Old Man Emu Springs
Old Man Emu has, by far, the largest range of suspension products available for 4WD vehicles and carries more products for more applications than any other 4WD suspension company.
The diversity of customer requirements, from virtually no load up to excessively heavy loads and the wide spectrum of working environments set the OME engineers the task of designing and developing a range of springs to cover as many applications as possible - including mining, farming, four-wheel driving, touring and towing.
Illustration shows a typical OME spring which may or may not exactly represent the spring for your vehicle.
It is important to remember that a spring supports weight and sets the vehicle ride-height. It determines the optimum limits of the suspension travel and is a major contributor to the vehicle's ride and handling. But a spring cannot operate effectively without a correctly matched shock absorber.
A shock absorber controls the spring, dictates the ride quality and is often used as a stop to limit suspension travel. A shock absorber cannot cure a suspension problem if the spring's characteristics or condition are inappropriate.
Simplistically, the spring provides the flexibility in the vehicle's suspension necessary to ride over uneven surfaces and the shock absorber ensures that this flexibility does not allow the vehicle to bounce out of control.
FEATURES THAT MAKE THE DIFFERENCE
Old Man Emu's Polypropylene greaseable anti-friction pads and graphite-impregnated grease reduce friction and prevent corrosion at the leaf tips, where pressure is the greatest. Without this attention to detail, inter-leaf friction is greater and the ride becomes correspondingly harsher. Attention to detail is a priority and correct furnace temperatures must be monitored throughout the production process if the spring is to survive. Shot peening reduces stress and fatigue by 100% in the leaves themselves, which are diamond cut and draw tapered to ensure correct operation. Loose clamping of the spring clips provides correct control, preventing squeaking and scoring of the tension side of the main leaf and avoiding stress creation. Most OME leaf springs feature the military wrap for heavy duty usage.
STRESS - A MAJOR PROBLEM
The incorporation of flats in the springs reduces the likelihood of sag occurring. A spring without a flat is subject to deflection when curvature is pulled from its center, as it adopts the shape of the flat axle seat.
A spring without a flat has a greater free camber, which requires a greater working deflection and hence higher stress induced by the U-bolts - which leads to sag. Characteristics of sag are lost height, uneven appearance and a spoiled ride.
All OME leaf and coil springs are fully scragged and load-tested to ensure that the finished product meets the required specifications. Scragging is the process of subjecting the spring to a load greater than that which will be experienced in service. This ensures that the spring steel has yielded and adopted permanent curvature.
After scragging, all Old Man Emu springs are subjected to a preset load and checked to ensure that the amount of deflection is within the required limits of plus or minus 3mm.
Note the importance of eliminating stress and friction - which are the keys to ensuring a long and trouble-free working life, even under the worst conditions. The greater operating life achieved by Old Man Emu leaf and coil springs over other original equipment and aftermarket products is testimony to the correct application of spring technology.
ELIMINATION OF SAG
Attention to spring design eliminates 'sag'. Steps during the design and fitting stages will ensure no built-in failures occur. Leaf lengths are calculated to ensure that the spring is as uniformly stressed as possible. Inappropriate lengths will concentrate stress in one particular area and will cause premature sagging or breakage.
The selection of a "two stage' leaf spring, from the extensive OME range, for heavy duty applications will maintain both a good ride and handling when unladen, as the extra spring is not being used. Under load, all the leaves contact each other and provide the required additional support, though the OME suspension system's good ride qualities are still retained.
The less-expensive aftermarket suspension "fixes" of "add-a-leaf" or "reset and extra leaf" have a strictly limited life-span and eventual spring replacement is inevitable.
OME two-stage springs are fully cambered and designed as integral units, so sag is eliminated. There are no cheap fixes to load or ride problems. A "system' is needed, where the spring is designed to relate to the shock absorber. OME supplies just such a system.
It's important to note that a spring can only be reset twice before the steel loses its spring characteristics. The addition of a helper leaf on the bottom of a single-stage spring also has limitations, as it is usually not compatible with the design of the original spring and "picks up" too late to perform the load-carrying function properly.
OLD MAN EMU COIL SPRINGS
All 4WD vehicles are imported into Australia and the manufacturers are sometimes forced to compromise their designs to cater for a world-wide market. The largest market is in the Middle East, where the only loads carried are passengers over smooth highways and sand. This is a vastly different environment from the one encountered in Australia, where a vehicle is subjected to extremes - from unladen highway cruising to severe off-road use, often fully laden, including the kitchen sink!
There is clearly a need for springs which are more suited to coping with this environment, whether the vehicle is laden or unladen.
OLD MAN EMU - PROBLEM SOLVED
As standard original equipment coil springs are prone to sagging (especially at the rear) and therefore cannot satisfactorily carry increased loads, OME designs aftermarket coils to restore the ride height of the laden vehicle.
When matched with OME's specially valve coded range of Nitrocharger shock absorbers, the increased suspension travel results in improved off-road performance, better towing and load-carrying capabilities and enhanced ride and handling characteristics
Old Man Emu coil springs are available in either constant or variable rate to suit the specific performance requirements of particular applications. Manufactured to exacting standards, OME coils are shot-peened for a longer life, fully scragged and load-tested to ensure optimum quality and durability.
Constant rate coils are acceptable on the front of most vehicles, when the correct spring and shock absorber combination is fitted. However, constant rate coils are not acceptable on the rear, as they produce a harsh ride when unladen and a comfortable ride only when laden. For this reason, OME designs variable rate coils which provide both an excellent ride - whether laden or unladen - and the much-needed increased load-carrying capability.
On variable rate coils, the wire diameter may taper for part of the spring length and then remain constant from that point onwards: the tapered section is the first stage of the variable rate spring and provides the ride comfort when unladen. A second method of achieving a variable rate is to vary the coil spring's pitch - pitch being the distance between the individual spring coils.
Regardless of your vehicle choice and its original equipment suspension specifications, OME can supply a suspension system that will transform the ride and handling characteristics, both on and off the road. Fitting a OME Nitrocharger shock absorber and leaf or coil spring system will instantly result in improved towing capabilities, an increased load-carrying capability, enhanced off-road traction and excellent on-road comfort: these are the benefits to be enjoyed with an OME durable suspension package. Forget the production-line compromises, as there is an alternative to that harsh ride, sagging suspension and poor handling - Old Man Emu.
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