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ST Suspensions ST XA Coilover Kit - BMW 3 Series E90 - 18220048
ST Suspensions coilover kits are the entry-level line of the KW Automotive group, built on the same engineering at a lower price. The kit replaces the standard dampers and springs with one height-adjustable assembly, which lets the body come down under control and firms up the car through a corner without giving up everyday comfort.
ST coilover kits adjust height at all four corners, for anyone who wants a lower stance and firmer handling without moving to competition suspension. The higher series (ST XA, ST XTA, ST XTA plus 3) add damping adjustment, which is useful for moving between everyday driving and the occasional mountain road or track day. Everything mounts to the car's original points, with no irreversible changes to the body.
| Main make | BMW |
| Main model | 3 (E90) |
| Series | ST XA |
| Year | 2005+ |
| Max front axle load | up to 1090 kg |
| Max rear axle load | up to 1135 kg |
| Front drop | 15-45 mm |
| Rear drop | 15-40 mm |
Vehicle compatibility
| Model | Version | Years |
|---|---|---|
| BMW 3 (E90) | sedan, coupé; 4WD | 11/2005 - 01/2012 |
Frequently asked questions
What is the difference between ST X and ST XA?
ST X has one fixed damping setting; ST XA lets you set the rebound damping, which is how you tune the ride.
What separates ST XTA from ST XTA plus 3?
ST XTA adds damping adjustment set separately front and rear; ST XTA plus 3 adds more steps, for finer tuning.
Can the height be adjusted after fitting?
Yes. An ST coilover is reset by turning the thread, with no new parts needed.
Does the ST kit come with a TUV certificate?
Some kits carry a technical certificate for the specific car. Check the product page for your model: some applications need individual vehicle approval under local law.
Will the car lose comfort after fitting?
A drop within the recommended range is fine for normal use. Bumps come through more firmly than on standard suspension, most of all on ST X, which has no damping adjustment.
Does the geometry need setting after fitting?
Yes. Lowering changes camber and caster, so have the geometry checked and set at a specialist workshop.
Does the ST kit include new springs?
Yes. An ST coilover is a complete damper and spring assembly, built to work together. Replacing the springs on their own is not recommended.
Does it work with air or self-levelling suspension?
No. ST kits generally do not work with factory air suspension. Check the technical notes for your car.
How far can the car be lowered?
The range varies by model and series. Each product page lists the approved range for front and rear, in millimetres.
Can they be fitted front only, or rear only?
ST coilover kits are made as a full set, front and rear, so the car stays balanced.
What warranty do ST products carry?
Check the warranty terms shown on the product: they vary by application.
Does fitting differ from the standard dampers?
Everything mounts to the car's original suspension points, with no irreversible changes to the body, but have the work done at a specialist workshop.
Can I run larger wheels afterwards?
Lowering changes the clearance to the wheels and tyres. Check the sizes before you change wheels.
Will they last in daily use?
They are built for daily road use. How long they last depends on the roads and on maintenance, so have them checked periodically.
Can the damper be replaced on its own?
No. The ST coilover kit is supplied and fitted as one damper and spring assembly.
What if the car already has lowering springs on it?
Tell us when you order: some applications have restrictions for cars whose suspension has already been changed.