Wheel articulation, also called vehicle articulation or axle articulation, is the vehicle’s ability to allow its wheels to independently move vertically. Wheel articulation differs from wheel travel, the range of motion of one wheel to move vertically, which is determined by the suspension or shock absorber’s range of motion.
Vehicles with good wheel articulation must indeed have a fair amount of wheel travel. So, what exactly is wheel articulation? Wheel articulation refers to the vehicle’s ability to keep both wheels on an axle firmly on the ground even when one wheel is extremely elevated and compressed.
One way to determine whether your vehicle has good wheel articulation is through a Ramp Travel Index (RTI) test. At the RTI ramp, the vehicle drives one tire up the ramp until the point when one of the other tires starts to lift off the ground. The score is determined by measuring the distance the vehicle traveled up the ramp at the center of the wheel. This number is divided by the vehicle’s wheelbase and then multiplied by 1000.
Most stock SUVs have a decent score of around 400 to 600. Meanwhile, models like the 2-door Jeep Wrangler have good articulation with a score of 820.
Having an articulating suspension is important because it allows trucks, SUVs, or any off-road vehicle to have traction on uneven terrain or over obstacles like roots, rocks, and mounds.
Just like driving around a track, a vehicle’s wheels must be firmly placed on the surface to have traction and stability. A vehicle that has good suspension articulation can keep the wheels firmly planted on the surface even when one wheel on the other side of the vehicle is going over an obstacle like a rock.
If the wheels aren’t firmly on the surface when the vehicle goes over rocks, roots, or uneven surfaces, then it won’t be able to traverse the terrain effectively. The vehicle’s ability to accelerate, maintain its path, and brake will be hampered.
One aspect that makes off-roading exciting is the fact that you’re traversing challenging terrain with your vehicle. Whether this is steep inclines, uneven trails, rocky paths, river crossings, or deep mud, traction is important. Otherwise, your vehicle can get stuck, slide, or even tip over.
A suspension with good wheel articulation keeps the wheels in contact with the ground, allowing the wheels to always have grip.
If a vehicle has good traction, then it’s generally more stable. A stable vehicle will be more responsive to driver inputs and will maintain its intended path, being less susceptible to slides and other disturbances.
Good wheel articulation distributes the vehicle’s weight uniformly, decreasing stress in any one area that might damage the chassis, axles, or suspension components.
Driving a vehicle that has poor handling characteristics can be quite stressful. You don’t know what the vehicle will do if it drives over challenging terrain. A vehicle with good articulation and better grip will instill more confidence since you won’t need to constantly worry about slipping or damaging the vehicle.
An off-road vehicle’s suspension system is mainly responsible for good wheel articulation. Components like springs, shock absorbers, and control arms work together to absorb stress from uneven ground while also allowing the wheels to travel freely up and down.
A suspension’s arrangement and design influence how the wheels move vertically whenever they encounter uneven terrain. Off-road vehicles can have a solid axle or an independent suspension, with each design affecting wheel articulation differently.
A solid axle connects the front and rear wheels, creating good articulation and flex because as one wheel moves up or down, the other wheel on the same axle is pushed to move. If one wheel runs over an incline, the other wheel will also push itself upward. Meanwhile, if one wheel hits a rut, then the other wheel will also similarly lower itself. Solid-axle suspensions allow vehicles like trucks and jeeps to traverse uneven and challenging terrain at slow speeds.
An independent suspension means each wheel can move independently of each other. Most modern SUVs have these systems because they offer better handling characteristics and ride comfort on conventional roads. In independent suspensions, the roll bar is the only connection between the left and right sides. It compresses the outside wheel in a corner to prevent the vehicle from rolling over.
Wheel articulation’s importance can’t be understated when it comes to traversing challenging off-road terrain, but other off-road abilities are also important. These include having a high ground clearance, a good set of wheels, and a capable 4×4 drivetrain.
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