opensus
Formula SAE car: suspension hardpoints and geometry
Pushrod double A-arms, 10 inch wheels and wings. The numbers are representative of this kind of car, not measured from a real one: use them as a starting point and to learn the tool.
Vehicle
| Total mass | 300 kg |
| Wheelbase | 1550 mm |
| Front weight | 46 % |
| CG height | 290 mm |
| Front brake bias | 62 % |
Results
| Result at the design position | Unit | Front | Rear |
|---|---|---|---|
| Suspension type | Double A-arm | Double A-arm | |
| Static camber | deg | -1.50 | -1.00 |
| Static toe-in | deg | -0.10 | 0.15 |
| Caster | deg | 3.07 | 0.00 |
| Kingpin inclination | deg | 5.57 | 6.63 |
| Scrub radius | mm | 27.6 | 23.9 |
| Mechanical trail | mm | 9.7 | 0.0 |
| Roll center height | mm | 27.5 | 44.8 |
| Track | mm | 1220 | 1196 |
| Anti-dive (front) / anti-lift (rear) in braking | % | 12.6 | 13.5 |
| Anti-lift (front) / anti-squat (rear) under drive | % | 0.0 | -0.2 |
| Motion ratio, spring to wheel | 0.674 | 0.655 | |
| Spring rate | N/mm | 60 | 65 |
| Wheel rate | N/mm | 27.2 | 27.9 |
| Ride frequency | Hz | 3.11 | 2.88 |
Roll gradient for the whole car: 0.81 deg/g.
Front hardpoints (left corner)
Coordinates follow the opensus conventions: X forward from the front axle line, Y left from the centreline, Z up from the ground, at the loaded static position.
| Point | Name in links | X mm | Y mm | Z mm |
|---|---|---|---|---|
| Upper arm, front inner | ucaFront |
110.0 | 280.0 | 292.0 |
| Upper arm, rear inner | ucaRear |
-110.0 | 280.0 | 288.0 |
| Upper ball joint | ucaOuter |
-8.0 | 550.0 | 330.0 |
| Lower arm, front inner | lcaFront |
120.0 | 200.0 | 113.0 |
| Lower arm, rear inner | lcaRear |
-120.0 | 200.0 | 117.0 |
| Lower ball joint | lcaOuter |
3.0 | 570.0 | 125.0 |
| Tie rod inner | tieInner |
-68.0 | 215.0 | 148.0 |
| Tie rod outer | tieOuter |
-70.0 | 565.0 | 165.0 |
| Wheel centre | wheelCentre |
0.0 | 604.0 | 222.4 |
| Pushrod at lower arm | rodOuter |
0.0 | 530.0 | 135.0 |
| Pushrod at rocker | rodInner |
0.0 | 260.0 | 420.0 |
| Rocker pivot | rockerPivot |
0.0 | 220.0 | 370.0 |
| Rocker axis | rockerAxis |
40.0 | 220.0 | 370.0 |
| Coilover at rocker | springRocker |
0.0 | 170.0 | 410.0 |
| Coilover at chassis | springChassis |
0.0 | 60.0 | 300.0 |
| Sway bar pivot | arbPivot |
70.0 | 175.0 | 300.0 |
| Sway bar axis | arbAxis |
70.0 | 115.0 | 300.0 |
| Sway bar arm tip | arbTip |
-30.0 | 175.0 | 300.0 |
| Drop link at rocker | arbDrop |
-30.0 | 175.0 | 395.0 |
Rear hardpoints (left corner)
X is measured from the rear axle line.
| Point | Name in links | X mm | Y mm | Z mm |
|---|---|---|---|---|
| Upper arm, front inner | ucaFront |
110.0 | 270.0 | 294.0 |
| Upper arm, rear inner | ucaRear |
-110.0 | 270.0 | 302.0 |
| Upper ball joint | ucaOuter |
0.0 | 535.0 | 335.0 |
| Lower arm, front inner | lcaFront |
130.0 | 190.0 | 124.0 |
| Lower arm, rear inner | lcaRear |
-130.0 | 190.0 | 116.0 |
| Lower ball joint | lcaOuter |
0.0 | 560.0 | 120.0 |
| Toe link inner | tieInner |
-120.0 | 205.0 | 155.0 |
| Toe link outer | tieOuter |
-120.0 | 555.0 | 165.0 |
| Wheel centre | wheelCentre |
0.0 | 594.0 | 221.4 |
| Pushrod at lower arm | rodOuter |
0.0 | 520.0 | 130.0 |
| Pushrod at rocker | rodInner |
0.0 | 250.0 | 415.0 |
| Rocker pivot | rockerPivot |
0.0 | 210.0 | 365.0 |
| Rocker axis | rockerAxis |
40.0 | 210.0 | 365.0 |
| Coilover at rocker | springRocker |
0.0 | 160.0 | 405.0 |
| Coilover at chassis | springChassis |
0.0 | 55.0 | 295.0 |
| Sway bar pivot | arbPivot |
-70.0 | 165.0 | 295.0 |
| Sway bar axis | arbAxis |
-70.0 | 105.0 | 295.0 |
| Sway bar arm tip | arbTip |
30.0 | 165.0 | 295.0 |
| Drop link at rocker | arbDrop |
30.0 | 165.0 | 390.0 |
These tables are generated from the example built into opensus, so they always match what the tool loads.