Adjustable Shocks Settings & Purple Shocks Explained

Adjustable Shocks: What the Settings Actually Control

Adjustable shock absorbers let you tune damping force — the resistance the shock applies as it compresses and extends — to match your vehicle, load, and driving conditions. Most adjustable shocks offer between 3 and 20 clicks of adjustment, with softer settings providing a more compliant, comfortable ride and firmer settings delivering tighter body control and improved handling response. Getting the settings right makes a tangible difference; getting them wrong can make a vehicle feel worse than factory shocks.

The core concept is straightforward: a shock absorber controls how quickly your suspension moves, not how far. Springs determine ride height and load capacity; shocks determine the speed and character of the movement. When a wheel hits a bump, the spring absorbs the energy and the shock controls how that energy dissipates over time. A shock set too soft lets the body continue to bounce after a bump; one set too firm transmits road harshness directly into the cabin and can actually reduce tire contact with the road surface on rough terrain.

Types of Adjustability: Compression, Rebound, and Combined

Not all adjustable shocks offer the same type of control. Understanding which axis of damping a given shock adjusts is essential before making any setting changes.

Compression Damping

Compression damping controls how the shock resists the suspension moving upward into the wheel well — what happens when the wheel hits a bump or the vehicle body rolls into a corner. Increasing compression damping reduces body roll and nose dive under braking, but set too high it causes the suspension to feel harsh over sharp bumps and can cause the tire to skip rather than track the road surface.

Rebound Damping

Rebound damping controls how quickly the shock extends after being compressed — how fast the suspension returns to its normal position after a bump. This is the adjustment that most single-adjustment shocks use. Too little rebound damping and the suspension bounces excessively after bumps (a condition called pogo or float); too much and the suspension packs down over successive bumps, reducing ground clearance and causing the vehicle to sit lower than intended during repeated impacts.

Combined or Piggyback Reservoir Systems

Higher-end adjustable shocks — particularly those used in off-road and performance applications — often feature separate adjusters for compression and rebound, sometimes with a remote or piggyback reservoir that provides additional oil and gas volume. This extra capacity helps maintain consistent damping performance as the shock heats up during extended hard use. Fade resistance — the ability to maintain consistent performance over many cycles — is one area where reservoir shocks meaningfully outperform standard monotube or twin-tube designs under demanding conditions.

Purple Shocks: What They Are and Who Makes Them

In the suspension aftermarket, "purple shocks" most commonly refers to shocks produced by Rancho and King Shocks, both of which use purple as a brand color on certain product lines, as well as shocks from Fox Racing Shox in limited colorways. However, the most widely recognized purple shock absorbers in the truck and SUV market are Rancho RS9000XL shocks, which feature a distinctive purple anodized body and are among the most recognized adjustable shocks in the North American off-road and light truck segment.

The Rancho RS9000XL is a 9-position manually adjustable monotube shock with a 46mm piston — larger than the 35–40mm pistons found in many OEM-replacement shocks, which provides more fluid volume and improved heat dissipation during extended use. The nine adjustment settings range from a soft, comfort-oriented setting (position 1) through to a firm, performance-oriented setting (position 9), allowing the driver to adapt the shock to different payloads, road conditions, and driving styles without tools in most installations.

Rancho RS9000XL Adjustment Settings Guide

Rancho publishes general guidance for their 9-position adjustment range. The following settings are starting points — final tuning depends on vehicle weight, tire size, lift height, and load:

• Positions 1–3: Soft setting. Recommended for daily highway driving with no load, prioritizing ride comfort on smooth roads. Also suitable for light off-road trails at low speed where tire compliance over small obstacles is more important than body control.
• Positions 4–6: Mid-range setting. The default starting point recommended by Rancho for most street and mixed-use driving. Balances ride quality with adequate body control for normal cornering and braking. Position 5 is frequently cited as the best all-around starting point for unloaded trucks used primarily on pavement.
• Positions 7–9: Firm setting. Recommended when towing or carrying significant payload, for aggressive off-road driving, or for spirited on-road driving where body control is prioritized. Position 9 is the firmest available and will feel harsh on rough pavement if used without a load to compress the suspension.

Other Purple Shock Options in the Market

Beyond Rancho, several other manufacturers produce purple or violet-colored shock absorbers:

• King Shocks: A premium off-road shock manufacturer based in California, King uses purple anodizing on some of their remote reservoir and coilover products. King shocks are used in desert racing, rock crawling, and high-end truck builds. Their OEM performance replacement shocks for Ford, RAM, and GM trucks are sold with purple anodized bodies and are a significant step up from Rancho in both price and adjustability.
• Bilstein B8 5100 Series: While primarily yellow, Bilstein offers some regional market variants in different finishes. However, true purple Bilstein shocks are less common — this is primarily a Rancho and King color association.
• Generic and budget aftermarket shocks: Purple-anodized shocks appear from various manufacturers specifically because the color is associated with quality adjustable shocks in the truck market. When purchasing purple shocks from unfamiliar brands, verify the adjustment mechanism type (click detent vs. continuous), piston diameter, and whether the product carries any performance certification or warranty.

How to Set Adjustable Shocks for Different Driving Conditions

There is no single correct setting for adjustable shocks — the right setting depends on the combination of vehicle weight, load, road surface, and intended use at any given time. The following guidance covers the most common scenarios for truck, SUV, and performance vehicle owners.

Daily Street Driving (Unloaded)

For a lifted truck or SUV used primarily on paved roads without payload, a mid-range setting (4–6 on a 9-position shock, or 8–12 on a 20-click shock) is the correct starting point. The suspension needs enough damping to prevent float and body roll without being so firm that it transmits every road imperfection into the cabin. If the ride feels excessively harsh over expansion joints or small potholes, reduce by 1–2 positions. If the body feels like it continues to move after bumps or leans excessively in corners, increase by 1–2 positions.

Towing and Heavy Payload

Adding significant weight — either in the bed or via a trailer tongue weight — compresses the rear suspension and changes how the shock behaves. With more weight, the spring is already partially compressed, and the shock operates in a different part of its range. When towing or carrying load near or above 50% of payload capacity, increase shock firmness by 2–3 positions relative to your unloaded street setting. This restores body control, reduces squat, and improves stability under braking with a loaded trailer.

Off-Road and Trail Driving

Off-road settings depend heavily on the terrain type. On slow technical trails (rock crawling, steep descents), a softer setting allows maximum wheel articulation — the ability of each wheel to independently follow the terrain while the body remains stable. For rock crawling, settings in the lower third of the adjustment range are typically optimal, as maximizing suspension travel and tire contact matters more than body control at low speeds.

On high-speed desert or gravel driving, the opposite applies — firmer settings prevent the suspension from bottoming out over large whoops and maintain steering precision at speed. Many experienced off-road drivers use a firm setting (upper third) for high-speed off-road runs and return to a softer setting for slow technical sections.

Performance and Track Use

For cars and trucks used on track days or autocross, maximum firmness is generally the starting point — but this is often the area where generic "firmest is best" advice fails. Excessive rebound damping on a track surface with many small bumps causes the suspension to pack down, reducing tire contact patch and actually slowing lap times despite feeling more controlled. The correct approach is to start at full firm and soften the rebound by 2–3 clicks at a time until the car stops skipping over mid-corner bumps while maintaining body control in smooth-surface corners.

Comparing Adjustable Shock Options: Where Purple Shocks Fit

Adjustable shocks span a wide price and performance range. Understanding where Rancho RS9000XL and King Shocks sit relative to other adjustable options helps set realistic expectations for performance and cost.

The Rancho RS9000XL occupies a strong value position in this market: it is the most affordable shock with true multi-position damping adjustment, making it a practical choice for owners who want flexibility without the cost of a reservoir or bypass shock. Its limitation compared to King and Fox reservoir units is thermal management — in extended heavy off-road use, the smaller oil volume heats up more quickly, and damping consistency can degrade during long runs. For daily driving and occasional trail use, this limitation is largely irrelevant.

Common Mistakes When Setting Adjustable Shocks

Even with quality adjustable shocks installed, incorrect setup undermines their benefit. These are the errors that appear most consistently in practice.

• Setting all four corners identically without considering weight distribution. Most trucks and SUVs are significantly heavier at the front (due to the engine) than the rear. Front and rear shocks typically require different settings to achieve balanced handling — running the same setting front and rear often results in an over-damped front and under-damped rear, or vice versa.
• Always running at maximum firmness. Many users assume maximum stiffness equals maximum performance. In reality, overly firm rebound damping on bumpy surfaces causes the suspension to pack down — each successive bump finds the suspension already partially compressed, reducing both comfort and tire contact. The correct setting is the firmest that still allows the suspension to fully extend between bumps.
• Not adjusting for load changes. The primary advantage of adjustable shocks is the ability to adapt to different conditions. Owners who set their shocks once at installation and never change them are not benefiting from the adjustability they paid for.
• Mismatching shocks to spring rates. Shocks and springs are a system. Installing stiff adjustable shocks on soft, worn springs produces unpredictable handling. If the springs need replacement, do it before making final shock adjustments — the spring rate significantly affects how a given shock setting feels in practice.
• Adjusting only one end of the vehicle. Changing damping at one axle without considering its effect on the other creates imbalance. Stiffening the rear significantly without a corresponding front adjustment shifts handling toward oversteer; stiffening only the front pushes toward understeer.