Here is a decision chart that will help you fine tune suspension setups. We avoid spring rates because this is usually dependent on the valving on your suspension. We assume you aren’t super lowered and riding on bump stops. You must maintain correct ride height designed for your suspension system to maintain optimal ride geometry.
Step 1 – Fine Tune Suspension with Rebound Tuning:
- First you will have to open all valves open to softest setting and then begin your testing.
| Symptom | Front Rebound | Rear Rebound |
|---|---|---|
| Understeer at turn-in | Soften | - |
| Oversteer at turn-in | - | Soften |
| Understeer at exit | Stiffen | - |
| Oversteer at exit | Stiffen | - |
Step 2 – Tire Pressure Tuning:
- 30-33 PSI for track days. Monitor the PSI as they start to rise from the heat. Adjust accordingly
- 36-38 PSI for normal driving to conserve tire wear.
| Symptom | Front Tire Pressure | Rear Tire Pressure |
|---|---|---|
| Inner Wear Only | Decrease | Decrease |
| Overcooked Tires | Increase | Increase |
Step 3 – Camber Tuning:
| Symptom | Front Camber | Rear Camber |
|---|---|---|
| Understeer at turn-in | Increase | - |
| Oversteer at turn-in | Decrease | Increase |
| Understeer at exit | Increase | - |
| Oversteer at exit | Decrease | Increase |
| Rotate car | Increase | Small Increase |
Step 4 – Swaybar Tuning:
| Symptom | Front Sway | Rear Sway |
|---|---|---|
| Understeer at turn-in | Soften | - |
| Oversteer at turn-in | Stiffen | Soften |
| Understeer at exit | Soften | Stiffen |
| Oversteer at exit | - | Remove |
Step 5 – Compression Tuning:
| Symptom | Front Compression | Rear Compression |
|---|---|---|
| Skipping over bumps | - | Decrease |
| Power skidding on exit | - | Increase |
| Porpoise during braking | Increase | - |
Step 6 – Bushing Tuning:
- Spherical/Solid Bushings will articulate better under bind than Poly.
- Sway links must be installed pre-loaded, meaning weight of the car on the front suspension. Both sway links should bolt into the sway bar without any force. Otherwise, you will encounter a steering wheel that is easier to turn in one direction than the other since one side will be preloaded incorrectly. If you lower your car you will need adjustable sway links to achieve this optimal pre-load neutrality.
- We recommend spherical Rear Trailing Arm Bushing due to articulation issues with Poly bushings.
- We recommend spherical or delrin Front Control Arm Bushings.
- We recommend matching differential, engine, transmission bushings.
- We recommend solid subframe bushings.
- We recommend spherical RSM due to articulation issues with Poly bushings.
- We recommend spherical lower control arms due to articulation issues with Poly bushings.
Check out our Alignment Specs Guide for your E46 M3 for additional information on suspension setups for track, daily and auto cross. Do you have any suggestions or feedback? Comment below!