Anti-Dive Explained: How Suspension Geometry Resists Brake Dive
Brake hard and the nose of the car drops. That is load transferring to the front axle and compressing the front springs. Anti-dive is suspension geometry that sends part of that load through the control arms instead of the springs, so the nose drops less. It does not reduce the load transfer itself — that depends only on deceleration, center of gravity height and wheelbase — it changes the path the load takes into the body.
How arm angles carry load
Look at the front suspension from the side. If the control arm pivots are arranged so the arms' side-view lines converge toward a point behind the front wheel, that point is the side-view instant center. Under braking, the tire's braking force pushes rearward at the contact patch. If the line from the contact patch to the instant center slopes upward toward the rear, part of that braking force pushes up on the body through the arms. That upward push is anti-dive.
The angle is that of the line from the front contact patch to the side-view instant center, measured from the ground. Front brake share is the fraction of total braking force made by the front axle, typically around 0.6 to 0.75.
| Example input | Value |
|---|---|
| Wheelbase | 2,600mm |
| Center of gravity height | 500mm |
| Front brake share | 0.70 |
| Line angle | 3° |
| Anti-dive | about 19% |
Those inputs are an illustration, not figures for any particular car. At 100%, the arms carry all of the transferred load and the front does not dive at all under braking. Road cars usually sit well below that.
Why not 100%?
- Harshness over bumps under braking — with a lot of anti-dive, the wheel has to move forward as well as up to absorb a bump while the brakes are on. The suspension feels stiff and can lose grip on rough surfaces, exactly when it is needed.
- Caster change — the arm geometry that gives anti-dive usually changes caster as the suspension moves, which changes steering feel during braking.
- Driver feedback — some dive tells the driver how hard the car is braking.
How it changes on a modified car
Anti-dive is set by pivot locations, so it moves whenever those do:
- Lowering — changes the arm angles in side view and lowers the center of gravity. The percentage usually shifts; in which direction depends on the layout.
- Caster adjustments on a strut car — moving the lower ball joint forward with a tension rod tilts the geometry in side view and can change anti-dive.
- Inboard pivot changes — anti-dive kits and offset bushes raise or lower one of the lower arm's inner pivots, which is the most direct adjustment.
- Brake bias — moving bias rearward reduces the front brake share and with it the front anti-dive effect.
The rear axle has the matching property under braking, called anti-lift, and under power the rear geometry gives anti-squat.