In our previous blog about shock adjustment, we explored the basics of setting up single-adjustable coilovers—the most common type found on performance cars today. Now, it’s time to level up and dive into the world of two-way adjustable coilovers. These allow you to fine-tune both rebound and compression damping independently, giving you greater control over your car’s handling for street driving and track performance.
If you haven’t read part one yet, we recommend starting there. We covered crucial concepts like damping speeds (high, mid, low) and how to manage suspension travel, which will all apply to two-way adjustable shocks as well. But for now, let's focus on how to set up these advanced shocks without overcomplicating things.
What Exactly is a Two-Way Adjustable Shock?
A two-way adjustable shock gives you two independent knobs—one to adjust rebound damping and one to adjust compression damping. Unlike single-adjustable shocks (which typically only let you tweak rebound), this setup offers much more flexibility for dialing in your car’s handling characteristics.
Rebound Damping: Controls how fast the shock extends after being compressed. It affects how the car settles after cornering, braking, or hitting bumps.
Compression Damping: Controls how fast the shock compresses when you hit bumps or load up the suspension during acceleration, braking, or cornering.
This extra adjustability means you can fine-tune your car’s behavior to suit different driving scenarios—from daily street driving to specialized track events like autocross, drifting, and drag racing.
Starting with the Basics: Keep a Log!
Before you start turning knobs, the first rule of shock adjustment is don’t get lost in the process. It’s easy to forget where you started, especially when you're adjusting multiple settings on multiple shocks. To avoid confusion, grab a notepad and write down every change you make. This step is crucial when you’re dealing with two adjustments per shock (four total for the car).
Step 1: Set Your Shocks to Full Soft
If your coilovers don’t come with a manufacturer-recommended baseline setting, you should start with both rebound and compression at their softest settings.
Why Start Soft?
By starting at the softest setting, you can gradually dial in the right amount of damping. Going too stiff right away can cause your car to skip, hop, and lose grip—something you definitely want to avoid.
Step 2: Adjust Compression First
Most high-quality shocks have compression damping that primarily affects low-speed shock shaft velocities—the zone responsible for controlling body roll, squat, and dive. This is where you’ll feel the most significant changes when adjusting compression.
How to Adjust:
- Start with full soft.
- Increase compression damping two clicks at a time until you start feeling the car become harsh or lose grip.
- When you reach the point where the car feels too stiff or bouncy, back off one click.
This method ensures you have the maximum amount of compression control without making the car too stiff to maintain mechanical grip.
Step 3: Adjust Rebound
Once your compression is set, move on to adjusting rebound. Rebound controls how fast the shock extends after being compressed. Too much rebound can cause your suspension to "pack down" over a series of bumps, while too little can make the car feel floaty and unstable.
How to Adjust:
- With compression set, start with rebound at full soft.
- Gradually increase rebound damping one click at a time until the car feels controlled but not harsh.
- If the car starts to feel bouncy or stiff, you've added too much rebound. Back off one click.
Tips for Optimizing Your Setup
When setting up two-way adjustable coilovers, it’s all about balance. You want your car to have enough damping to control body movement without losing grip or becoming uncomfortable to drive. Here are a few general tips:
- More compression damping gives sharper turn-in and reduces body roll, but too much can make the car bouncy and stiff.
- More rebound damping helps control how quickly the car settles after bumps or weight transfer, but too much can cause the suspension to pack down over multiple bumps.
- Don’t equate stiffness with better handling. More damping isn’t always better. Start soft, and only add damping as needed to control body movement.
Advanced Adjustments for Track Days
Once you’ve dialed in a good baseline setup for daily driving, you can start fine-tuning for the track. Here’s how:
- For sharper turn-in: Increase front compression damping. This helps the car react more quickly to steering inputs.
- For better corner exit: Add rear rebound damping. This slows the rear extension and helps plant the rear tires for more grip.
- To reduce squat: Increase rear compression damping. This prevents the rear of the car from squatting too much under acceleration, keeping the car more balanced.
Signs of Over-Adjusting
Too Much Compression:
- Severe tire shock: The car feels bouncy and lacks grip.
- Harsh ride: The car feels stiff and uncomfortable, especially over bumps.
- Understeer: Too much front compression can make the car feel like it’s sliding or washing out in corners.
Too Much Rebound:
- Suspension packing down: The car feels like it's getting lower and lower as you hit consecutive bumps.
- Skipping tires: The tires lose contact with the road, especially over rough surfaces.
The Bottom Line
Two-way adjustable shocks offer a world of possibilities for fine-tuning your car’s suspension. But with great power comes great responsibility! Stick to the process we outlined here—start soft, adjust compression first, then rebound—and you’ll be well on your way to mastering your coilovers like a pro.
Don’t be afraid to experiment on the track and learn how each adjustment affects your car’s handling. With enough practice, you’ll be able to dial in your setup for any driving condition, whether it’s autocross, drifting, or your favorite canyon road.
