Bilstein B4 Shock Absorbers 21-030505 – BMW 3 Series, Z1

Bilstein B4 OEM Replacement Front (universal) shock absorber — Bilstein Shock Absorber 21-030505

Specifications

• Fitting Position: Front (universal)
• Type: Gas Pressure
• Damping System: Twin-Tube
• Mounting: Bottom plate
• Series: B4 OEM Replacement

Performance

B4 is Bilstein's OE-replacement damper: valving matched to the car's original specification so ride height, body control and comfort return to how the vehicle left the factory. Nothing is uprated and nothing is lowered — it is the right choice when worn dampers have made the car float, bounce or wander, and you want factory behaviour back rather than a firmer setup. This unit is twin-tube, the construction Bilstein specifies where the original fitment used it.

Fitment

Fits 4 BMW models including 3er Cabriolet (E30) and 3 Series (E30) — see the full list below. Verify fitment using the vehicle compatibility checker above. OEM References: 1 135 635, 1 131 071, 1 133 560, 31 30 1 133 438, 1 135 892.

What's Included

One Bilstein B4 damper unit for the front axle (either side) — a single shock absorber, not a pair and not an axle set. Order two to do an axle, four for the whole car. Mounting is bottom plate. Bump stops, dust covers, top mounts and fixings are not included.

Warranty

Backed by Bilstein's manufacturer warranty against defects in materials and workmanship. Cover assumes correct installation, the correct tightening torques, and serviceable bump stops and dust covers. A damper run without its protection parts will be scored by road grit — that is wear, not a defect. As an official reseller in the EU, Suspengo also handles your statutory conformity rights on this purchase — contact us first and we deal with the manufacturer.