History of the Horst Link / Four Bar Linkage

Chapter 2

It's always a bit intriguing to figure out what is the next step in innovation for AMP-Research. One such mystery is the termination of the US-patent of the Horst-Link. It's interesting to say the least and the concept of this particular design shaped and produced by Leitner himself, is what really put his vision of a much larger company on the market. The link concept is the composition that actually opened up Leitner's ingenuity and set into motion the direction of a unique and triumphant company by the name of AMP-Research.

This specially designed link is currently under the jurisdiction of Specialized and approved for use by other manufacturers. It was designed by Leitner and is respected by many the world over. It is thought to be the instrument that transformed full-suspension mountain biking after being introduced during the end of the 90s. In fact, it is still utilized at length on everything from cross-country racing bikes to all out downhill-rigs. The four-bar-suspension system is possibly the most popular suspension-system used on "genuine" mountain bicycles, and utilized almost entirely by European mountain bike producers.

It was revealed in the previous chapter how motocross legend Horst Leitner has always been an innovator and visionary. His motor sports enterprise, "ATK," was the leader in numerous smashing developments in motorcycle-suspension, transmission, and braking in the 80s. The 90s brought in the era of the successful mountain biking craze. With Leitner himself grasping the idea of the sport, and applying what he previously learned from motocross, he applied his engineering knowledge, though it was challenging, to this pioneering two-wheeled sport.

Afterwards AMP-Research was responsible for an abundance of ground-breaking products. However, before getting into the beauty and particulars of the link invented by Leitner, also known as the Four-Bar-Linkage. This was a very difficult feat before and something that Leitner himself managed to conquer.

The means by which individuals generates power on a bicycle is in beats. Most people believe that when they pedal a bike it is a single continuous circle; however, there is a definite variation within that circular movement. As a result, cyclical tension is produced on the chain. This is the first dilemma. Much as we love to utilize one speed on a good steep climb, it's not too practical and gears are certainly necessary. While shifting throughout the cassette and the chain- rings, the slant of the chain alters. This changes the "chain-force-vector," which is basically the place where the chain tries to increase its power by pulling.

If the rear-axle is a segment of the main swing-arm as with the single-pivot styles, the position of the turning mechanism in relation to where the chain inserts into a particular chain-ring is vital. The course that the rear-axle traces, as the suspension compresses, is a straightforward arc on single-pivot bicycles. Even if the arc shifts up-and-back or up-and-forward, it is the function of the turning position. If the turning motion is over the chain-ring the rider is on, the chain-force will try to pull the back wheel down, locking-out the suspension. If the pivot is under a particular chain-ring, the chain-force tries to haul the wheel upward, constricting the suspension. Each of these circumstances leads to a considerable sum of a pedal-activated bob, making the suspension react awkwardly under pressure. This is the second dilemma.

The next dilemma was to discover a way to separate suspension movement from braking-forces. Many earlier full-suspension creations lacked what is known as "brake-jack," or a strengthening of the suspension whenever brakes are utilized. This is particularly defined when braking while riding through technical territory, a clear drawback when mountain biking.

Subsequently, this unique link by Horst comes along to save the day. Horst understood the way a rear-suspension design needed to function in order to separate suspension activity from chain-force and the associated consequence of braking. One has to de-couple the rear-axle from the primary swing-arm. Leitner essentially gave the swing-arm a working joint! By positioning a pivot modestly before and a tiny bit under the rear-axle, this innovative link opened the way for an axle that was no longer dependent on following a simple arc. It can track literally straight-up and down as the suspension condenses, lessening the influence of chain-force, and as a result the brake-jack, on the rear axle. Here is a view of the authentic patent operation:


The Horst-Link was utilized on bikes for a number of years prior to selling the invention to another company. The new proprietor of the Horst-Link integrated the design in to their Future-Shock-Rear collection of full-suspension bicycles. It has been the basis of their off-road product collection since that time.

Due to the many advantages of the design, additional manufacturers have compensated Specialized-Bicycles for licensing cost in order to utilize the Horst- Link on bicycles produced for the United States market. Less well-known manufacturers, or those who prefer not to pay a licensing charge, have tried their best at creating knock-offs, and a few of them have actually succeeded! However, the expiration of the "Four-Bar-Linkage" patent makes the contraption available to anyone everywhere, and the effect it will have on this fantastic invention is still unclear. Yet, what is undoubtedly certain is that Leitner will be memorialized as an authentic pioneer, and an innovator who took on a challenge and made it work. This is what is meant by "overcoming the odds!"

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