STREET ADVANCE Z4 has threading type ride height adjustment system.;The ride height can be adjusted by moving the lower spring seat up or down. Its simple structure allows for easier handling.;Standard ride height for STREET ADVANCE Z4 is set at 1 inch (approx. 25mm) higher than the original, to accommodate various driving scenes from streets to off-roading.;STREET ADVANCE Z4 is designed and configured to be most suitable for the lifted height. Simply raising the standard height can lead to insufficient rebound stroke impairing the stability and also make the camber angle positive on strut suspensions.;STREET ADVANCE Z4 is tested on each vehicle models to optimize the dimensions and settings, in order to secure sufficient strokes and to enable the best suited alignment.;Sealed Structure;A New Formula and a New Structure!;Making an Incredibly Low Price a Reality;About the Sealed Structure;The top end of the shell pipe is narrowed, oil and gas are injected, and the whole unit is sealed by crimping the metal.;This new approach massively shortens the production process. As a result, we have succeeded in vastly cutting production cost.;Twin-Tube System;Compared to the regular mono-tube system, twin-tube attains longer stroke with a smaller repulsive force, resulting in high ride comfort.;Roads may have all sorts of surface conditions. This calls for shock absorbers with ample stroke, that operate smoothly.;Thanks to this unique characteristic, you can negotiate gaps and bumps steadily on rough roads, meaning a smooth ride at low speed and stability at high speed.;Hydraulic Bump Stop (H.B.S.);More comfort and higher durability at maximum passenger and cargo load.;How the H.B.S. Mechanism Works;When regular shock absorbers fully stroke, their bump rubbers are compressed. The energy that is generated by that escapes as a repulsive force, which can disturb the vehicle’s behavior. Furthermore, repeated full strokes can damage the damper.;In the same situation, FLEX AVS, featuring H.B.S., internally converts the impact of the stroke to thermal energy (heat) and absorbs it, strongly reducing the impact that disturbs the vehicle’s behavior. With less damage to the dampers, H.B.S. also contributes to their durability.;The Hydraulic Bump Stopper (H.B.S.) Mechanism;In shock absorbers with inactive or no H.B.S., the operative valve (green) floats, and oil flows freely through the base valve ports. Resistance to the flow from the shim stack then, causes damping force.;Near full compression, when the piston rod strokes beyond a predetermined point, the operative valve is pushed down and activates H.B.S.: the base valve ports are narrowed, blocking the oil flow. This results in high damping force.;A relief valve serves to suppress sudden damping force increase, when the pressure in the cylinder exceeds its regular level. br;The setup of the H.B.S. mechanism is optimized per vehicle model, with the right activation point and damping force.;Uses OE Mounts;STREET ADVANCE Z4 uses the vehicle’s original upper mounts (not included in our product kit).;High Durability and Reliability;Optimal Dust Boot;Thanks to its smooth compression and high durability, the dust boot guards the piston rod from damage, and keeps foreign material out of the shock absorber. (Some vehicles use their OE dust boots);No-Sag Spring;Cold formed with SAE9254 steel (minimum tensile strength 200 kgf/mm2), our springs are outstandingly sag-proof and boast extreme resiliency.;Superior rust protection is ensured with a highly durable powder coating that does not peel or flake. Our high-quality springs can be used without worries, in any conditions.;High-Performance Damper Oil;Since TEIN’s damper oil maintains a stable viscosity in a broad temperature range, it sustains smooth stroke and reliable damping force in a variety of circumstances.;Due to excellent anti-foaming properties, it’s resistant to cavitation (bubble forming). Since it withstands high heat too, it’s suitable for intense sport driving as well.;Furthermore, the damper oil keeps up its superior performance long-term, because it’s resistant to deterioration over time.;Rust-Proofing;TEIN-Green Powder Coating;A bright TEIN-green powder paint is used on the shock absorber’s shell case. Our powder coating technique produces an extremely strong and durable barrier. No harmful organic solvents are used, for minimal pollution.;Superior durability and corrosion resistance are achieved by TEIN’s patented 2-Layer, 1-Bake powder coating method, which uses 2 layers of anti-rust paint on a blasted surface. (Japanese patent number 4347712);Special Surface Treatment ‘ZT Coating’;Our unique ZT Coating surface treatment on the ride height adjustment thread is abrasion resistant against gravel/debris, and further enhances its corrosion resistance.;With zero claims for stuck parts due to rust in 500,000 shock absorbers, TEIN shock absorbers are amazingly rustproof. We’re confident of customer satisfaction even in coastal areas or regions with heavy snowfall.;Damping Force Adjustment;STREET ADVANCE Z4 features 16-level damping force adjustment, for simultaneous adjustment of compression and rebound.;Modify ride comfort and handling according to your preference, changing the properties of the shock absorber with the adjustment dial.;Compatible with EDFC Series (Optional);The EDFC Series offer easy damping force adjustment from the driver’s seat.*;Some vehicle models are not compatible;A motor instead of adjustment dial;EDFC Active Pro;EDFC Active;EDFC II