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The English version of the articles published by the staff of Safe Riders and our friends and collaborators. Safe driving but also technique, bike tests, insights and fun. Enjoy reading!

Full Floater Suspension Systems

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Intro

When I tested the BMW S1000XR, I noticed from the specs that the bike is equipped with a rear suspension called Full Floater Pro. I already knew the name Full Floater because it is a progressive damping suspension widely used by Suzuki in the 80s. Now, BMW tends to call “Pro” a lot of things that others also do – for example, the ABS Pro is nothing more than an anti-lock system with cornering function – so I distractedly thought that this suspension name was something like that and I mentally filed it in the “advertising fluff” drawer. 

Later, I also tried the S1000R, based on the same mechanics, also common to the super sports S1000RR, but this time I was struck by this phrase in the press release, which had escaped me before:

The spring strut with Full Floater Pro kinematics is now located significantly further away from the swing axis and the engine. This prevents the engine from heating up due to waste heat and ensures even more stable temperature behaviour and even more constant damping response.

In fact, in a visual comparison between the old and the new version, the shock absorber, which was previously practically hidden by the frame in the side view, now stands way back.

The full floater system as I knew it has several advantages but keeps the shock absorber ordinarily close to the engine. I absolutely had to understand, so I dug deep and found a lot of interesting information that I decided to share in this article. Enjoy!

A Bit of History

Starting from the ‘70s, the manufacturers of dirt bikes were faced with the problem of how to make landings less dramatic after jumps that, with the growth of bikes’ power, were becoming high enough to smash the frames—and also the drivers. It was essential to increase the wheel travel first. The simplest move would have been to adopt larger shock absorbers and stronger frame, but the weight gain would have been unsustainable.

A solution came from the Yamaha Monocross system, introduced in 1973, where the swingarm, equipped with a large upper truss, was hinged to an almost horizontal monoshock absorber anchored far forward to the upper beam of the frame. This scheme allowed a considerable increase in the rear wheel travel, the elimination of stress along most of the frame, and a lighter construction.

Sospensione Monocross della Yamaha YZ250 1980

The further progress of the performance, however, raised the need to adopt kinematics that allowed a progressive and considerable increase in the rigidity of the suspension as the compression increased. In this way, it would have been possible to obtain bikes that behaved well on bumps, but at the same time could stand the hard landings, allowing a progressive transmission of the forces to the frame instead of the hard shocks of the spring bottoming-out. So it was that, at the turn of 1980, all the makers engaged in dirt bikes races were equipped with progressive systems, which soon were also adopted on road bikes. In particular, the systems developed by Japanese manufacturers became quite well known, because they were used as a commercial lever: the Honda Pro-link, the Kawasaki Uni-trak, the Yamaha Monoshock, and the Suzuki Full Floater.

The Richardson-Suzuki Full Floater

The Full Floater is indeed associated with the House of Iwata, but they actually stole the idea – if you wish to venture into reading the court case, here’s the link – of a passionate American biker, Don Richardson, who had designed, manufactured, and adapted it to his own cross bike, and then patented it in 1974, at the age of nineteen.

Suzuki, who had been trying for a while to make such a suspension, had signed with Richardson an option and license agreement in 1978 in order to study his system and apply it to series production in case it proved feasible. The young man then shared all the information he had and also provided several prototypes. In December 1979, Suzuki announced its resignation from the agreement; but, in reality, its technicians and testers were enthusiastic, so much so that the company, in October 1980, took out a Japanese patent for a similar scheme and began selling models with this suspension in 1981.

Richardson sued Suzuki and its subsidiary in the United States and, in March 1987, won the trial, obtaining damage compensation, a royalty of 50 cents on every motorcycle sold in the United States for patent infringement, and 12 dollars on every motorcycle sold in the world, including a guilty verdict for Suzuki’s theft of some non-patentable trade secrets for the practical implementation of the system. Considering that, until the judgment, Suzuki had sold about 1.5 million bikes with Full Floater suspensions, the judgment was in the order of magnitude of around 19 million dollars.

After the inevitable appeal, Richardson got even more, although he did sign an agreement with Suzuki not to reveal the final figure. Perhaps it is not only for technical reasons that the Japanese firm abandoned this system in the late 1980s.

From this article in the Los Angeles Times, published after the ruling, it also emerges that Richardson had already collected money with private agreements from Kawasaki and Yamaha, who had also copied to some extent his patent for their systems of progressive suspension. It therefore seems that a large part of the race for the most efficient suspension in the 1970s and 1980s is due to the genius of a young Californian.

The Full Floater scheme is based on a standard double swingarm, connected by two rods to an upper bell crank hinged to the frame. The monoshock absorber is anchored to the swingarm and the front end of the bell crank. When the swingarm swings up, so does the rear side of the bell crank, therefore the shock absorber is simultaneously compressed on both ends. The lack of any connection between the spring strut and the frame makes this suspension a “full floater”.

Sospensione Full Floater della Suzuki RM125 1981

This scheme makes the suspension progressive and offers the additional advantage that the frame is not directly stressed by the shock absorber, because the forces are transmitted through the bell crank, making the ride more comfortable.

The Kawasaki Uni-Trak

The advantages of the full floater system were obvious, so other manufacturers also ventured into similar systems. The first, already in 1979, had been Kawasaki with the Uni-Trak system. Actually the name indicates a number of different progressive suspension systems. The first of these is however a variation of the Richardson scheme, as it maintains the upper bell crank, connected to the swingarm by a single central rod, while the shock absorber rests not on the swingarm, but on a lower arm parallel to it and anchored to the frame and to the wheel hub. Just looking at it, you understand why Richardson also obtained a financial agreement with this Firm.

Il primo sistema Kawasaki Uni-Trak

The Honda Unit Pro-Link

Honda had followed a slightly different path from the other manufacturers. In fact, its Pro-Link system pursued progressive absorption, but also aimed at reducing the length of the shock absorber to increase the compactness of the system. The original Pro-Link scheme was not a full floater, as the monoshock was connected above the frame. At the bottom, however, it was pivoted to the front part of a triangular element, which in turn was connected to the rear of the swingarm and below, by means of a horizontal connecting rod, to the frame.

Il sistema Honda Pro-Link

Incidentally, this system is used as it is by several other manufacturers, including BMW – on its K1200-1300-1600 series – and Triumph.

The later Unit Pro-Link system was a full floater instead. Developed on Valentino Rossi’s RC211V, this scheme was transferred to series production on the 2003 CBR600RR. In practice, it was a classic Pro-Link, with the only difference being that the shock absorber was anchored to the swingarm and no longer to the frame.

The Full Floater Pro BMW

As we have seen above in the Richardson Full Floater suspension, the shock absorber is in the forward position typical of progressive systems. Instead, in the Full Floater Pro scheme, a single rod connects the swingarm diagonally to the front of the bell crank, which then works the other way round to the traditional scheme. The shock absorber is then connected to the bell crank rear end, so it can be set back by an amount equal to the length of the bell crank itself, far away from the heat of the engine.

Sospensione BMW Full Floater Pro.

Another masterpiece of German mechanics? No way. The Teutonic engineers have simply adopted the functional scheme of the Ducati Soft Damp suspension, used in the ‘80s and ‘90s on many models of the Italian firm’s, from the Paso to the 916-996-998 series. With this solution, Ducati had brilliantly solved the problem of creating a progressive suspension in the narrow space between the rear cylinder exhaust of the long V2 longitudinal engine and the wheel.

Sospensione Soft Damp della Ducati 996

Ultimately, kudos to BMW for having the fantasy to resurrect from history a scheme that has actually solved its technical problem. The “Pro” part of its suspension name, however, can remain in the fluff drawer.

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What Makes the BMW GS so Successful?

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Intro

Basic premise: I am a BMW K models lover. I owned eleven BMW motorcycles: seven of them are K, including the current one; and only one GS, which was sold after a few months because I often preferred to ride my K1200GT. While I’m far from being a GS maniac, I have studied this bike series for a long time and have ridden many miles on all of its versions, from the R1150GS onwards, so I can speak knowledgeably about its strengths and weaknesses.

I continually meet proud GS owners and curious non-owners who bombard me with questions about the BMW GS, clearly the biggest motorcycle phenomenon of the last twenty years, so I was naturally drawn to investigate the reasons for this success.

I speak, of course, of the real GS—the R series 1200 or the 1250 in its standard or Adventure versions. There are other models, from the new F850GS down to the G310GS, but they are very different in layout and they don’t have the charisma of the most desired bike.

The real GS is a top seller, more than any other model, at least in Italy and other European countries, including little teen-ager bikes that cost a fifth, and its success only increases over time.

Those who have it are proud of it and tend to be loyal, but if they betray that loyalty, they often retrace their steps. Those who don’t have it think and talk about it often, sometimes just to criticize it:

  • it costs too much
  • it is ugly
  • the shaft is hard and unbalances the ride
  • with that suspension you cannot feel the front end.

More often, however, they wonder if maintenance is affordable, or if the seat is too high; but, above all, how can those who have it ride so fast. Because the GS is the Total Weapon, it is a magical object that transforms any toad biker into a Prince Charming.

In short, the GS is the bike that everyone must deal with, surrounded by its own special aura. Is this aura based on real facts? Or is it just marketing?

Some History

Long ago, serious motorcyclists were clearly divided into two categories: asphalt lovers and mud lovers; the former used to buy road motorcycles, possibly with a fairing; the latter, single-cylinder dirt bikes.

Things changed with the birth of enduros, a genre invented by Yamaha in the late ’70s with the XT500—bikes suitable for dirt roads and relatively challenging off-road tracks, but practical and comfortable enough to be used for long journeys on asphalt.

While the larger and more expensive touring bikes were not very common in the ‘80s, the more affordable single-cylinder enduros were very successful. During this decade the twin-cylinder BMW R80 G/S appeared, the progenitor of the modern adventure category. It seemed unnecessarily large and heavy then – even if seen today next to the R1250GS Adventure, it looks like its lifeboat – but it won several Paris-Dakar races, creating a solid reputation eating up Saharan tracks. For this and other reasons, it made his way into the hearts of fans.

A lot has happened since then. Initially, BMW was imitated by Honda (with its Africa Twin) and other makers. In recent years, however, adventure motorcycles and crossovers (two largely overlapping categories, the second designed more specifically for road use) have supplanted the super-sport and naked bikes in the hearts of motorcyclists. In this new era, the GS is the undisputed queen.

Today most bikers choose a GS or another adventure bike or a crossover, even if they seldom travel and the only dirt road they will see is the driveway of a bed & breakfast in Tuscany. It’s remarkable that the top seller among the classic, old-fashioned tourers, the BMW R1250RT, sells at the rate of only one for every 14 (fourteen) GS bikes sold.

How can this result be explained?

Reasons for Success

Marketing & Communication

First of all, behind the GS success, there is a hell of a lot of marketing. BMW mainly sells cars and cleverly exploits the ego of their buyers, convincing them that the GS is perfect for the Successful Man, and that it is so safe and easy to drive that anyone can ride it as a first bike.

BMW has also been the first in Europe to utilize balloon loans to allow many people to bring home a motorcycle that they could not otherwise afford.

Another strength is communication. Every single GS advertisement promises the freedom to go anywhere. Many GS buyers use it for commuting and little else, but they buy what really matters—the Dream of Absolute Freedom. This bike explicitly promised to be unstoppable, and even when, years ago, most GS owners were left on foot due to a stupid electronic problem, the message remained fixed in their hearts.

Design

The GS is certainly not the most elegant motorcycle in the world, but it is solid, well made, and has a masculine, robust, professional look with few frills. It looks like a Bosch tool, and it’s no coincidence that its cases resemble those of drills. The GS transmits competence and promises to extend this quality to its riders.

Technique

BMW was the first motorcycle manufacturer to fit its motorcycles with accessories, often of clear automotive derivation, to make them easier, more comfortable, safer, and more appealing. First came the ABS. It was proposed in the BMW K100 way back in 1988 (a fact that boosts my K lover pride), soon became the favorite accessory of the German brand customers and in 2012 it became a standard feature on all its models, way before any other maker.

Then came the traction control, the heated grips, the electro-assisted gearshift also in downshift, the automatic speed control, and dozens of other accessories that can raise the price of a bike by thousands of dollars.

The GS is also a concentration of unconventional technical choices which, as a whole, make the riding experience quite different from any other bike:

  • integral braking system
  • boxer engine
  • shaft drive
  • Paralever rear suspension
  • Telelever front suspension.

Let’s see them in detail.

1)      Integral Braking System

This has been offered standard or optional on the BMW R and K since the early 2000s. With it, the handlebar lever simultaneously activates both brakes, and the pedal can activate only the rear brake. It is therefore impossible to operate the front brake only, which creates a series of interesting advantages:

  • simplifies the braking via a single command that perfectly balances front and rear braking, like on cars;
  • eliminates the self-righting effect typically induced when using the front brake alone while cornering;
  • helps to reduce nosediving while braking[1].

All this without precluding use of just the rear brake, needed in certain maneuvers such as U-turns, hairpin bends, and recovering from running too wide while turning.

2)      Boxer Engine

BMW bikes have always been distinctive from others because of the large twin-cylinder heads protruding from their sides, present only in some Eastern European models born as clones of BMW Wehrmacht sidecars. The production of K models began in the early 1980s, but, even today, many BMW customers still snub them, and consider their inline 3- and 4-cylinder engines essentially a mistake.

Before listing the real strengths of the boxer, let’s start by debunking an imaginary quality: the legendary low center of gravity. In today’s BMW, it simply does not exist.

Years ago, this kind of engine was mounted closer to the ground and actually helped to lower the center of gravity compared to other solutions. The increase in displacement and, therefore, the already considerable width of this architecture, coupled with the greater leaning angles enabled by modern tires, have imposed a much higher mounting, raising the center of gravity to a level comparable to other engine layouts.

Apart from this, the boxer engine offers some interesting advantages.

First, it transmits much less heat because the heads are relatively far from the rider and are perfectly exposed to dynamic ventilation.

Above all, the architecture with opposed cylinders guarantees, among the two-cylinders, the maximum regularity of rotation, particularly at low rpm, a traditional flaw of the twins. Any two-cylinder V-engine under 3000 rpm kicks, while the BMW boxer remains smooth below 2000 rpm in any gear even with full throttle, thus allowing the rider not to worry about the gear engaged: a great advantage, especially for beginners and relaxed riders.

The boxer layout also has some flaws. In addition to the engine width cited above, the torque reaction induced by the longitudinal crankshaft should be mentioned. An increase in rpms pulls the bike to the right side, typically by twisting the throttle at idle. Since 2004, this problem has been greatly reduced on BMWs, inserting a countershaft under the crankshaft; and virtually eliminated since 2013 with the new water-cooled boxer, where different transmission components rotate in the opposite direction of the crankshaft.

Incidentally, as a BMW K lover, I have to point out that the same problem of torque reaction should have affected even the 3- and 4-cylinder in-line engines of the K series, that also have the longitudinal crankshaft, but it was overcome brilliantly from the start by mounting the flywheel on the primary transmission shaft—and all that in 1983.

3)      Shaft Drive

Many touring bikes are equipped with a shaft drive; but, among the adventure motorcycles and crossovers, it is rare. Other than on the GS, it is found only on the Yamaha Super Ténéré and the Honda Crosstourer.

The shaft has the great advantage of eliminating the need to clean and lubricate the chain every 500-1000 km, not a problem for motorcyclists accustomed to this practice, but a considerable hassle for those coming from cars or scooters and, in general, for those who travel long distances.

4)      Paralever Rear Suspension

In the past, shaft drives caused the rear suspension to extend in acceleration and to compress while braking, a behavior that makes the ride awkward. BMW solved this problem by adding a second wishbone to the suspension and a universal joint between the shaft and the final bevel gear where there used to be only one on the gearbox side. Thanks to these devices and well-designed flexible couplings, the shaft transmission behaves practically like a chain – even simulating the chain pull! – the only real difference being the greater silence. Whoever says the opposite surely has never driven a modern shaft-equipped bike.

5)      Telelever Front Suspension

Esistono altre moto con il motore boxer o con la trasmissione ad albero e la sospensione posteriore a quadrilatero, ma nessuna moto diversa da una BMW R o K ha la sospensione anteriore Telelever[2].

Other bikes are equipped with a boxer engine or a shaft drive with double swingarm rear suspension, but no bike other than a BMW R or K features the Telelever front suspension which, as is well-known, drastically reduces nosediving while braking[1]. This effect is not achieved by dumping the front shock absorber and thereby worsening the bump absorption (as happened on some Japanese motorcycles of the past), but by means of a peculiar geometry of the suspension which prevents the shortening of the wheelbase while braking. This fact allows the suspension compression over bumps while minimizing the compression due to weight transfer toward the front wheel.

This makes it possible to use an extremely soft shock absorber, very effective on hard bumps, while avoiding the excessive fork compression that would occur with a standard fork during hard brakings.

The advantages of this feature are considerable:

  • the suspension perfectly absorbs the bumps, transmitting minimal stress to the handlebar;
  • the bike keeps a substantially flat attitude while braking, even squeezing the lever, and this allows:
    • to go into corners while braking quite hard without problems;
    • to use the front brake even in a clumsy way, and even while cornering, without negative repercussions;
    • a very efficient and mentally less demanding drive;
    • unparalleled riding comfort for rider and passenger, and much less prone to jolts and attitude changes even in sporty driving;
    • the avoided reduction of the wheelbase while braking that was mentioned above notably increases the stability of the bike during killer brakings;
  • it is possible to apply the braking force on the front wheel almost instantaneously, rather than wait for the complete compression of the suspension, which results in a drastic reduction in the risk of panic-stop locks (currently avoided by the ABS).

Telelever detractors claim that it would prevent the driver from feeling the front wheel while braking, particularly in sporty driving. Well, after a lifetime of tests and comparisons, I can definitely say that this is nonsense. The proof is that those who drive a GS tend to go faster than with other bikes, which means that the bike gives them better performance and, thus, more confidence. This suspension is simply different; and, like all different things, it requires you to review your beliefs, an exercise that is not easy for some.

I detrattori del Telelever affermano che esso impedirebbe di percepire il comportamento della ruota anteriore, particolarmente nella guida sportiva. Beh, dopo una vita di prove e comparazioni, posso serenamente affermare che questa è una fesseria. Prova ne sia il fatto che chi guida un GS tende ad andare più veloce che con altre moto, il che vuol dire che la moto gli dà più confidenza. Questa sospensione è semplicemente diversa, e come tutte le cose diverse, richiede di rivedere le proprie convinzioni, esercizio non facile per alcuni.

Conclusion

In short, all these features contribute to making the GS a bike that is easy to buy and maintain, comfortable to ride, and easy to drive—so much so that it is really foolproof. Relatively limited driving skills are enough to make it go fast and with a noticeably reduced mental commitment. That’s why those who try it usually fall in love with it.

In short, if you have a GS, the real one, you have made a good purchase.

If you don’t have it, what are you waiting for?


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[1] Actually, In the case of GS this effect is less important than on other bikes, as the Telelever suspension, which will be discussed later, provides right this effect, among other things..

[2] There is a different design with very similar effects: the Hossack quadrilateral suspension (Duolever) that equips the recent BMW K models (1200, 1300, and 1600) and the new Honda Gold Wing.