The first few off-road trail rides in your new 4x4 didn't present you with too many hassles. Sure, the bull bar has a couple of scuff marks, and the shiny side steps proudly display some dents and other battle scars, but you did manage to conquer most obstacles thanks to their sacrifice. But, there's a thorn in your side: your buddy's ancient Hilux – albeit heavily modified – managed to negotiate those same obstacles without touching its chassis to the ground, and kept all four wheels on dirt in the places where your fancier vehicle had to rely on its diff-locks to get out of a cross-axle situation.
The solution is obvious: you need more axle articulation and extra ground clearance – but how do you go about adding that air between your 4x4's undercarriage and mother Earth? Ideally, you would be able to find a single solution that should take care of your requirements, but things are never that simple. There are various factors at play in lifting your offroader higher off the ground, and they're all interconnected.
How do I get extra ground clearance?
One of the ways to raise a 4x4 is to install a suspension lift kit. This could mean anything from simple spacers between the springs and the chassis, to complete spring sets; with some tolerant budgets even stretching as far as air springs. With a decent suspension lift, you'd gain ground clearance as well as improve the axle articulation (the freedom of the wheels to move up and down, over obstacles and through dips). The nice thing about a suspension lift is that it results in almost the entire vehicle, from the chassis upwards, standing further from the ground. The approach, break-over, and departure angles all improve, giving you the ability to tackle challenging obstacles without snagging the front bumper, side steps or tow bar.
However, there's often a lot more to a successful lifting operation than merely installing different springs or fitting spacers. For starters, the standard shock absorbers will probably not be compatible with the new ride height or with the increased wheel movement that high-riding springs bring. Raising the ride height also increases the risk of altering the suspension geometry outside of its correctable range, which could lead to vibrations or erratic responses while steering and braking. Torsion bars (as commonly used on independent front suspensions) complicate matters even more: they can be set to a higher pre-tension, which increases the front ride height, but doing so often forces them to operate outside their optimal operating range. This results in a reduction in downward wheel travel (droop), a stiffer ride-quality, and increased resistance to upward motion (spring compression).
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