If there’s one thing that immediately comes to mind when thinking about Ironman 4×4, it’s probably suspension.
While they have a huge range of products for off-roading and overlanding, their wide range of lift kits offers something for every build, at every stage.
So when Ironman announced a brand new suspension that completes their offering, I was very intrigued. Until the IM2.5, we were limited to leveling kits, the Nitro Gas lineup, and the super established Foam Cell Pro line. The IM2.5 has aluminum construction and uses a monotube design. The main benefit of the IM2.5 is a larger piston surface area, which is able to offer more precise linear damping.
I’ve been running this kit for almost a year now, and with thousands (15K+) of daily driving miles and plenty of trail time, I wanted to put together this review.
Table Of Contents
What’s In The Kit
If you’ve been researching lift kits for your 5th Gen, you already know there’s no shortage of options. What sets the Ironman Stage 4 IM2.5 apart from most of the competition is that it doesn’t just lift the truck; it corrects it. This is the full-send version of Ironman’s best kit, and it includes everything you need to do the job right.
Component Breakdown
Front IM2.5 Coilovers: 2.5″ monotube design machined from 6061-T6 aircraft-grade aluminum with a 57mm billet aluminum piston offering 60% more surface area than traditional designs, charged with 200PSI nitrogen gas and Fuchs hydraulic oil, sealed with NOK seals; ride-height adjustability via Acme thread makes dialing in height for different loads genuinely easy, and seals remain clean with no oil film or weeping at 15,000 miles.
Rear Inverted Monotube Shocks: Inverted monotube design with an internal floating piston (IFP) that separates the nitrogen charge from the hydraulic oil for consistent damping performance; smooth and progressive through full travel with no fade observed even after extended high-speed gravel days.
Pro Forge Upper Control Arms (Stage 2): Geometry improvement over stock is real and measurable; even tire wear across the tread at 15,000 miles proves it out; Ironman doesn’t cut corners on construction.
Panhard Bar (Stage 3): Transforms rear composure on road and trail; on a lifted 5th Gen Runner, this is not optional and is an underappreciated piece of the puzzle to correct geometry.
Sway Bar End Links (Stage 3): Strong, properly sized for the lift, and unremarkable in the best possible way
Adjustable Lower Trailing Arms (Stage 4): Completes the kit by correcting pinion angle with no vibration, and remains adjustable if lift height changes down the road; no bushing slop, no creak.
Don’t forget the customer support and a 4-year, unlimited-mile warranty!
Why Get The Stage 4?
Stage 4 offers the complete package, and once you understand how these components interact, it’s hard to go back and consider anything less.
When you lift a 4Runner more than 2-3 inches, you’re changing the operating angles of every suspension component on the truck. Those changes have real consequences: accelerated wear, compromised handling, and a drivetrain that develops vibration where it once ran clean. The Stage 4 kit addresses all of it. You don’t have to worry about piecing a kit together; it’s all done for you. Do the job right the first time.
Installation Overview
This isn’t a beginner job, but if you’re a competent home mechanic with a lift, hand tools, and a torque wrench, you can get this done over a weekend. Budget two full days to be comfortable. A shop will need about a full day to complete everything.
Front: The coilovers replace the stock struts entirely. Remove the factory strut assembly, transfer over to the new Pro Forge UCAs, and set the ride-height collar on the Acme-threaded body before buttoning everything up.
Rear: The shocks bolt straight in. The panhard bar takes a bit more patience; centering the axle correctly benefits from a second set of hands. The trailing arms replace the stamped OEM units and need the same care. The end links are a quick swap.
After Install: Get an alignment immediately. The UCAs change caster and camber, and driving on a misaligned front end will eat your new tires fast. Make sure you’re going to a shop with experience with lifted trucks. It makes all the difference.
Note on ride height: the Acme-threaded body allows plenty of ride-height adjustment, a real advantage over spacer-based lifts. There’s a small catch, though. Adjusting the suspension requires a specialized tool that is sold separately. Would be great to see this included.
On-Road Impressions
I’ll be honest, Ironman’s reputation for building superior suspension components had me going into the install with very high standards. Despite that, the on-road comfort on this kit far exceeded my expectations. Sure, I expected it to ride well off-road. I did not expect it to be this comfortable on pavement.
The 5th Gen 4Runner’s stock suspension is notoriously soft and wallowy, especially out back. The Ironman kit tightens up the notoriously soft and washy suspension without making the truck feel stiff or punishing. Body roll through sweepers is minimal for a truck sitting on a 3″ lift. The truck feels planted and confident at highway speeds. Road buzz ticks up marginally over stock, but it’s not something that would bother most people on a daily drive.
The Panhard bar makes a big difference here. Without it, a lifted Runner sits with the rear axle slightly off-center, and you feel it as a subtle drift on crowned pavement. The Ironman adjustable bar corrects that. The rear tracks exactly where it should, every time.
The adjustable trailing arms take care of the pinion angle situation, and the result is a drivetrain that runs dead clean at highway speeds. There’s no vibration, no harmonic complaint, loaded or empty. After 15,000 miles, it’s still the same.
Off-Road Performance
Vermont & The North Maine Woods
Vermont’s trail systems don’t forgive weak suspension. Rigid rock gardens, off-camber approaches, and uneven entry angles have a way of exposing every shortcoming fast. The Stage 4 kit handled it all as a cohesive system, keeping the truck settled and predictable where lesser setups get squirrely. Planted on the rocks, composed in the mud, and confidence-inspiring when the chassis was fully loaded on a sketchy, off-kilter approach. It didn’t even flinch.
Multiple punishing runs across North Maine’s rutted gravel roads, river crossings, and long stretches of rough two-track for hundreds of miles have tested the extended limits of this suspension. Day after day, no matter the condition –punishing rains, scorching heat, frigid mornings, and even snow- the suspension showed up ready to work.
Overland Comfort For Miles (or kilometers)
The James Bay Road runs roughly 620 kilometers north through Quebec to the shore of James Bay. It is unpaved, corrugated, and completely unrelenting. I was loaded for a multi-day expedition: rooftop tent, awning, 7-gallon water tank, fridge, 7 days’ worth of food, camping gear, and ten gallons of fuel, the works.
The truck covered the full length without a single squeak. Hours into the corrugated gravel, the shocks were still performing without any hint of fade. Ironman attributes this to the aluminum monotube body’s significantly better heat dissipation compared to steel. Cheaper shocks fade on roads like this.
The Pro Forge Upper Control Arms (UCAs) were a highlight, specifically here. Stock UCAs bind under lift and will eat through ball joints. The Ironman forged units moved freely through their full range across every single kilometer. After 15,000 miles, the ball joints still show zero play. Nothing cracked. Nothing loosened. Nothing leaked.
What Could Be Better
No kit is perfect, so here’s my honest take on the shortcomings:
Documentation is functional but thin. The ride height setting procedure, in particular, could use a clearer explanation for first-time builders. Ironman’s online resources and the 4Runner community forums fill the gap, but that information would, for me, ideally be in the box.
Spring rate selection is a bigger decision than the marketing materials let on. A heavily loaded overland rig running medium-rate rear springs will ride low and soft. If you’re building a truck that’s going to be loaded consistently, seriously consider upgrading to medium-plus or heavy rear springs. Know your use case before you order.
Suspension adjustment requires a specialized part that must be purchased separately.
Final Thoughts
I’ve put 15,000 miles on this kit across the James Bay Road, the North Maine Woods, the Swisha Loop, and more Vermont trail days than I can count. The Ironman Stage 4 IM2.5 has handled it all with style and grace. It’s incredibly capable off-road and surprisingly comfortable on the road, and that combination is genuinely rare in an aftermarket lift at this price point.
If you’re looking for a kit for your daily driver that can take you from rugged trail to fresh pavement and everything in between, this kit needs to be at the top of your list. Buy the complete Stage 4 package, spec the right spring rate for how you load the truck, get a proper alignment, and go find some roads worth driving. The suspension won’t be what holds you back.
