ST X Coilovers Vauxhall Signum 03-08

ST X Coilovers for Vauxhall Signum (2003-2008) – 30-60 mm Lower, Height Adjustable, Fixed Damping

This ST X kit replaces the standard springs and dampers on the Vauxhall Signum (2003-2008) with a height-adjustable coilover set. It lowers the car by approx. 30-60 mm front and rear, which sharpens the steering, cuts body roll and closes up the wheel arch gap. The ride height is set on threaded struts, so you can go for a subtle drop or use the full approved range, and change it again later.

The ST X is the entry point to the ST range. It is built around a damper setting that ST have matched to this specific car, so there is nothing to adjust beyond ride height. Shaped (progressive) springs keep the ride compliant over small bumps and firm up as the suspension compresses, which makes it a good fit for a daily driver that needs to look lower and feel tighter without becoming harsh. ST is part of the KW automotive group, and the kit is developed and made in Germany using KW engineering.

This kit is for the Vauxhall Signum with the 1.8, 1.9 CDTI, 1.9 CDTI 16V, 2.0 DTI, 2.0 Turbo, 2.0 i Turbo, 2.2 DTI, 2.2 DTI 16V and more, up to a 1230 kg front axle load. Check the Fitment section below before ordering.

Specifications

• Front lowering: approx. 30-60 mm
• Rear lowering: approx. 30-60 mm
• Max front axle load: up to 1230 kg
• Max rear axle load: up to 1140 kg
• Height adjustment: Stepless, on threaded strut housings
• Minimum ride height (wheel hub centre to arch edge): front 330 mm, rear 335 mm
• Damping: Fixed, pre-set by ST for this vehicle
• Springs: Shaped progressive springs
• Strut housings: Galvanised steel
• Approval: Parts certificate (German §19.3)

Lowering figures are ST's, measured against the standard car. The actual drop varies with engine, equipment and tolerances on each car, and the springs settle slightly after the first few hundred miles.

Key Features

• Stepless ride height adjustment on a coarse, dirt-resistant trapezoidal thread
• Damper setting developed by ST for this vehicle, so no setup is needed beyond ride height
• Shaped progressive springs for a comfortable ride with firmer support in corners
• Galvanised, multi-sealed steel strut housings for long-term corrosion protection
• Composite spring perches with stainless steel inserts that stay easy to adjust for years
• Dust covers and bump stops protect the damper seals and act as an extra spring under heavy load
• Developed and built in Germany, based on KW engineering
• Supplied with a parts certificate and fitting instructions

What's in the Kit?

• 2 x height-adjustable front coilover struts with springs
• 2 x rear dampers
• 2 x rear springs with height-adjustable spring seats
• Composite spring perches with stainless steel inserts
• Dust covers and bump stops
• Parts certificate and fitting instructions

Please note: the photos are for reference only and show a typical ST X kit. The exact struts, brackets and springs supplied depend on your car.

Fitment

• Vauxhall Signum Z03 (Mar 2003 to Oct 2008)
• Vauxhall Signum CC Hatchback Z03, Z-C/S (May 2003 to Dec 2008)
• Engines: 1.8, 1.9 CDTI, 1.9 CDTI 16V, 2.0 DTI, 2.0 Turbo, 2.0 i Turbo, 2.2 DTI, 2.2 DTI 16V, 2.2 direct, 2.2 i, 2.8 V6 Turbo, 3.0 CDTI, 3.0 V6 CDTI, 3.2 V6

Not suitable for: any vehicle not listed above. Contact us with your registration if you are unsure.

Adaptive dampers: if your car has electronically controlled dampers, the system must be switched off with a cancellation kit (sold separately) to stop warning lights and fault codes: electronic damping: KW cancellation kit (part no. 68510253).

Installation

Fitting means removing the original struts, springs and dampers and fitting the ST units in their place. We recommend a qualified workshop experienced with coilovers. A spring compressor is needed to strip down the original front struts. The original top mounts, bearings and fixings are reused, so check them for wear and replace any that are worn. Set the ride height within the approved range, tighten the suspension bolts with the car's weight on its wheels, and torque everything to the manufacturer's figures. A four-wheel alignment is required once the car is at its final ride height. Re-check the height and alignment after the first few hundred miles, once the springs have settled.

Download ST's documents for this kit: Fitting instructions (PDF), Parts certificate (PDF).

Before you start:

• Disconnect any ride height sensors (headlight levelling or self-levelling) before removing the old struts.
• Clean the threads before adjusting, and start with the height adjusters in the middle of their range.

After fitting:

• Do not go below ST's minimum height, measured from the wheel hub centre to the wheel arch edge: front 330 mm, rear 335 mm.
• Expect the car to settle a further 5-10 mm once it has been driven, then re-check the height.
• Check there is at least 5 mm clearance between the tyres and the suspension through the full steering and suspension travel.
• Have the headlight aim reset, along with any other height-dependent systems.
• ESP/ABS warning lights can appear after fitting. Some clear after a short drive, others need full steering lock both ways or a reset with a diagnostic tool.
• On cars with radar or camera driver assistance systems, have the calibration checked after lowering.

Will this fit my Vauxhall Signum?

It fits the Vauxhall Signum (2003-2008) with the 1.8, 1.9 CDTI, 1.9 CDTI 16V, 2.0 DTI, 2.0 Turbo, 2.0 i Turbo and more. Check the Fitment section for the body styles and exclusions, or send us your registration and we will check.

How low will my Vauxhall Signum sit?

ST quotes a drop of approx. 30-60 mm front and rear compared with standard. The exact drop varies from car to car with engine, equipment and tolerances. ST also sets a minimum: the distance from the wheel hub centre to the wheel arch edge must stay above approx. 330 mm at the front and 335 mm at the rear.

Can I adjust the damping?

No, the damping is pre-set by ST to suit the springs, so there is nothing to set up. You only adjust the ride height. If you want adjustable damping, look at the ST XA.

Will the ST X make my Vauxhall Signum ride harshly?

The ST X uses progressive springs and a fixed damper setting chosen by ST for this car, so it is firmer than standard but still suits everyday driving. Lowering a long way or fitting low-profile tyres will firm up the ride more than the coilovers themselves.

Do I need an alignment after fitting?

Yes. Changing the ride height changes camber and toe, so a full four-wheel alignment is needed once the car is at its final height, and again after any later change.

My car has adaptive dampers. Will this kit fit?

Only with the correct KW cancellation kit, which switches off the electronic damper control so no warning lights appear. The kit number is in the Fitment section. Some versions are not suitable for adaptive dampers at all, so contact us if you are unsure.

Is it road legal in the UK?

Yes. It is designed for road use and comes with a German parts certificate. Keep the ride height within ST's approved range and tell your insurer about the modification.

What is the difference between ST and KW coilovers?

ST is part of the KW group and its coilovers are made in Germany using KW engineering. ST uses galvanised steel strut housings and offers fewer adjustment options than KW's stainless steel Variant range, which keeps the price lower.

Is it covered by a warranty?

Yes, ST covers it against defects in materials and workmanship. If a part ever needs replacing, contact us with your vehicle details and order number.