Coilovers Explained How To Choose: What You Need to Know

What Are Coilovers and How They Work

Coilovers are suspension components that combine a shock absorber (damper) and coil spring in a single, height-adjustable unit. The name literally means "coil over shock" - the spring sits on a threaded collar that slides up and down the shock body, allowing you to adjust ride height without changing spring preload.

The shock absorber controls how fast your suspension compresses and rebounds, while the spring supports the vehicle's weight and handles the initial impact from road irregularities. By combining these into one adjustable unit, coilovers give you control over both ride height and suspension geometry that separate springs and shocks simply can't match.

Modern coilovers use a piston inside a sealed chamber filled with hydraulic fluid and pressurized gas. As the piston moves, it forces fluid through valves, creating resistance that controls suspension movement. The spring rate and damping characteristics work together to determine how your car handles bumps, corners, and weight transfer.

Coilovers vs Springs and Shocks

The main advantage of coilovers over separate lowering springs and stock shocks is adjustability and matched tuning. When you install lowering springs on stock shocks, you're often mismatching components that weren't designed to work together. Stock shocks are valved for stock spring rates, so they can feel soggy or create harsh impacts when paired with stiffer aftermarket springs.

Coilovers solve this by engineering the damper and spring as a matched system. The shock valving is designed specifically for the spring rates provided, creating balanced performance. You also get height adjustability without preloading the spring, which maintains proper suspension geometry throughout the adjustment range.

However, coilovers do cost more than springs alone. A decent set of lowering springs might run $200-400, while entry-level coilovers start around $800-1200. The question becomes whether the added adjustability and matched tuning justify the extra cost for your specific build goals.

Types of Coilovers: Twin-tube vs Monotube

Understanding the difference between twin-tube and monotube construction helps explain why some coilovers cost $1000 while others cost $3000 for the same car.

Twin-tube coilovers use an inner working cylinder surrounded by an outer reservoir tube. The piston moves in the inner tube, and fluid flows between the chambers through valves. This design is less expensive to manufacture and works well for street driving, but it generates more heat under hard use because the fluid has less volume to dissipate temperature.

Monotube coilovers house the piston, fluid, and gas charge in a single larger-diameter tube. This design handles heat better because there's more fluid volume, and the gas charge can be higher pressure. Monotubes typically respond faster to suspension inputs and maintain consistent damping characteristics even when hot. That's why most serious track-focused coilovers use monotube construction.

For daily driving and occasional spirited runs, twin-tube coilovers from brands like BC Racing or D2 Racing work perfectly fine. If you're planning regular track days or autocross, monotube designs from KW, Ohlins, or AST are worth the extra investment.

Key Specifications That Matter

When comparing coilovers, focus on these specifications that actually affect how your car drives:

Spring Rate: Measured in kg/mm or lbs/in, this determines how much force is needed to compress the spring one unit of distance. Higher spring rates create less body roll in corners but transmit more road harshness. Most street cars work well with rates 20-50% higher than stock, while track cars might use rates 100-200% higher.

Damping Adjustment: Entry-level coilovers might have non-adjustable damping or basic rebound adjustment. Mid-tier units often offer 32-way adjustable rebound damping. High-end coilovers provide separate compression and rebound adjustment, sometimes with high-speed and low-speed circuits for each.

Height Adjustment Range: Most coilovers offer 2-4 inches of height adjustment. More isn't always better - excessive lowering can create geometry problems and reduce suspension travel. Check what ride height range maintains proper suspension geometry for your chassis.

Top Mount Type: Pillow ball mounts offer more precise geometry but transmit noise and vibration. Rubber mounts maintain comfort but allow some deflection under load. Some coilovers offer both options or camber-adjustable top mounts.

How to Choose the Right Coilovers for Your Build

Your coilover choice should match your driving style and build goals, not just your budget. Here's how to narrow down the options:

Daily Driver with Occasional Fun: Look for twin-tube coilovers with rubber top mounts and moderate spring rates. BC Racing BR series, Tein Flex Z, or Fortune Auto 500 series work well here. You want 16-32 way damping adjustment to fine-tune comfort vs performance.

Weekend Warrior/Track Days: Step up to monotube construction with higher spring rates and more adjustment options. KW V3, Ohlins Road & Track, or AST 5100 series provide the consistency needed for performance driving while remaining street-friendly.

Dedicated Track Car: Focus on coilovers with separate compression and rebound adjustment, remote reservoirs if needed, and spring rates matched to your aerodynamic package. Penske, JRZ, or custom-valved Ohlins are common choices.

Show Car: Prioritize maximum height adjustment and appearance. Air suspension might be worth considering for extreme drops while maintaining drivability.

Don't get caught up in brand loyalty - every manufacturer makes different tiers for different applications. A $1000 KW isn't necessarily better than a $1000 BC Racing; they're just targeting different markets.

Installation and Setup Considerations

Coilover installation looks straightforward, but proper setup requires attention to detail. Most coilovers come preset to a middle height setting, but you'll need to adjust for your specific ride height goals and align the suspension afterward.

When setting ride height, adjust both height collars and spring perch together to maintain proper thread engagement. Never run more than 3-4 threads showing on the height adjustment - this can create stress concentrations that lead to failure. If you need more drop, consider shorter springs or a different coilover with more adjustment range.

After installation, get an alignment immediately. Lowering your car changes suspension geometry, often adding negative camber and altering toe settings. Without proper alignment, you'll experience uneven tire wear and compromised handling.

Initial damping settings should start conservative - set adjusters to middle positions and adjust from there based on how the car feels. Stiffer isn't always better; over-damped suspension can actually hurt handling by preventing the tires from following road surfaces properly.

Maintenance and Care

Quality coilovers can last 60,000-100,000+ miles with proper care, but they do require more maintenance than stock suspension. The height adjustment threads are particularly vulnerable to corrosion, especially in winter climates where road salt is used.

Clean and lubricate the threads every 6 months using appropriate anti-seize compound. Avoid getting lubricant on the shock shaft, as this can damage seals. If you live in a harsh climate, consider coilovers with anodized or stainless steel construction.

Watch for oil leakage around shock seals - small seepage is normal, but visible dripping indicates worn seals that need replacement. Most quality coilovers can be rebuilt rather than replaced when seals fail, making them more economical long-term than cheaper alternatives.

If you track your car regularly, consider having coilovers serviced annually. Track use generates more heat and cycles, accelerating wear on internal components. Many manufacturers offer rebuild services that restore original performance at a fraction of replacement cost.

Frequently Asked Questions

What spring rates should I choose for my coilovers?

For street driving, choose spring rates 20-50% higher than stock specifications. Track-focused builds can run 100-200% higher rates but will sacrifice ride comfort. Most coilover manufacturers provide recommended rates for different applications - start there and adjust based on your specific needs.

Do I need camber plates with my coilovers?

Camber plates allow adjustment of wheel camber angle and are useful if you've lowered significantly or want to fine-tune alignment. They're not strictly necessary for mild drops but become important for track use or aggressive lowering where you need to correct suspension geometry.

Can I install coilovers myself?

Basic mechanical skills and proper tools make coilover installation manageable for most enthusiasts. You'll need spring compressors for strut-style applications and should plan for professional alignment afterward. If you're not comfortable with suspension work, professional installation ensures proper setup and safety.

How low can I go with coilovers?

Maximum drop depends on your specific coilover and chassis combination, but 2-3 inches is typically safe for most applications. Going lower often requires additional modifications like rolled fenders, shortened bump stops, or revised suspension geometry to maintain proper operation.

Are coilovers worth it over lowering springs?

Coilovers provide matched damper/spring tuning, height adjustability, and often better long-term value through rebuildability. If you want significant lowering, track use capability, or the ability to fine-tune your setup, coilovers justify their higher initial cost compared to springs and stock shocks.

Parts & Products

Trimotive Performance carries coilovers from all major manufacturers to match your performance goals and budget. Our coilover selection includes street-friendly options like BC Racing BR series for daily drivers, as well as track-focused monotube units from KW and Ohlins for serious performance builds. We also stock camber plates and adjustable endlinks to complete your suspension setup. Every coilover purchase includes free shipping across Canada and the US, plus technical support to help you choose the right spring rates and damping settings for your specific application.