4WD Suspension Lift
Your average four wheel drive leaves the factory with fairly compliant suspension and underbody ground clearance that makes entering and exiting the vehicle comfortable while still managing to handle reasonably lumpy terrain.
Exceptions are the more work like Patrol and Landcruiser 4x4 utilities - with beefed up suspension and taller than average ride height. Manufacturers know that the majority of these vehicles spend their lives in mining and agricultural environments and that your average station owner will have no hesitation loading a tractor on the back and driving through a 6 foot deep creek.
The trade-off, when travelling unladen, is a stiff ride and a fairly sharp response from the suspension components.
Why Increase Ride Height?
As we mentioned, many 4x4 daily drivers (i.e.: shopping carts) spend most of their lives as regular family wagons, dropping the kids at school and running around town with the occasional beach fishing expedition thrown in. More ground clearance in this situation just means more inconvenience getting in and out.
Take the same vehicle into some really gnarly terrain with big rocks and drop off's or deep, undulating sand and the benefits of a bit more ground clearance quickly become obvious.
Creeks, wash-outs, large ruts and sand hills immediately become easier to navigate with the tendency to bottom out or 'belly' greatly reduced. Just a couple of inches additional clearance makes a vast difference to the potential of having the car stuck and see-sawing atop a hill.
Another positive is the ability of a vehicle to maintain normal ride height when loaded.
Throw 4 people, mountains of camping and holiday equipment and hitch up a boat or caravan and the suspension quickly levels out under the added weight.
A fully loaded 4WD, packed to the rafters with all the associated holiday paraphernalia really taxes the parts of the car designed to create a comfortable ride - the springs and shock absorbers.
If you are considering increasing ride height through a suspension lift it's probably a good time to ask yourself how much additional weight you want to carry and if the suspension components could use 'beefing up' at the same time.
Much like the Landcruiser or Patrol utes which become much better highway cars under load, stiffer suspension in heavily loaded passenger 4x4's makes for a better handling car with greater levels of comfort.
a pair of 50mm coil spring spacer blocks ‣
There are two common methods for raising the ride height of a 4WD. We're not talking above the massive lifts seen in competition style 4WD's but your common, garden variety, all round 4x4.
The cheapest and easiest method of achieving a suspension lift is to add 'blocks' between the springs and the body of the vehicle.
These can comprise machined neoprene or aluminium spacers for coil springs and extended spring shackles for leaf springs.
These methods do very little but raise the underbody height of the car by the same thickness as the spacer. In theory they shouldn't alter the ride characteristic of the original suspension dramatically except to raise the vehicles centre of gravity. The car may exhibit a little less stability when cornering.
The use of blocks or 'body lift' kits are generally done for aesthetics and appearance rather than performance considerations. It can also facilitate the fitting of taller tyres.
The second and preferred method is to upgrade the springs to taller and potentially stiffer units. Depending on the vehicle and the desired 'lift' height this may necessitate the use of extended shock absorbers, longer brake lines, upgraded shackles and 'u' bolts and various other components.
Providing professional advise and components are resourced this second method should provide a properly balanced and usable upgrade to your 4x4's suspension. Ground clearance and load carrying capability will be increased with a potentially better ride. Bear in mind that 'stiffer' suspension components will probably result in a firmer ride when travelling unloaded.
How Much Lift?
50mm or 2 inches is the maximum we lift any of our four wheel drives. In 2009 the New South Wales Government introduced legislation requiring engineering compliance to accompany any lift greater than 50mm. Our experience suggests that this is about all that is required to enable a car to tackle difficult terrain while maintaining a good level of practicality and servicability. Any higher than this generally requires extensive and expensive modifications to related steering and axle components.
We're also not huge fans of the sensation extreme lifts generate of a very high centre of gravity. Perch a tall 4WD like a Troop Carrier atop super tall suspension and load up the roof rack with a few hundred kilograms. You begin to get a very unstable car when cornering or picking along sloping ground.
(image: a 50mm Coil Spring lift supplemented by air bags ↑)
Air Bag Suspension
Air bags can also accompany a suspension lift and provide additional load carrying capacity but also the ability to control ride height and suspension 'firmness' through the addition or removal of air. These systems can be as simple as a regular tyre valve to onboard compressors that, with the press of a button, adjust the airbags according to need.
The choice of 4WD suspension lifts and whether or not to add one to your car will always come down to a compromise between ride comfort and practicality.
Taller suspension is definitely a bonus off road, where the ability to crawl over larger obstacles can be the difference between getting stuck or moving on.
Heavily laden four wheel drives benefit from increased lift with additional load carrying capacity and better handling. All the positives of increased ride height become apparent as soon as you unhook the caravan and start investigating what's over that rocky gutted hill.
Bear in mind that the new, heavy duty suspension won't be as comfortable as the old springs when you're travelling without a load.
Read more about leaf spring suspension here.
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