Summer trip suspension 101
Kiwis love hitting the ‘Great Outdoors’ over summer so we asked specialist supplier ARB for some handy hints regarding your 4x4’s suspension.
There’s a reason why so many people throughout the world load up the 4WD and disappear for a few weeks on the tracks – it’s great fun. However, over the years there have been a myriad of stories regarding keen 4WDers who’ve had a rough time because of poor suspension set ups. From adventurers who have been fined for exceeding their GVM to four wheelers who limp into workshops with sagging springs and aching spines, the biggest factor to consider with regard to 4WD suspension performance is load carrying ability.
No easy task
Everyone knows that 4WD suspension is complex. Old Man Emu. For instance, has four full time engineers who focus solely on developing fully integrated suspension systems that deliver the maximum benefit in ride quality, handling and load carrying ability. Lab testing, scientific data logging and extensive real world testing, encompassing multiple load scenarios, are undertaken to ensure optimal suspension performance in any terrain.
How DO you choose?
When travelling in remote areas, the need to carry sufficient fuel, water, vehicle spares, safety equipment and general supplies invariably means that your 4WD will be
fully loaded, placing significant strain on suspension components. With multiple kit options available for most vehicles, it’s extremely important that the appropriate springs are chosen to match your individual load carrying requirements, as even the best aftermarket springs will produce a poor ride if loaded above ( or too far below) their designed rating. Incorrectly selected springs which are not rated to carry heavier loads will typically exhibit problems experienced every time you drive, including poor ride height, reduced vehicle stability and spring sag over time. An overloaded vehicle often has to be driven at a much slower speed in order to prevent ‘ bottoming out’ on the bump stops. This occurs when the suspension system cannot adjust rapidly enough to handle both the excessive weight and the terrain. Bottoming out makes for an uncomfortable and unpleasant drive and places extra load on other suspension and structural components of the vehicle, which increases the chances of a breakdown further down the road.
Reduced working life
Too much weight will also make the shock absorbers work harder than necessary, resulting in fatigue and reduced comfort, handling and control. As well, continued overworking of the shocks reduces their working life, resulting in increased costs through the need for more regular replacements. Loss of ride height is another consequence of an overladen vehicle. Off road travel regularly requires good approach and departure angles in order to successfully overcome obstacles, and the reduction of ride height can mean the difference between climbing a steep rise and turning back the way you came. If you rarely travel off road but are now planning a big adventure, consider upgrading your springs to those with a heavier rating. Having the right springs fit ted to your vehicle will ensure your suspension system exhibits better towing and load carrying characteristics, improved wheel articulation and increased ride height. Put simply i t will ride and handle better over any road surface.
Correct loading
Roof racks are great for carrying light and bulky items such as swags, firewood, camping equipment and gear that has started to get on the nose, like last week’s socks and jocks. Still, it ’s important to spread the load evenly across the roof rack and to secure all items tightly, as a shifting load can cause your vehicle to suddenly veer out of control. Heavy i tems should be avoided on roof racks. A top- heavy vehicle becomes dangerously destabilised, particularly at high speeds, and t ypically takes on a disconcerting swaying motion that makes driving a hairy experience. Aim to keep heavy items down low, either in a trailer or, if you’re transporting them
within your vehicle, over the axle, towards the centre of the vehicle, or evenly distributed on both sides wherever possible. Avoid heavy loading toward the front of the vehicle, as this will cause the vehicle to ‘ dive’ every time you hit the brakes. Likewise, concentrating too much weight in the rear of your vehicle will make the steering feel light and vague and can also result in misaligned headlights. So, keep the centre of gravity within your vehicle as low and as wide as possible to ensure a safe drive in any terrain.
Gross Vehicle Mass (GVM)
Your GVM is the total weight of your vehicle plus any accessories you have fitted and the load your vehicle is carrying ( including passengers and fuel). Keeping within the GVM limit ensures you can safely and legally carry all the gear needed for your off road adventures without voiding your insurance in the event of an accident. Therefore, knowing the GVM of your vehicle and how much weight you have both on and in your vehicle is paramount. The fitment of accessories such as bullbars, winches, canopies, roof racks and auxiliary tanks permanently affects a vehicle’s gross mass, and when you head off road, additional items such as camping equipment, sufficient food and water plus passengers all add to the weight.
Be prepared
The key to any great off road trip is to be prepared. Don’t wait until you’ve already hit the road to start thinking about your load carrying requirements. An appropriately selected, integrated suspension system delivers tremendous improvements in ride, comfort, handling and load carrying ability that are felt every time you drive.