MetalCloak True Dual Rate Front Coils, 5.5in, Jeep Wrangler JK 4-Door, Pair

A dual rate coil solves a problem an ordinary coil cannot. To give plenty of articulation a spring has to be soft — but then the vehicle squats under load and wallows on the road. To hold ride height and handling it has to be firm — but then a wheel lifts off the ground before the suspension has used its travel.

True Dual Rate has two working zones in one spring: the lower, stiffer section carries the vehicle and governs on-road behaviour; the looser upper section comes into play as a wheel droops, letting it follow the ground. On top of that, one of the longest free lengths in the industry — long enough that the coil stays in its bucket even at full droop.

High tensile chrome silicon steel, black powder coat. The kit contains 2 front coils and 2 upper isolators. Easy to fit, 1–2 hours, no body modification.

⚠ Check which version you need — 2-door and 4-door take different coils

A 2-door JK is lighter at the back and shorter, so MetalCloak specifies its coils separately. These are for the 4-door (JKU) only, and for a 5.5in lift only. The full front range runs like this:

Note: the same coil gives a different lift depending on the body — so what matters when ordering is the number of doors, not just the height you want. Not sure? Get in touch and we will work it out.

How the "virtual bucket" works

The manufacturer explains it simply: the dual rate design effectively lowers the coil bucket. The lower coils act as the load-carrying spring, while the looser upper coils behave like an extension of the bucket. The result: the coil stays seated even at full suspension droop, with no tendency to buckle.

Without that design, a spring of the required length would have to be soft enough that — as the manufacturer puts it — simply loading the Jeep up with supplies would affect ride height and quality.

Coil data

FROM THE DRAWING AND SPEC Free length: 22in (approx. 559 mm) Solid height: 8in (approx. 203 mm) Wire diameter: Ø 9/16in (approx. 14.3 mm) Inside diameter, top: Ø 4½in Inside diameter, bottom: Ø 4 1/32in Designation: SS-2140

Note: the manufacturer's specification table gives a free length of 22in, while the dimensioned drawing shows approx. 23.50in. We quote the table figure as the primary one.

? Do not powder coat — it voids the manufacturer's warranty

This is the most important warning on the page and it applies to every True Dual Rate coil. The manufacturer states plainly that the baking process in powder coating can change the metallurgical properties of the coil and cost it its lift properties — in other words, the vehicle simply settles. Powder coating voids the warranty, stated or implied.

The coils arrive in a factory black powder coat and are meant to stay that way. If colour matters to you, talk to us before buying about other options.

What these coils work best with

The manufacturer puts it in its notes: True Dual Rate coils are engineered to perform best with Duroflex control arms and 6Pak or RockSport shocks. It is not a formal requirement but a matter of matching — a spring with this much free length needs a shock with the travel to use it.

• Shocks: 6Pak BLACK for a 5.5in lift (front part no. 7432F) or RockSport Long(er) — all stocked here.
• Duroflex arms: at 5.5in, long arms are worth considering — we stock them individually and as complete systems.
• Sway bar links: at 5.5in the factory ones are too short. Front: 7221 (with the SWAY BAR button) or 7220 (without). Rear: kit 7241 with spacers.

The manufacturer also states that its components passed FMVSS 126 certification configured with 37in tires, full body armour and a suspension lift.

What's in the kit

• 2 × front True Dual Rate coil
• 2 × upper front coil isolator

The isolators are thermoset elastomer, made specifically for these coils — the manufacturer states they outlast the factory parts. The rear kit (part no. 7209) contains no isolators — that is the difference between front and rear.
The manufacturer offers an optional Front True Dual Rate Coil Sleeve Kit — it is not part of this kit; we order it in.
The matching rear coils (part no. 7209) are stocked here — coils are changed as a front-and-rear set.

Technical data

• Application: Jeep Wrangler JK 2007–2018, 4-door, front axle
• Lift: 5.5in
• Contents: 2 coils + 2 upper isolators
• Material: high tensile chrome silicon steel
• Design: dual rate (True Dual Rate), designation SS-2140
• Free length: 22in (approx. 559 mm)
• Solid height: 8in (approx. 203 mm)
• Wire diameter: Ø 9/16in (approx. 14.3 mm)
• Inside diameters: top Ø 4½in, bottom Ø 4 1/32in
• Isolators: thermoset elastomer, specific to these coils
• Finish: black powder coat — do not re-coat
• Installation difficulty: easy
• Body modification: none
• Time to install: 1–2 hours
• Shipping weight: approx. 13.61 kg (taken from the matching rear kit 7209 — the manufacturer gives no weight for the optioned version)
• Country of manufacture: USA

Who they are for

For 4-door JKs built around a 5.5in lift — that is, for large tyres and real off-road use. This is the tallest lift in the JK True Dual Rate range, so usually part of a build rather than a standalone purchase.

If you are after a moderate lift and better comfort, the 2.5in or 3.5in coils from the same family are the right ones — get in touch and we will give you the part numbers.

Installation notes

Fitting itself is simple: the manufacturer rates it easy and allows 1–2 hours with no body modification. In practice coils are changed together with the shocks, and it is the moment to check sway bar link lengths and control arm angles.

An alignment is mandatory after a ride-height change — the manufacturer recommends a specialist alignment after any MetalCloak suspension installation. Szekla4x4.pl is an authorised MetalCloak dealer with a workshop specialising in off-road suspension: we will fit them, set the alignment and check clearances at full travel. Send us your configuration and we will put the set together.

Why they are worth it

• Two rate zones in one spring — comfort and ride height without giving up articulation.
• One of the longest coils on the market: it stays in the bucket at full droop.
• Chrome silicon steel — resistant to sagging.
• Dedicated upper isolators included.

Frequently asked questions

Do they fit a 2-door JK?

No. These are 4-door only. On a 2-door, a 5.5in lift comes from a different coil — part no. 7183.

Are rear coils included?

No. This is the front pair. The rear for the same setup is part no. 7209 — we stock it. Coils are changed as a set: lifting only one axle changes driveshaft angles and geometry.

Can I have them powder coated in a colour?

No. The manufacturer warns that the baking process can change the coil's metallurgical properties and cost it its lift properties. Powder coating voids the warranty.

Are the isolators included?

Yes, two upper front isolators. The rear kit does not include them.

Do I need MetalCloak shocks?

It is not a requirement, but the manufacturer states the coils are matched to 6Pak or RockSport shocks and Duroflex arms. At a 5.5in lift, a shock with too little travel wastes the length of these coils.

Is an alignment needed afterwards?

Yes. The manufacturer recommends a specialist alignment after any suspension installation.

Is any cutting or drilling required?

No. Fitting requires no body modification.