Leaf Springs

Concept / Function

It is made of one or more overlapping plates of steel that work as an elastic suspension element for vehicles.

Their function is to absorb the impacts caused by surface irregularities and to support the weight of the vehicle, guaranteeing comfort and height. In trucks, buses and pick-ups they also have the function of ensuring the connection of the axle to the chassis.

Types of leaf springs

*Note: "RATE” is the Spring rigidity measurement. The higher the RATE, the more rigid (harder) the spring will be.

Linear action leaf springs
They are characterized by having a single RATE (constant / elastic) over the entire operating range. They are used on the axle where load variations are not expressive.

The term “Linear Action” is used because its operation is expressed in the form of a straight line.
Progressive action leaf springs
They are characterized by a variable RATE (constant / elastic), a smooth (soft) start and a stronger (more resistant) end. The shifting from one RATE to another is carried out progressively as the applied load is increased.

They are used in the rear end of most vehicles where load (weight) variation is significant. This concept provides greater comfort to the empty vehicle and more resistance when it is loaded, affording greater drivability.
Types of progressive leaf springs
Support Leaf Springs

Shifting from one phase to another is carried out smoothly, according to the load being applied.

Linear action with the auxiliary leaf springs

Shifting from one phase to another is carried out at once, according to the load being applied.

Support and Auxiliary Leaf Springs

Used when there are large load variations.

Leaf spring configuration

Multiple trapezoid-shaped plates

The stress is distributed along the stacked plates.

Parabolic Leaf Spring

They are produced using state-of-the-art technology. Thickness varies along the plate profile. This thickness is proportional to the strength applied at each end of the plate.

This configuration permits the use of fewer plates, or even a single plate, in leaf spring construction, thus reducing its weight and guaranteeing load capacity and durability that is identical to a multiple trapezoidal plate leaf spring.

It also provides less or no attrition between plates thus eliminating noise and providing greater comfort.

Air Link

Plate or set of plates with parabolic leaf spring with characteristics that allow direct assembly of the air bag in pneumatic suspensions.

Suspension Components

Fabrini has equipment that permits the production of special suspension parts according to design and customer specifications.


Polyurethane stopper

Wear plate

Support for stabilizing bar

Anti-noise stopper

Stopper with support for stabilizer bar

Special Parts

These parts are produced with or without heat treatment, shot peening, and are painted or oiled.

Original Technology

All RNA springs, either byFabrini or NHK brands are tested, identified and packaged, going directly to the assembly lines of the main automakers in Brazil and overseas. Their quality is ratified, approved and certified by the strictest quality assurance systems, such as the ISO/TS 16949:2009.


The quality of Fabrini springs as Original Parts is also recognized in the spare part market, where they are known as “The original spring.” In order to aggregate more value to its products and its customers, Fabrini offers a service and solution package that ensures the correct maintenance and replacement of suspension springs through the training of independent repair professionals and professionals from cargo and passenger transportation companies.

Today, most vehicles in Brazil circulate with the comfort and safety of springs manufactured by RNA and marketed under the Fabrini and NHK brands, a guarantee of top performance and durability.

This is RNA, the largest manufacturer of original springs in South America.

Development and production

Pioneerism took RNA to the leadership

The excellence achieved by RNA in the development and production of springs in Brazil is evidenced in the pioneering, innovation and leadership in supplying springs to the domestic automobile industry, encompassing passenger and light commercial vehicles equipped with coil springs and pickups, trucks and buses equipped with leaf springs.

RNA has an installed production capacity of approximately 5 million coil springs and 85 thousand tons of leaf springs per year, totaling more than 1000 constructive models, from the conventional leaf spring to the parabolic type and finally the new mixed suspension systems (air + metal), destined to the heavy vehicle segment. Coil springs with linear and progressive action, the latter with cylindrical, conical and biconical constructions are manufactured to supply to the light, average, motorcycle and braking system segments. This broad product line allows RNA to fully meet to the needs of the manufacturer, spare part and export markets.