Best Coil Assist Kit for 4WD Touring (2026 Picks)
Coil assist kits solve a specific problem: sagging rear coil springs on 4WDs that carry camper gear, canopy tool storage or tow heavy trailers. This guide ranks the vehicle-specific coil assist kits Boss Air Suspension currently supplies and tells you which one actually suits touring use in 2026.
- Boss Air Suspension's coil assist kit for Toyota LandCruiser 300 and Prado 250 (up to 2 inch lift) is the strongest pick for full-time touring rigs. Buy.
- The Nissan Navara NP300 coil assist kit (up to 2 inch lift) suits dual-cab owners splitting work and weekend touring loads. Buy.
- RAM 2500 owners running big camper trailers get a dedicated coil assist kit (2014 onwards, up to 2 inch lift). Buy for heavy tow setups.
- Coil assist only fits factory coil-sprung rear ends - leaf-spring utes need a load assist airbag kit instead.
- Confirm your rear suspension type and current lift height before ordering any coil assist kit in 2026.
Why this matters
A coil-sprung 4WD that sits low at the back under load isn't just uncomfortable. It changes headlight aim, reduces ground clearance and makes the vehicle harder to control when towing.
A coil assist kit for the Toyota LandCruiser 300 and Prado 250 works with the factory coil spring rather than replacing it. An airbag sits inside the spring and adjustable air pressure adds support only when you need it - loaded for a trip, not sitting empty in the driveway.
That's the core appeal for touring 4WDs in 2026: one setup that handles both an unladen commute and a fully loaded trip to the Kimberley without permanently stiffening the ride.
How we ranked these kits
The list below covers coil assist kits currently listed with vehicle-specific fitment on the Boss Air Suspension range, not every airbag product in the catalogue. Ranking criteria: whether the kit works with the factory coil spring (not a leaf-spring load assist kit), lift height compatibility, and how well the vehicle suits genuine touring use - long-distance travel, camper trailers, canopy storage.
This is based on current fitment listings and product documentation published in 2026, not independent load testing. Always confirm exact fitment against your vehicle's build date and existing suspension before ordering.
The ranked list
1. Toyota LandCruiser 300 / Prado 250 Series coil assist kit - the tourer's pick
One memorable detail: this kit is built specifically for vehicles running up to a 2 inch lift, which covers most touring-spec 300 Series and Prado 250 builds on the road in 2026.
The LandCruiser and Prado are the default choice for long-distance Australian touring, and both carry real weight - dual batteries, drawer systems, rooftop tents, fridges. The coil assist airbag sits inside the factory coil spring and lets you dial up support only when the vehicle is loaded for a trip.
Installation keeps the factory ride quality intact when the vehicle is empty, which matters for owners who also use the vehicle for the school run. Verdict: Buy for LandCruiser 300 and Prado 250 owners running camper trailers, caravans or heavy canopy setups.
2. Nissan Navara NP300 coil assist kit - the dual-purpose ute pick
One memorable detail: fitment covers NP300 4WD variants up to a 2 inch lift, matching the most common suspension upgrade path for this ute.
The NP300 gets used two ways in Australia - as a tradie's daily driver during the week and a tow vehicle for a camper or boat on weekends. That dual role is exactly where rear-end sag shows up fastest, because the load changes from empty tray to full canopy and trailer ball weight within the same day.
The coil assist kit gives Navara owners a way to add support for the tow or load-carrying trip without running an overly firm ride the rest of the week. Verdict: Buy for NP300 owners who regularly switch between empty and loaded running.
3. RAM 2500 coil assist kit - the heavy tow rig pick
One memorable detail: this kit suits RAM 2500 models from 2014 onwards, with fitment rated to up to a 2 inch lift.
RAM 2500 owners in Australia are typically towing large caravans or fifth-wheelers, and the factory coil rear end can still sag under serious ball weight even on a vehicle built for towing. A coil assist kit gives these owners adjustable support to keep the rear end level when hitched up, rather than running a permanently stiff spring rate.
This is a bigger investment than a ute-specific kit and suits a narrower group of owners - those running heavy fifth-wheel or large dual-axle van setups. Verdict: Buy if you're regularly towing near the vehicle's rated limits; Consider if your towing is occasional and lighter.
“If your coil-sprung 4WD already sits level when it's empty, coil assist is solving a problem you don't have yet.”
What about the Nissan Patrol?
The Nissan Patrol runs a coil-sprung rear end too, and it's a common question from tourers. Boss Air Suspension covers what a coil assist setup fixes and how it works on the Patrol in more detail - check current fitment availability before assuming a vehicle-specific kit exists for your build.
Comparison table
| Vehicle | Lift compatibility | Best for | Verdict |
|---|---|---|---|
| Toyota LandCruiser 300 / Prado 250 | Up to 2 inch | Full-time touring, camper trailers | Buy |
| Nissan Navara NP300 4WD | Up to 2 inch | Dual-purpose work and tow | Buy |
| RAM 2500 (2014 onwards) | Up to 2 inch | Heavy caravan and 5th-wheel towing | Buy / Consider |
What to avoid
- Fitting a coil assist kit to a leaf-spring rear end. It won't fit - leaf-sprung utes and wagons need a load assist airbag kit instead, not a coil assist kit.
- Ordering the wrong lift-height variant. A kit rated for up to 2 inch lift won't sit correctly on a vehicle running a taller lift, and vice versa.
- Assuming coil assist increases your vehicle's legal payload, GVM or towing capacity. It doesn't, unless the fitment is part of an approved GVM upgrade with documentation to match.
Where to buy
- Confirm your rear suspension type first - coil-sprung or leaf-sprung - before searching for a kit, since the two use completely different products.
- Match the kit to your current lift height, not your target lift height, unless you're fitting the lift and the kit together.
- Check current pricing and stock directly on the Boss Air Suspension site before ordering, since availability on vehicle-specific kits changes through 2026.
FAQ
What is the best coil assist kit for 4WD touring in 2026?
For full-time touring, the Toyota LandCruiser 300 and Prado 250 coil assist kit is the strongest pick because both vehicles carry heavy camper and canopy loads on long trips. Dual-purpose ute owners are better matched to the Nissan Navara NP300 kit.
Is a coil assist kit better than a load assist airbag kit?
Neither is better outright - they suit different rear suspension types. Coil assist works with a coil-sprung rear end, while load assist airbag kits are built for leaf-spring utes and wagons.
Does a coil assist kit increase towing capacity or GVM?
No. A coil assist kit improves rear suspension support and ride height under load, but it does not change your vehicle's legal payload, GVM or towing capacity unless it's part of an approved GVM upgrade.
Can I fit a coil assist kit to a leaf-spring ute?
No. Coil assist kits are built for factory coil-sprung rear ends only. Leaf-spring utes need a load assist airbag kit instead.
Does a coil assist kit suit a lifted 4WD?
Yes, provided the kit matches your lift height. The kits covered in this guide are rated for vehicles running up to a 2 inch lift - fitment outside that range needs to be confirmed before ordering.
How much support does a coil assist kit add?
Support is adjustable through air pressure, so it can be increased for a loaded trip and reduced for unladen driving. Exact pressure ranges vary by kit and should be checked against the product's fitment documentation.
Is there a coil assist kit for the Nissan Patrol?
Coil assist setups for the Nissan Patrol are covered in Boss Air Suspension's technical guide on what the fitment fixes and how it works. Check current availability before assuming a vehicle-specific kit is listed.
What warranty comes with a Boss Air Suspension coil assist kit?
Boss Air Suspension coil assist kits are backed by a five-year warranty, in line with the rest of the load assist range.
One last thing
Coil assist only works on vehicles that already run a coil-sprung rear end from the factory - it can't be retrofitted onto a leaf-spring ute no matter how well it's installed. That's why the Boss Air Suspension range keeps coil assist kits and leaf-spring load assist kits as two separate product lines rather than one universal fix, and why checking your rear suspension type is the first step, not an afterthought, before you buy in 2026.
