Quick Summary (for beginners)

• Ride height = how high or low the car sits

• Preload = how much the main spring is compressed at full droop

• Preload does NOT change spring rate

• Preload does NOT meaningfully change ride height

• Ride height on Dežru coilovers is set ONLY by the spring perch + helper spring

• Dežru does NOT use adjustable hub brackets, so shock length does not change

Now let’s go deeper.

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Why This Topic Is Confusing

Most generic coilover videos online explain preload using coilovers with adjustable lower mounts.
Those systems allow ride height to be changed without touching the springs, so preload and height feel separate.

But your product line — like high-end motorsport dampers — uses:

✔ fixed-length shock bodies
✔ helper springs
✔ ride height set through the perch alone
✔ preload used only to control droop and initial response

This changes how preload behaves.

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What Is Ride Height?

Ride height is simply how high the car sits when resting on its wheels.

On Dežru coilovers, ride height is controlled exclusively by:

✓ Spring perch position

Threading the perch up → raises the car
Threading the perch down → lowers the car

✓ Helper spring compression

The helper spring fully compresses when the car is on the ground, so it:

• does not affect stiffness

• does not set spring rate

• contributes only to droop and perch positioning

Ride height is NEVER adjusted by changing the shock length on Dežru kits, because the lower mount is fixed.

This preserves bump/droop travel and keeps valving in its designed stroke window.

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What Is Preload?

Preload is how much the main spring is compressed when the suspension is at full droop (wheels hanging).

Example:

• If the spring is 8” free length

• And installed at 7.75” length

• You have 0.25” of preload

This does not change spring rate — the rate is a physical property of the spring itself.

Preload affects:

• initial shock response

• how quickly the car transitions from droop into compression

• how tight the spring stays seated at full droop

• noise reduction

• helper spring collapse behavior

It does not stiffen the suspension in normal driving.

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Preload Does NOT Change Spring Rate

This is one of the most common suspension myths.

Spring rate is measured by force required to compress the spring by 1 inch. Preload doesn’t change the steel, so:

A 450 lb/in spring remains 450 lb/in

• with 0 preload

• with 1/4" preload

• with 1/2" preload

• with 1” preload

Nothing about preload alters the spring’s stiffness.

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Preload Does NOT Meaningfully Change Ride Height (on Dežru coilovers)

On fixed-length assemblies like Dežru:

• Adding preload slightly raises the car only until the helper spring collapses

• Once the helper is compressed, further preload does not lift the vehicle

• Ride height becomes 100% determined by perch position

• Therefore preload is not a height tuning tool

If preload changes your ride height dramatically, the suspension is installed incorrectly.

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How Ride Height Adjusts on Fixed-Length Coilovers

Dežru’s design uses:

• fixed shock body length

• fixed lower mount

• fixed piston stroke

• helper spring + linear spring

Therefore:

Ride height = where you place the spring perch.

Lower perch → car goes down
Raise perch → car goes up

That’s it.

Shock length never changes.
Valving position never changes.
Stroke never changes.

This is a huge advantage for ride consistency and damping performance.

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What Preload Actually Does on a Dežru Coilover

Preload controls droop travel

More preload → less droop
Less preload → more droop

Preload keeps the spring seated

It prevents a loose spring at full extension.

Preload adjusts initial response

A small preload increase makes the suspension feel slightly “tighter” at the very top of the stroke.

Preload does NOT:

• change overall spring stiffness

• meaningfully change ride height

• change damping or valving behavior

• correct sag from overly soft springs

• increase performance on its own

Important:

Too much preload will eliminate droop — this reduces traction and ride quality.

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Understanding Helper Springs in the Mix

Dežru uses helper springs because they:

• Maintain spring contact at full droop

• Prevent spring chatter or noise

• Allow zero-preload installs

• Collapse completely once the car is on the ground

• DO NOT change the main spring rate

The helper spring plays a support role — never a stiffness role.

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Proper Preload Procedure on Dežru Coilovers

✔ Step 1 — Set zero preload

Spin the spring perch up until the main spring just touches the upper mount.

✔ Step 2 — Add 1–2 mm of preload

This ensures the spring is “captured” without applying real compression.

✔ Step 3 — Confirm helper spring is seated

Make sure the helper compresses but stays centered.

✔ Step 4 — Set ride height using the perch

Raise or lower the perch to reach desired height.

✔ Step 5 — Re-check droop

Make sure droop travel remains acceptable for your setup.

✔ Step 6 — Corner balance (optional)

For performance use, corner balancing ensures left/right height accuracy.

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What Happens If You Add Too Much Preload?

• Reduced droop

• Harsh top-out

• Poor small-bump sensitivity

• Worse traction over uneven surfaces

• Higher NVH

• Worse ride quality

Preload is NOT a tuning tool for stance or handling — it is a setup tool.

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Summary: Preload vs Ride Height

Ride Height:

• Set ONLY by perch position

• 0% related to preload

• Not affected by helper springs

• Never done with shock length on a Dežru coilover

Preload:

• Captures the main spring

• Controls droop

• Fine-tunes initial response

• Does NOT change rate

• Does NOT change height

• NOT a performance tuning tool

Dežru’s fixed-length design ensures:

✔ consistent damping
✔ full bump/droop travel
✔ correct valving window
✔ proper spring behavior
✔ no risk of running out of stroke
✔ OEM+ comfort with performance capability

This system is used in real motorsport dampers — and it’s a cornerstone of Dežru engineering.