Products

Lesjöfors offer a comprehensive range of Standard and Heavy Duty Leaf Springs, commonly used in the suspension systems of 4x4, Light Commercials and some passenger cars. Featuring over 200 parts covering more than 70 different models. Most Lesjöfors Leaf Springs supplied fully bushed and ready to fit. Complete range of U-Bolts available for both Standard and Heavy Duty applications. Springs manufactured to OE matching quality. Both Parabolic and Multi-leaf Springs available.

There are two types of leaf spring used for vehicles; the multi leaf and the parabolic leaf spring.

The multi leaf spring design is based on the use of a flat trapezoid geometry, with cut leaves stacked one on top of the other. This leads to a multi leaf design with different lengths of each leaf. When a multi leaf spring deflects the leaves move relative each other. The contact between the leaves produces a friction between them, which leads to a difference in load between compression and decompression. The longest leaf has two eyes for assembling to the vehicle body. The strength of this leaf and the eyes are critical and sometimes the second leaf will have safety loops which hook around the main eye as a back up in case of failure. The centre of the spring is normally fixed to the vehicle axle with U-bolts.

The parabolic spring is designed for low internal friction and lowest possible weight and consequently has fewer leaves. The leaves are partly given a parabolic shape from the centre to the end of the leaf, which gives an equal bending stress level along the parabolic part. This ensures efficient use of material and minimum weight. The shape of the leaves is such that contact between the leaves only exists at the centre and the ends. And since the centre of the leaf spring is fixed to the axle with U-bolts, the only friction comes from the end contacts. Rubber pads are also sometimes used to lower the friction. As with multi-leaf springs, the strength of the eyes is a critical safety factor.

Manufacturing of leaf springs can be divided in to three broad areas: - Preparing leaves - Bending - heat treatment - shot peening - Assembling - presetting - surface treatment

Leaves for multi-leaf springs are prepared by cutting and stamping whilst parabolic leaves are hot rolled in a purpose-made rolling machine. The ends of the main leaf are heated and the eyes are then hot rolled. The leaves are heated and individually bent to the correct arc radius and, whilst still clamped between the bending tool, each leaf is quenched in oil to receive high strength and the correct shape. Parabolic leaves also have an arc radius but are however normally straight in the thicker central section. The leaves are finally tempered for high material toughness and strength.

After cooling, the shot peening process is necessary for all parabolic leaves. For multi-leaf springs however, it is normally only the two safety-critical leaves that require shot peening. The bushes are pressed into the eyes and the stack of leaves assembled. Positive stresses are then introduced into the spring by a pre-stressing process.

The multi leaf surfaces are protected against corrosion by painting of the outer surfaces and by lubrication between each leaf. Parabolic leaves are individually painted on all surfaces.

The manufacturing plants management systems are certified according to the quality assurance standard EN ISO 9001 and the environmental standard ISO14001 both third party approved.

Lesjöfors have a full range of boot and bonnet Gas Springs ready to go from stock! Over 1,500 different parts for a large variety of European and Asian applications. All springs supplied complete with end fittings for ease of installation.

Stock availability consistently over 98%. All gas springs are manufactured to OE standards and stocked for worldwide distribution. Lesjöfors produce a comprehensive range of OE matching quality gas springs, and our current catalogue features over 1000 part numbers, most complete with end fittings and covering almost every European & Asian vehicle.

There is a common misconception within the automotive industry that OE replacement gas springs are only available from main dealers. This is no longer the case, with a fast-growing range of matching quality gas springs available throughout the aftermarket.

It is important for technicians and mechanics to understand the design & manufacturing process in order to quell any misconceptions the customer may have and communicate the benefits of aftermarket gas springs.

A gas spring is made up of a steel cylinder filled with nitrogen gas under high pressure; a small amount of oil, a piston, piston rod, seal and end fittings. The function of an automotive gas spring is to support the opening and closing of the vehicle's boot or bonnet. This aids the elevation, holds the weight once open & allows for a controlled close.

The piston inside the gas spring is designed in a special way such that the upper side has a larger surface area than the underside, causing the gas pressure to force the piston and rod out to maximum stroke.

In use, there is a load forcing the piston inside the cylinder. Once this is released, for example when a boot latch is opened, the force is overcome by the nitrogen pressure on the upper side of the piston leading to extension of the spring. The piston areas and gas pressure are specifically designed for each application depending on the weight of the vehicle's tailgate, for example, to give the required spring load and deflection performance. The speed is controlled by the piston channel size; and the speed reduction near to maximum opening is assisted by the use of a small amount of oil in the cylinder to give a damping characteristic towards full extension. All new gas spring products are endurance tested for life time assurance.

Gas springs are manufactured from several components. The tubes are manufactured from pressure vessel steel with very high demands on inside surface smoothness. Piston rods are manufactured from finely ground and polished steel bars. The rod surface is either chrome plated or nitro-carburized to ensure high hardness, highest corrosion resistance and best possible wear resistance. Rod guides and gaskets are made from special, wear resistant materials.

After assembly, the spring cylinders are painted with a paint containing corrosion inhibitors for high resistance against corrosion. The gas spring is then filled with Nitrogen gas using a technique which assures high pressure accuracy. The springs are load, deflection and speed tested before delivery and each spring is marked with an identification and part number.

The Lesjöfors gas spring design system was accredited in 2005 to ISO/TS 16949 2002 standard. The gas springs are manufactured by Lesjöfors and Hanil Precision joint venture company, Lesjöfors Gas Spring LV, according to ISO/TS 16949 standard. All manufacturing fulfils the demands of environmental standard ISO14001:2004.

Due to the high and constant pressure within the chamber, gas springs have a maximum life span, shortened by the regular movement of the piston and exposure to the elements.

There are also several external factors which can cause a gas spring to fail! Dirt and other external particles can build up on the piston rod while extended, which are then mixed with the nitrogen and lubricating oil once compressed, leading to slight defects in the chamber seal. Once the seal has become worn or damaged, nitrogen and oil are allowed to escape, reducing the force of the spring and resulting eventually in complete failure.

Additionally, whilst the end seals are made from a special kind of rubber, they will naturally age and degrade over time, and Lesjöfors therefore recommends that stockists operate a 'first in, first out' policy.

Lesjöfors offer an extensive range of over 800 complete sport spring kits. Lesjofors sport springs will safely lower your car by up to 50mm, substantially improving road holding and providing a sportier driving experience.

Most Lesjofors sport spring kits are TÜV compliant, ensuring the highest levels of safety and performance. Every kit is designed to be fitted with the original shock absorbers. Gas shock absorbers can however be used to further enhance the ride. Lesjöfors sports springs will safely lower your car by up to 50mm, substantially improving road holding and providing a sportier driving experience. Every kit is designed to be fitted with the original shock absorbers, but gas shock absorbers can be used to further enhance the ride.

Lesjöfors Sports Lowering Spring kits are designed to lower a car by as much as 50mm, to provide a sportier driving experience. By lowering the car's centre of gravity and increasing the stiffness of the spring, road handling is substantially improved. Lesjöfors Sports Springs are designed with a high degree of accuracy using specialist design software developed in-house.

Lesjöfors Sports Springs lower the vehicle by between 20 - 50mm, which is considered moderate by some. However, Lesjöfors Sports Springs are designed for a sportier driving experience rather than purely for aesthetic purposes. Springs which lower by more than 50mm often reduce or eliminate the spring travel distance, negatively affecting spring performance and creating problems coordinating with standard or gas shock absorbers.

Lowering a car's centre of gravity and increasing the stiffness of the springs reduces body roll, making the car stick to the road while cornering. 'Nose dive' caused by braking and 'squat' during acceleration are also reduced.

Springs have been manufactured at Lesjöfors since 1852 and today Lesjöfors is the largest manufacturer in Europe for aftermarket chassis springs. Lesjöfors' state of the art factory is designed to meet the demands of quality, flexibility and environment for many years into the future.

Every spring is manufactured from high quality spring steel. Depending of the design, oil-quenched or unquenched wire is used. When oil-quenched wire is used all springs are stress relieved directly in line after the coiling process. Springs manufactured from unquenched wire are quenched and tempered after the coiling operation, giving the spring high strength without the need for stress relieving. In both cases the steel will have the same spring quality characteristics.

The wire is cold formed to spring shape in computer controlled automatic coiling machines. When oil quenched wire is used, all springs are stress relieved. This treatment improves the fatigue strength.

Some chassis spring designs have one or both ends ground. At Lesjöfors this grinding is done in special computer controlled spring grinding machines.

All springs are protected from corrosion by zinc phosphate and powder resin paint. This technique gives an excellent protection against corrosion, even if there is a chip or a scratch in the paint surface. It also meets the standards used by vehicle manufactures.

Most Lesjöfors Sport Springs are TÜV compliant. Lesjöfors are certified to the ISO/TS16949:2009 quality management system. This automotive sector-specific quality management system applies to design, development and production of automotive products at Lesjofors.

All coil springs delivered by Lesjöfors are quality assured and manufactured by the company. Lesjöfors only use spring steel material from suppliers who can meet the highest demands for both internal and surface quality. All suspension spring designs are quality verified and manufactured with the best technologies available.

The load and deflection parameters are assured by quality control throughout the production process. To verify that the result is within given tolerances a final load testing of every batch is made before surface treatment, as shown to the right. The load at rebound length, length at kerb weight, load at bump length and the spring rate are the most important measurements.

Surface treatment is made with an advanced zinc phosphate system method, which together with powder paint ensures galvanic protection against corrosion, and a good cosmetic finish.

The large number of spring products in the aftermarket and the importance of identifying the correct product make identification labelling very important. To guarantee the most accurate and secure identification of the spring the ID number should follow the spring through the manufacturing process.

At Lesjöfors, each spring is clearly identified from the first production step until the inkjet identification number is applied to each single spring in the painting line.