti-roll bar settings (roll resistance) or ride rate.
- High shock setting.
- High tyre pressure.

Too Much Tyre Pressure.

- Harsher ride, especially over bumps.
- High temperature in the centre of the tyre.
- Increased tyre wear on centre of tyre.
- Sliding and wheel spin.

Too Little Tyre Pressure.

- Soft ride.
- Unresponsive steering.
- Higher tyre temperature at inside and outside edges.
- Increase wear rates at inside and outside of tyre.
- Reduced overall traction, due to decrease in tyre foot print.

Front Tyres Losing traction.

- Increased understeer tendencies.
- More oversteer needs to be dialled in to the handling balance.
- Anti-roll bar or suspension adjustments needed.

Rear Tyres Losing traction.

- Increased oversteer tendencies.
- More understeer needs to be dialled in to the handling balance.
- Anti-roll bar or suspension adjustments needed.

Too Much Toe-In: Front.

- Car darts over bumps during braking loads and corner entry.
- Hard to turn in on corner entry, if extreme will turn in then wash out.

Too Much Toe-Out: Front.

- Car wanders under braking.
- Unstable in straight lines.
- Reacts to wind gusts, one wheel or diagonal bumps.

Too Much Toe-In: Rear.

- Rear end unstable and light on corner entry.

Too Little Toe-In: Rear.

- Power oversteer on corner exit.

Toe Out: Rear.

- Straight line instability.
- Power oversteer on corner exit.

Too Much Wheel Castor: Front.

- Excessive steering effort required.
- Too much self return action.
- Transmittal of road shocks to steering wheel.

Too Little Wheel Castor: Front.

- Car sensitive to steering effort.
- Lack of steering feel.
- Self return action and feedback reduced.

Uneven Wheel Castor: Front.

- Bias steering response on one side.
- Car prone to swerve on higher castor setting side, on a straight line.

Too Much Negative Camber.

- Increased inside tyre wear.
- Increased heat on inside of tyre.
- Reduced front braking capacity.
- Reduced rear acceleration capacity.

Too Much Positive Camber: Front.

- Increased understeer after turn in on cornering.

Too Much Positive Camber: Rear.

- Increased outside tyre wear.
- Increased heat on outside of tyre.
- If extreme could cause turn in response instability.
- Increased corner exit oversteer.

Too Much toe-in in bump: Front.

- Increased understeer on corner turn in.
- Car darts over bumps.

Too Much toe-out in bump: Front.

- Increase understeer after turn in on corner entry.
- Car wanders under braking.
- Car may dart over one wheel bumps or gusts of wind.

Too Much toe-in in bump: Rear.

- Darting on throttle application on corner exits.
- Roll understeer on corner turn in.
- Rear end instability on corner turn in.

Too Much toe-out in bump: Rear.

- Increased oversteer on power application.
- Similar to static toe-out, to a lesser degree.