In the off-road world, few words get thrown around more than flex.
Photos of a Jeep twisted across a rock ledge… tires stretched to the limits… suspension working at full extension… that image has become the symbol of off-road capability.
And for good reason.
Articulation keeps tires on the ground.
And when tires stay on the ground, vehicles maintain traction, control, and stability.
But after more than 12 years running Corner Travel Index (CTI) tests and recording over 14,000 individual vehicle measurements, one thing has become very clear:
Not all flex is created equal.
At MetalCloak, CTI testing isn’t just a demonstration. It’s a long-running research program that has directly shaped the suspension systems we build today. In fact, we’re the only suspension company in the industry with a dataset this large… gathered across thousands of vehicles, from stock builds to fully modified trail rigs.
Those tests have taught us a lot about articulation… what creates it, what limits it, and how to design suspension systems that deliver the kind of flex that actually performs on real trails.
Why Articulation Matters
When a vehicle drives across uneven terrain, each tire encounters a different height and angle of obstacle.
Without articulation, the suspension quickly runs out of travel and lifts a tire off the ground.
The result:
-
loss of traction
-
spinning tires
-
reduced steering control
-
increased rollover risk
Articulation allows the axle to rotate and the suspension to move so that all four tires remain in contact with the terrain.
Trails like the Rubicon Trail or the rock gardens of Johnson Valley constantly force vehicles into twisted positions where articulation becomes critical.
The more the suspension can move while keeping the chassis stable, the more traction the vehicle maintains.
And traction is what keeps a driver in control.
The MetalCloak CTI Program
Over the last 12 years, MetalCloak’s CTI ramp has tested:
-
stock vehicles
-
mild lift kits
-
extreme rock crawlers
-
overland builds
-
daily-driven Jeeps
Every test adds to a growing dataset that now exceeds 14,000 recorded runs.
This massive library of real-world data allows us to analyze how suspension systems perform across thousands of configurations.
More importantly, it allows us to see patterns.
Patterns that reveal what works… and what doesn’t.
And that knowledge feeds directly into the engineering of MetalCloak suspension systems.
What the Data Revealed About Flex
The first and most obvious lesson from thousands of CTI tests is simple:
Articulation matters.
Vehicles with greater articulation consistently maintain better tire contact on uneven terrain.
More tire contact means:
-
improved traction
-
more predictable steering
-
greater vehicle stability
But the data also revealed something deeper.
The suspension systems that perform best don’t just have more flex… they have usable flex.
Flex that happens smoothly, predictably, and without mechanical resistance.
Lesson #1: Suspension Binding Kills Flex
One of the most common reasons vehicles score poorly on the CTI ramp is suspension binding.
Binding occurs when components reach the limit of their movement and physically resist further articulation.
Common sources include:
-
rigid control arm bushings
-
limited joint rotation
-
short shock travel
-
incorrect geometry
When binding occurs, articulation stops… even if the suspension technically still has travel available.
That’s why joint design is critical.
MetalCloak’s Duroflex joints were developed specifically to eliminate this problem by allowing true multi-axis movement without binding.
This allows the suspension to articulate freely while still maintaining the strength and durability required for real-world off-road use.
Lesson #2: Geometry Determines Articulation
Another key insight from CTI testing is that lift height alone does not create articulation.
Two vehicles with identical lift heights can produce dramatically different CTI scores depending on suspension geometry.
Proper control arm angles allow the axle to rotate smoothly as the suspension cycles.
Poor geometry forces components into positions where they begin to fight each other.
When that happens, articulation stops long before the suspension reaches its theoretical limits.
This is why MetalCloak suspension systems are engineered around geometry that supports maximum, usable axle movement… not just increased ride height.
Lesson #3: Shock Travel Plays a Major Role
Shock absorbers are often overlooked when discussing articulation.
But in many CTI tests, shock travel becomes the first limiting factor.
Once a shock reaches full extension, the suspension can no longer droop… even if the rest of the system could continue moving.
Longer travel shocks allow the axle to continue cycling while maintaining proper damping and control.
But travel alone isn’t enough.
Shock valving must also be tuned so the suspension remains stable on-road while still allowing the flexibility required off-road.
Balancing those requirements is one of the biggest engineering challenges in suspension design… and one of the areas where real-world testing matters most.
Lesson #4: Flex Must Work With Stability
Articulation without control can create unpredictable handling.
But properly engineered articulation does the opposite.
A well-designed suspension allows the axle to move freely while keeping the chassis composed and predictable.
This is the balance MetalCloak focuses on:
maximum bolt-on articulation with real-world stability.
Because flex isn’t just about clearing obstacles… it’s about maintaining control when the terrain is uneven, unpredictable, and constantly changing.
That applies both off-road and on-road… where stability is critical for safety.
Lesson #5: Real Trails Demand Real Articulation
A CTI ramp is a controlled testing tool.
Real-world trails introduce additional variables:
-
momentum
-
traction changes
-
dynamic weight transfer
Locations like Moab challenge suspension systems in ways that static tests cannot fully replicate.
But CTI testing provides something incredibly valuable:
a consistent baseline across thousands of vehicles.
And across those thousands of tests, one pattern shows up again and again:
Vehicles with more usable articulation maintain better traction when terrain becomes unpredictable.
Why MetalCloak Focuses on Flex
For MetalCloak, articulation has always been a core design principle.
Because more usable flex delivers:
-
better traction
-
more consistent tire contact
-
improved vehicle stability
-
greater driver control
It allows drivers to move through obstacles smoothly… without relying on wheelspin, throttle, or momentum to compensate.
That’s why MetalCloak suspension systems are engineered to deliver industry-leading bolt-on articulation.
Not for show… not for numbers… but because real-world testing has proven that articulation improves performance and safety.
Turning Data Into Better Suspension Systems
The biggest advantage of running more than 14,000 CTI tests is the insight it provides.
Every vehicle tested adds to a deeper understanding of how suspension systems behave under articulation.
That knowledge directly influences how MetalCloak products are designed.
Over the years, CTI testing has helped refine:
-
joint designs
-
control arm geometry
-
shock travel requirements
-
suspension tuning
The result is suspension systems that deliver the articulation drivers want… while maintaining the control and predictability required for daily driving.
The Future of Articulation
As vehicles continue to evolve, so will suspension technology.
But one thing will not change.
Articulation will always be a core requirement for off-road performance.
The ability to keep tires planted on uneven terrain is what allows a vehicle to maintain traction, stability, and control.
And thanks to over a decade of testing and more than 14,000 CTI runs, MetalCloak will continue to lead the industry in understanding how articulation works… and how to engineer suspension systems that make the most of it.
Flex isn’t just a photo opportunity.
It’s traction.
It’s stability.
And ultimately… it’s control.
And control is what keeps drivers moving safely… both on the road and on the trail.
Key Insights From 14,000 CTI Tests
After more than a decade of CTI testing across thousands of vehicles, several clear patterns have emerged.
These insights consistently appear across builds ranging from stock Jeeps to fully modified rock crawlers.
-
Suspension joints determine articulation limits.
Rigid bushings are one of the most common articulation bottlenecks. Multi-axis joints allow suspension systems to cycle freely without binding. -
Geometry has more impact than lift height.
Control arm angles dictate how smoothly the axle moves through its range of travel. Poor geometry can reduce articulation even on taller lifts. -
Shock travel often caps maximum articulation.
When shocks reach full extension, articulation stops. Proper shock length and valving are critical to achieving usable flex. -
Tire size changes CTI results.
Larger tires increase ramp distance before wheel lift occurs, which can raise CTI scores even if suspension travel remains the same. -
Sway bar configuration dramatically affects articulation.
Disconnecting sway bars allows each side of the suspension to move independently, increasing axle twist. -
Balanced builds articulate better.
Vehicles with balanced weight distribution generally produce more consistent CTI results than heavily front- or rear-loaded setups. -
More usable articulation improves traction and stability.
Maintaining tire contact reduces wheel spin and allows drivers to maintain better control in uneven conditions.
CTI and Suspension Flex FAQ
What is a good CTI score for a Jeep?
Most stock Jeeps score between 400–600 depending on wheelbase. Well-designed suspension systems often exceed 900.
Does lift height increase articulation?
Lift height alone does not guarantee articulation. Suspension geometry, joint design, and shock travel play larger roles.
Why does articulation matter off-road?
Articulation allows tires to stay in contact with uneven terrain, improving traction and stability.
What limits articulation the most?
The most common limits are shock travel, joint binding, sway bars, and suspension geometry.
