Comfort, performance, control and safety.

The ability of the wheels of a modern automobile to move significantly up and down while the vehicle's chassis (and occupants) moves only a little, is based on the vehicle's capacity to insulate the wheels from the body with a suspension system. Vehicles with suspension systems invariably provide a vastly more comfortable and safer ride over rough terrain than those without.

A text on cycling technology has this to say about bicycle suspensions:

"Shock-absorbing mechanisms may add weight, but can greatly increase comfort, performance and control. Anyone who has experienced the hammering of a rough track or pot holed road will appreciate the benefit of a smoother ride; what is surprising is that shock absorption also gives better handling and greater speed; in fact descents are 20 per cent faster on average. Suspension also gives enhanced traction, and this results in much quicker cornering as well as better climbing." (emphasis mine)

We don't have too many hills in harness racing, but we sure have plenty of rough tracks and corners and we can always use improved traction, that is, less skidding on bends.

There have been many who would like to have had sulkies with a light, efficient and affordable suspension system, but, prior to 1996, such sulkies have seldom existed, and, where they did exist, have not been generally available. The only known independent suspension system for sulkies made in the southern hemisphere prior to 1967 was inventor Les Brown's ingenious prototype, illustrated in the drawing below - which drawing is based on the only surviving (in 1999) piece of the Brown sulky, an old and very rusty undercarriage:

Fig. 1

In the above drawing, only the undercarriage is drawn strictly to scale. Les's undercarriage relied for damping on the friction between the greased vertical sliding components and their outer casing. Each wheel axle was attached to the two forks. The forks' vertical movement was controlled by two coil springs which limited upward movement, while the cups and cross pieces shown above the undercarriage cross member limited downward movement. The total available vertical movement was a little less than 25mm (or one inch).

The next attempt at independent suspension was by Jim Walsh a year after he joined his father in the sulky building industry in 1967. Illustrated below is a close-up of the suspension system on the nearside wheel of the Walsh prototype:

Fig. 2 Detail of Jim Walsh's first independent sulky suspension in 1968. With about double the suspension movement of Les Brown's model, plus effective dampers, this sulky was used by Film Australia as a stable camera mount for the filming of the award-winning 1976 short, 'PACE'. During the making of that film the sulky was wrecked when the horse pulling it jumped a shadow and fell.

In the mid 1980s, R.J. Walsh & Son produced three light gigs with rubber-in-shear independent suspension systems. These were primarily for training and pleasure driving.

Fig. 3 The first "gig" the company ever made, circa 1985. It worked well enough, but was too heavy for a work cart and too light for a gig

Walsh's third attempt at a light suspension system, the 'Floating Link Suspension' (FLS) is a stunningly simple and elegant sulky suspension system, which not only overcomes the myriad problems which have hitherto defeated would-be inventors of sulky suspensions, but also some of the intractable problems associated with conventional undercarts and wheels.

Fig. 4 A Regal offset sulky fitted with the new Floating Link Suspension (Fairfield Paceway, 1997)

Fig. 5 This shot shows multi Inter Dominion winner, Brian Hancock, observing the suspension working on his private training track at Albion Park, near Wollongong, NSW. This was an early prototype of the Regal Brumby light training sulky. It was later purchased by stuntman Vince Silvestro and fitted with a large rear-mounted fireworks tray and heavier springs. It was first used at Harold Park on Friday, November 14, 1997. The sulky is, according to Vince, "The greatest training bike ever invented anywhere."

Fig. 6 This image illustrates the extreme simplicity of the design, the complex trusses of a conventional light weight undercarriage conspicuous by their absence. Gone too are the two vertical outer undercarriage legs of conventional sulkies which form a "V" with the outside wheel forks, and are one of the main causes of wheel locking in close racing.

Fig. 7 Vince 'Hot to Trot' Silvestro and the first public appearance of his new stunt sulky with Floating Link Suspension at Young, NSW, in November 1997.

Not so obvious however, are the two linked axles which are the major distinguishing characteristic of the design. These enable the nearside wheel, for example, to be displaced vertically without affecting the camber of the offside wheel.

The wheels are standard 26" x 2" x 1-3/4" radial-spoked jog wheels. They run on stub axles which do not permit the excessive bearing loads typical of pull-through axles, and therefore turn more freely. They are also very much easier to remove and replace than on conventional sulkies.

An additional advantage of this suspension system is that the wheels are subjected to very much lower stresses than they would be supporting the same load, but rigidly mounted as in a conventional sulky. Thus spokes, rims, bearings and tyres all last longer on a sulky with FLS suspension.

To remove a wheel, the retaining screw and washers are removed, the outer stay swung clear, and the wheel merely slid off its axle. Reverse the procedure to replace.

Also not apparent from the photos is the fact that the springs are quickly and easily adjustable for different driver weights between 60 and 120 kgs, with heavier springs available for drivers outside that range. Similarly, the dampers have four easily-changed damping rates to compensate for wear over the life of the damper.

The new suspension offers not just a speed advantage (so far unquantified), but significantly improved comfort and safety advantages over conventional vehicles.

To remove a wheel, the retaining screw and washers are removed, the outer stay swung clear, and the wheel merely slid off its axle. Reverse the procedure to replace. Also not apparent from the photos is the fact that the springs are quickly and easily adjustable for different driver weights between 60 and 120 kgs, with heavier springs available for drivers outside that range. Similarly, the dampers have four easily-changed damping rates to compensate for wear over the life of the damper. The new suspension offers not just a speed advantage (so far unquantified), but significantly improved comfort and safety advantages over conventional vehicles. Consider, for example, a situation where a conventional sulky's wheel passes over the body of a fallen driver on the track. Rigidly attached to the sulky frame and supporting the weight of the driver, the wheel hits the obstruction hard. That impact is multiplied by vertical acceleration as the wheel rises over the obstacle and thrusts the sulky into the air. When the sulky comes down, the rigid mounting of the wheels to the frame ensures that wheel and frame failure is highly likely.

By contrast, the wheel of a sulky fitted with a FLS system will be displaced vertically much more rapidly than the frame it supports. This transfers less energy to the sulky proper, and reduces the impact of the wheel on the fallen driver. Equally, it ensures that the vertical acceleration of the whole sulky is reduced, lowering the maximum height reached and reducing the impact when the sulky returns to the track. It also increases the probability that the driver will be able to retain his/her seat, and with it control of the sulky and horse throughout the incident. Furthermore, in the event that the driver manages to stay in the sulky, the impact when the sulky hits the ground is a fraction of that experienced in an ordinary sulky, dramatically reducing the probability of injury to the driver.

There are very significant occupational health and welfare advantages to be gained by use of sulkies fitted with FLS systems. For a fuller examination of such issues by a sports injury specialist, see Health & Welfare Benefits of the Brumby.

After early testing validated effectiveness and practicality of the new suspension, a racing version was put before the race sulky approval process of the Australian Harness Racing Council in 1997, where it remains under consideration as at November 25, 2000.

Meanwhile, anecdotal evidence from some northern hemisphere countries indicates that only suspension sulkies may be approved for the training role in future.

In November, 2000, French harness racing enthusiast, Claude Lamaison, tested a Regal suspension sulky on the track in Temora, New South Wales. After returning home she posted a public e-mail on the Ausharness list which included the following: "Your suspended sulkies are nothing less than PURE MARVELS and I know personally about the comfort they provide. It's great!"

However, right now this revolutionary suspension system is now available throughout the world in the Regal Brumby Training sulky.