TEIN FLEX Z Coilovers Explained
TEIN, range by range
FLEX Z is the TEIN most people will buy: 131 kits from £888 to £1,332, a full-length adjustable coilover with 16 damping positions, made in Yokohama, and the most affordable adjustable kit in our new suspension ranges.
It also needs the most care when you order. Cameron noticed it on the first page of listings: a large share of FLEX Z kits are written for a particular market version of a car, Japanese, American or Chinese, and the listing says so in bold at the top. Garreth's reaction was that it is exactly why the kit suits the import crowd, as long as nobody assumes a UK registration settles the question.
Here is how FLEX Z is built, what the numbers on each listing mean, the market check, and the fitting notes worth knowing.
- Twin-tube damper, sealed by crimping, made in Yokohama
- Full-length adjustable: height changes without touching stroke or preload
- 16 damping positions on one knob, compression and rebound together
- Typical springs about 7 kgf/mm front and 6 rear
- 40 kits are for Japanese-market cars only
- EDFC compatible on most cars, sold separately
- Replacement service, not overhaul; 12 month UK warranty
How FLEX Z is built
FLEX Z uses a twin-tube damper. TEIN's own explanation is that, against a monotube, twin-tube gives a longer stroke with less force pushing back, which is where the ride comfort comes from. The damper is sealed: TEIN narrows the top of the shell, fills it with oil and gas, and crimps it shut.
That sealed build is how TEIN keeps the price down, because it takes a lot of steps out of production. The trade is servicing. A FLEX Z cannot be overhauled; TEIN replaces the damper unit instead, and sells it on its own without the mounts, brackets or springs.
The rest of the kit is where TEIN spends the money. Springs are cold formed from SAE9254 steel and powder coated. The green on the mounts and brackets is a two layer, one bake powder coat TEIN holds a Japanese patent for, and the shells carry a separate coating against chips and rust. TEIN says it has had no claims for parts seized by rust across two million shock absorbers, which matters on a British car that sees a salted road.
Height and damping
FLEX Z is full-length adjustable. The ride height is set by winding the lower bracket up or down the damper body, so the stroke stays the same and so does the spring preload. On a coilover that adjusts height with the spring seat, lowering the car eats into the travel. On FLEX Z it does not, and TEIN says the ride changes very little between heights.
Damping has 16 positions on one knob, moving compression and rebound together, and Cameron’s advice is to start soft on the road and firm it a few clicks for a trackday, and to write down where it was.
| Upper mounts on our FLEX Z listings | Kits |
|---|---|
| Reinforced rubber front mounts | 80 |
| Camber-adjustable front mounts | 31 |
| Original front mounts kept | 14 |
TEIN picks the mount for each car. Camber adjustment comes on the pillow ball mounts; the rubber ones keep the noise and vibration down on a road car.
What the numbers on a listing mean
Here is the S2000 kit, VSH64-C1SA3, as an example; every FLEX Z listing carries the same set of figures for each car it fits.
| Figure | S2000 AP1 on VSH64-C1SA3 | What it means |
|---|---|---|
| Recommended front height change | -35 to -15mm | The range TEIN recommends, from standard height |
| Recommended rear height change | -45 to -25mm | Negative means lower |
| Maximum front range | -117 to +4mm | How far the kit physically goes, not a target |
| TEIN reference setting | -25 mm front; -35 mm rear | A sensible first setting |
| Spring rates | 10 front, 10 rear, kgf/mm | Multiply by about 9.8 for N/mm |
From the live listing.
Across all 418 applications the typical front spring is 7 kgf/mm and the typical rear 6. The typical recommended front drop runs from -50mm to -30mm. TEIN’s own advice is to lower in 5mm steps, keep the balance close to standard, and not to chase the bottom of the range, because lower means less stroke left to work with.
The market check
Of our 131 FLEX Z kits, 40 are for Japanese-market cars only, and the listing says so in bold before anything else. 35 more list one or more market versions, Japanese, US, Chinese or German, against each application. The remaining 56 state no market at all.
The reason it matters is that the same model name can hide a different car. Springs, dampers and mounting points can vary between markets, and TEIN builds a kit to one of them. The GR Yaris shows it neatly: VSTN0-C1AA3 is listed for cars up to March 2024, and VSBLV-C1AA3 for Japanese-market cars from April 2024.
Which cars it covers
| Make | Kits | Make | Kits |
|---|---|---|---|
| Toyota | 31 | Mercedes-Benz | 3 |
| Honda | 28 | Acura | 3 |
| Nissan | 15 | Daihatsu | 2 |
| Subaru | 14 | BYD | 2 |
| Mazda | 11 | Scion | 2 |
| Lexus | 8 | Volkswagen | 2 |
| Mitsubishi | 6 | Ford | 1 |
| Suzuki | 5 | Tesla | 1 |
| BMW | 4 | Fiat | 1 |
| Infiniti | 4 | Abarth | 1 |
| Audi | 3 |
Kits naming each make. The full range is on the TEIN FLEX Z category page.
Toyota and Honda lead, from the MR2 and Supra to the GR86 and GR Yaris, and the list also reaches the big Japanese people carriers that are popular as imports, the Alphard, Vellfire and Estima, and a handful of European and American cars, most of them listed against a specific market version.
Fitting notes worth knowing
- EDFC recommended. On 16 kits TEIN recommends its EDFC controller, because reaching the adjuster means removing the rear seats or the damper
- Side lift-up seats. Several Alphard and Vellfire kits are not suitable for cars with the factory side lift-up seat
- Dust boots and insulators. Some rears need the original dust boot or spring insulator modifying
- Camber at the bracket. A few kits, the GR Yaris among them, allow camber adjustment at the lower bracket with supplied collars
EDFC
TEIN's Electronic Damping Force Controller puts a motor on each damper and a controller on the dash. It works with FLEX Z on most cars and is sold separately.
Alignment
Any change in height changes the geometry. Have the alignment done once the car has settled at its new height.
Servicing
TEIN suggests a check every two to three years on the road. FLEX Z dampers are replaced, not rebuilt. The UK warranty is 12 months.
Common questions
Is FLEX Z comfortable enough for daily driving?
That is what TEIN designed it for: a twin-tube damper chosen for a longer stroke and a softer push back. Stay inside the recommended height and start at the soft end of the 16 positions.
Can FLEX Z be rebuilt?
No, it is sealed, so TEIN replaces the damper unit instead, without needing new mounts, brackets or springs.
Does lowering the car make it ride worse?
Less than on many coilovers, because full-length adjustment keeps the stroke and preload the same, though going very low still costs travel.
My car is a UK car. Can I use a Japanese-market kit?
Only if TEIN lists your exact version, so send us the chassis code and build date and we will check.
Where is FLEX Z made?
TEIN states it is made at its plant in Yokohama, Japan.
Who it suits
A road car that wants to sit right and drive better, and an import owner who wants a kit written for their exact car. Garreth would put FLEX Z on either without a second thought.
Cameron draws the line at regular circuit use. The kit copes with trackdays, but a car that lives on track is better served by MONO SPORT, with its firmer springs and a damper that can be rebuilt. Our TEIN guide puts the two side by side for the cars that have both.
Manufacturer reference: TEIN UK FLEX Z. Shop the TEIN FLEX Z range.
The rest of the TEIN series: TEIN at GSM Performance.
Send us the registration and, if it is an import, the chassis code and build date. We will match the market and the date range before you order.
Send the registration or VIN, and if the car is an import, its chassis code and build date. We will match it to the right FLEX Z part number and go through the fitting notes with you before anything is ordered.
