Vehicle Balance

There are several ways to balance a vehicle to achieve the desired front-to-rear grip levels. Our philosophy, when possible, is to increase grip on the end of the vehicle that has less as opposed to reducing grip on the end that has too much. This approach results in a vehicle with more overall grip.

When applying the changes listed below always begin with the first few adjustments on the list since the later generally have less affect. At a race, try what is easiest first to save time (e.g. Adjust ARB settings).

 

Symptom: Front Understeer (car pushes)

The suggestions below assume that the tire pressures are known, good values for the tires being used on this particular vehicle.

Front Changes: (Begin here first)

  1. Soften front Anti-Roll Bar (switch to holes further away from chassis pivot)
  2. Install lighter front springs
  3. Change tire pressure based on temperature readings
  4. Decrease shock can pressure (Nitrogen reservoirs if you have them)
  5. Adjust compression/rebound settings of front or rear shocks (this only works when suspension is moving such as entering or exiting corner. Steady state cornering (i.e. long sweeper corners require geometry or spring rate adjustments)
  6. Lower front of car (useful for fine tuning after spring and ARBs are about right). This lowers the C.G. and also the roll center.
  7. Increase camber (until braking performance starts to drop)
  8. Increase caster (until steering system begins protesting)
  9. Increase toe-out (too much will cause straight line instability and reduced straight-away speeds, also increased tire wear)
  10. If all of these have been exhausted the driver is likely overdriving the vehicle and needs to slow the car down more and late apex the important corners that lead onto long straightaway. Work with what you have!

Rear Changes:

  1. Raise rear watts pivot
  2. Use stiffer rear springs
  3. Increase shock can pressure (Nitrogen reservoirs if you have them)
  4. Stiffen rear Anti-Roll Bar
  5. Raise the rear ride height (useful for fine tuning after spring and ARBs are about right)
  6. Change tire pressure
  7. Adjust compression/rebound settings of front or rear shocks (this only works when suspension is moving such as entering or exiting corner. Steady state cornering (i.e. long sweeper corners require geometry or spring rate adjustments)

If push is at high speeds only, take wing angle out.

 

Symptom: Rear Oversteer (car is loose)

Rear Changes: Begin here first

  1. Lower rear watts pivot
  2. Soften rear ARB (smaller diameter or remove completely)
  3. Softer rear springs
  4. Decrease shock can pressure (Nitrogen reservoirs if you have them)
  5. Lower rear ride height (useful for fine tuning after spring and ARBs are about right)
  6. Change tire pressure (Also useful for fine tuning)
  7. Adjust compression/rebound settings of front or rear shocks (this only works when suspension is moving such as entering or exiting corner. Steady state cornering (i.e. long sweeper corners require geometry or spring rate adjustments)
  8. If oversteer is at high speeds only, increase wing angle.

Front Changes

  1. Stiffer front ARB (switch to holes closer to chassis pivot)
  2. Install stiffer front springs
  3. Change tire pressure based on temperature readings
  4. Increase shock can pressure (Nitrogen reservoirs if you have them)
  5. Adjust compression/rebound settings of front or rear shocks (this only works when suspension is moving such as entering or exiting corner. Steady state cornering (i.e. long sweeper corners require geometry or spring rate adjustments)
  6. Raise front of car (raises C.G. and roll center)
  7. Decrease camber (to a point)
  8. Decrease Caster
  9. If all of these have been exhausted the driver can try going deeper into corners to gain an advantage over the other vehicle since getting back on the throttle will take longer. Consider placing vehicle in a location that makes overtaking on corner exit difficult.

 

Symptom: Excessive Brake Dive but Cornering Perfect

Changes Front & Rear

  1. Increase anti-dive (done by either lower the forward front lower control (LCA) chassis pivot point or raising the rearward (LCA) pivot point.
  2. Increase rebound force of rear shocks
  3. Increase front spring rate (do this last since it will change the cornering balance of the car and spring changes at all 4 corners may be required)

 

Symptom: Vehicle harsh under braking like the front springs are too stiff. Braking decreases drastically on rough or bumpy surfaces.

Changes Front & Rear

  1. Decrease anti-dive (done by either raising the forward front lower control (LCA) chassis pivot point or lowering the rearward (LCA) pivot point.
  2. Decrease rebound force of rear shocks
  3. Decrease front spring rate (do this last since it will change the cornering balance of the car and spring changes at all 4 corners may be required)

 

Symptom: Cannot put power down during corner exit

This issue can be difficult because the vehicle may have too much or too little anti-squat or spring rate. If the car doesn’t have enough anti-squat or is too soft it will take weight too long to transfer to the rear tires. Conversely, if the car has too much anti-squat or too stiff of springs the suspension will not be able to do its job and the car will break traction over minor irregularities on the track surface. Therefore, some experience is required to correctly diagnose this situation.

Changes Front & Rear

  1. Increase anti-squat (done lower the rear lower control arm pivot point on the axle bracket but can also be done by raising the rear ride height. At ride height the rear lower arm should be slightly uphill (3-5 degree) toward the front of the vehicle.
  2. Soften or stiffen the compression setting on the rear shocks
  3. Increase or decrease rebound settings on front shocks
  4. Apply the throttle more smoothly (driver issue)

 

Other Helpful Generalities:

A stiffer vehicle will generate higher tire temperatures. If tire temp readings show overheating then a softer spring package or lower roll center may be needed. This will also show up as the race progresses. We prefer to have a car that is significantly faster then the field early since it will allow you to go hard at the beginning and open up a large lead which can demoralizing the competition. The field will battle it out amongst themselves while you assume a conservative pace maintaining your lead. This is obviously not a good strategy if competition is really close since the stiffer car will be forced to slow down later in the race because of used up tires.

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