Tein Street Flex A Coilovers - 2015+ Subaru WRX STI

The TEIN FLEX A products are made with a Hydraulic Bump Stopper (H.B.S) this provides more comfort and hight durability at the maximum passenger or cargo load. 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 the FLEX A, featuring H.B.S., internally convert the impact of the stroke to thermal energy (heat) and absorb 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. 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. The setup of the H.B.S. mechanism is optimized per vehicle model, with the right activation point and damping force.

Front Specifications:

• Damping Force Adjustment: Y
• Full-Length Ride-Height Adjustable: Y
• Upper Mount: CAMBER ADJ
• Recommended Ride Height (mm): -30
• Recommended Ride Height (inch): -1.2
• Ride Height Adjustable Range:
  • Max Low (mm): -74
  • Max Low (inch): -2.9
  • Max High (mm): -1
  • Max High (inch): 0
  • Recommended Low (mm): -40
  • Recommended Low (inch): -1.6
  • Recommended High (mm): -20
  • Recommended High (inch): -0.8
• Spring
  • Rate (kgf/mm): 8
  • Rate (lbs/in): 448
  • SP PART#SQ080-01175
  • Free Length (mm): 175
  • I.D. (mm): ID65

• Damping Force Adjustment: Y
• Full-Length Ride-Height Adjustable: Y
• Upper Mount: R/U
• Recommended Ride Height (mm): -25
• Recommended Ride Height (inch): -1
• Ride Height Adjustable Range:
  • Max Low (mm): -85
  • Max Low (inch): -3.3
  • Max High (mm): 16
  • Max High (inch): 0.6
  • Recommended Low (mm): -35
  • Recommended Low (inch): -1.4
  • Recommended High (mm): -21
  • Recommended High (inch): -0.6
• Spring:
• Rate (kgf/mm): 7
• Rate (lbs/in): 392
• SP PART#SW070-01175
• Free Length (mm): 175
• I.D. (mm): ID70

• Year: 2015-2021
• Make: Subaru
• Model: WRX STI
• Drivetrain: 4WD
• Chassis: VAF
• Motor Size: 2500
• Vehicle Region: USA

• Rr: Interior Needs To Be Cut Or Removed, To Avoid Interference.

• Twin-Tube System
  • Considering the use of larger tires/wheels and the lowered ride height, FLEX A uses a twin-tube system, in pursuit of ride comfort on streets.
  • In order to maintain the ride quality on streets with rough spots here and there, a shock absorber has to have sufficient stroke, be low-frictional and move smoothly.
  • As an oil chamber and a gas chamber are not arranged serially in a twin-tube system, it is easy to secure enough stroke. Also, low gas pressure keeps friction low.
  • Its smooth stroke movement makes it possible to follow rough and bumpy road surfaces quite well, offering supple ride at low speed and stable ride at high speed.
• Full-Length System for Ride Height Adjustment w/Minimal Change in Ride
  • Full-length ride height adjustment system, used for FLEX A, enables adjustment of ride height by adjusting the case length, without changing the damper stroke length and/or spring pre-load. This has the advantage that the change in ride quality is kept minimal when the height is adjusted.
  • This system not only makes it possible to maintain a good balance between the low-down appearance and ride comfort but also provides more setting choices for sport driving as well.
• Damping Force Adjustable
  • FLEX A has ever-popular 16-level damping force adjustment (comp./rebound together) feature with the use of needle valve.
  • By turning the adjustment knob, damping force (stiffness) is adjusted linearly step by step, to change the ride and handling of the car to suit the driver's needs/preferences.
  • Use of well-reputed "ADVANCE Needle" at the needle valve for oil flow control widens damping force adjustable range to about 200% of the existing lineups.
  • Whether it's for the handling characteristics of sport driving or for the ride quality according to numbers of passengers, finding the most desirable setting is easier than ever.
• Compatible with EDFC Series
  • With EDFC (Electronic Damping Force Controller) series installed, damping force can be controlled from the cockpit with ease.
  • Stepping motors attached in place of adjustment knobs control the damping force quickly and accurately. Use of EDFC turns 16-level adjustment into finer 32-level or 64-level adjustment mode (64-level only available with EDFC ACTIVE / EDFC ACTIVE PRO), to provide the optimum performance by fully utilizing the damping force adjustable range drastically widened by the use of "ADVANCE Needle".
  • With EDFC ACTIVE / EDFC ACTIVE PRO, damping force can be controlled automatically according to changes in G-force and/or vehicle speed, to offer very smooth and slick ride like never before.
  • Some models are NOT compatible with EDFC series.
• Upper Mount Design
  • FLEX A kit includes upper mounts exclusively designed for each vehicle model; either reinforced rubber mounts or pillow ball mounts.
  • Pillow ball upper mounts for front strut suspensions have camber adjustment feature.
  • Some vehicle models use OE mounts.)
• Durable One-Of-A-Kind ZT Coating
  • Upper mounts and lower brackets are coated with rich TEIN green powder paint. This powder paint has high coating film strength, is highly durable yet is low-pollution due to non-use of harmful solvent. After the shot blasting pre-treatment, the patented "2-layer/1-bake" treatment using anti-rust powder paint is applied for superior durability and high corrosion resistance. (Patent No. 4347712)
  • On shell case, TEIN's self-developed one-of-a-kind "ZT Coating" is applied, for tougher protection against chipping, often caused by bounced pebbles, and rust.
• Rigid Bracket & Shell Case
  • For strut suspensions, the sufficiently-thick ribbed plate is used for knuckle bracket to maintain high rigidity.
  • Flange shape edge of the bracket provides larger contact area with the bracket lock, which is fastened with the conical washer inserted in between, to effectively prevent loosening of the bracket lock most commonly occurs on front strut suspensions.
  • Brackets for brake hoses and ABS sensor harnesses etc are exclusively designed for each vehicle model for hassle-free installation. Shell case is made of high-strength steel STKM13C and solidly-constructed for firm handling and stable ride.
• Smooth Ride Height Adjustment & One-of-A-Kind Adjusting Wrench
  • FLEX A has adopted the new wrought aluminum spring seats and low-friction hard-resin thrust washers. These effectively reduces the friction with springs, caused during ride height adjustment, and makes it easier to adjust the ride height with pre-load on the springs.
  • Shell cases are treated with "ZT Coating", a superlow-friction fluorine resin coating, which is tightly baked onto the surface in-house. This special coating provides superior protection against rust and high lubricity, for keeping a smooth adjustment for a long period.
  • FLEX A kit includes one-of-a-kind user-friendly ride height adjusting wrench. It has a 12.7mm (1/2in) sq. hole for attaching spinner handle and/or torque wrench for tightening at high torque.
• No-Sag Springs
  • The included springs are made of high-tensile steel SAE9254 (tensile strength 200kgf/mm2 or over) and cold formed for excellent resistance to sagging and for superior quality stability.
  • The surface is powder coated for superb protection against chipping & peeling, for high durability and for superior anti-corrosion performance.
  • The most suitable shape of spring (straight or barrel-shaped) is determined for each vehicle model, to provide wide ride height adjustable range and to secure sufficient stroke without compromising ride comfort.
• High-Spec Damper Oil
  • Specially-formulated high-spec oil exhibits stable viscosity characteristics at any temperature; from low to high, to allow shock absorbers to stroke smoothly and to generate damping force stably under various conditions. The oil has superior anti-foaming characteristics hence the bubble cavitation and/or thermal degradation hardly occurs, making it even suitable for tough sport driving.
  • The oil also does not deteriorate much with age, making it possible to maintain and deliver superior performance for the long term.