|ATUJARA MCC - RACING INTO THE FUTURE|
The Tilbrook Motorcycle
Motorcyclists of the 1990s are probably aware that before the advent of Japanese mass
production (which began to make an impact on the worlds motorcycle markets early in the
1960s) the majority of riders were on British machines. Those motorcycles of European
and American origin were not quite so popular, possibly because of expense and tariff
It would not be surprising if few of todays enthusiasts know that several Australian motorcycle manufacturers existed during the years prior to the 1939-1945 war, using mostly imported engines, frame lugs, gearboxes, wheels, and metalwork. What is not generally known is that South Australia had its own motorcycle manufacturer from 1949 until 1956 producing the Tilbrook 197 and 125 tourers and 125c.c. racers.
The driving force behind the venture was Rex Paterson Tilbrook who had already achieved widespread acknowledgment for his large range of motorcycle accessories and the popular lightweight Tilbrook sidecar series with a greater selection of models than any other Australian manufacturer. The difference between the Tilbrook and other previous Australian machines was that apart from the Villiers engine/gearbox unit and the Lucas lighting set, the rest was made in South Australia, and whereas earlier Australian models looked similar to imported machines with the main difference being generally only the name on the petrol tank, the Tilbrook had a unique appearance using a combination of features considered by Rex to be best suited for Australian conditions.
The Tilbrook was radically different, with a massive four gallon, (eighteen litre) petrol tank expressly for long range Australian touring, a large flared front mudguard and combined rear mudguard stressed seat assembly. This was years before Triumph launched their bathtub model to protect the rider from the mud and dust of unsealed roads which were much more prevalent in the 1950s than they are today.
In an era when few motorcycles had rear suspension and most lightweights had limited travel telescopic forks of the most basic design, Rex produced a swinging arm with underhung springs to reduce the center of gravity for the rear and a radial arm front to provide a machine which handled better than any comparable imported model.
Another feature which was vastly superior to contemporary imported machines were the full width finned aluminum wheel hubs with 37m.m. wide shoes working against shrunk in cast iron linings. The coefficient of friction of this combination was much greater than the normal practice of having the shoe lining working against a pressed steel drum and the greater heat generated under fierce braking was quickly and efficiently dissipated by the air cooled finned drums. Even under intense racing conditions there was never any hint of the brake fade that was so common with steel drums.
All models had steering dampers, generally an optional extra on larger machines and virtually unavailable on smaller models, and all had chrome plated tank racks to protect the paint if the rider wished to carry a parcel or bag on the tank. It is worth remembering that motorcyclists of earlier years used their machines mostly to get to work and back, and many had to carry their work tools of trade as well as their lunch, so a kitbag on the tank was a common method of solving the problem.
Whereas alternative lightweights had d shaped speedometers, the Tilbrook was fitted with an 80m.p.h. instrument having an odometer and trip meter mounted above the headlamp in an easy to read position. Under the press stud fixed seat pad was a capacious compartment to house the battery, tool roll and puncture repair kit, as well as any spares the owner may have thought were necessary. The tool roll consisted of sufficient spanners to completely dismantle and reassemble the machine and included special tools made by the factory for the wheel nuts, swinging arm pivots, spark plug, exhaust pipe flange and head stem ball race lock ring. A tyre pump was provided and this fitted on spigots under the seat/mudguard assembly.
In an era when black was the predominant color, offset by a different color petrol tank for most motorcycles, the Tilbrook had a striking red lacquer all over with nuts and bolts and detachable brackets being cadmium plated and handle bars, tank rack, exhaust system, wheel rims, headlight brackets and levers were chromium plated. A broad white line with a thin black one adjacent on the tank and seat/mudguard assembly completed the cosmetic appearance.
Few British manufacturers (with perhaps B.S.A. being an exception), made many of their components but relied on specialist suppliers for much of their production run. By contrast the Tilbrook factory made the majority of the machine under the one roof including all machining, welding, nut and bolt making, wheel building, exhaust pipe bending silencers handle bars, control levers, plating and painting. Aluminum castings were supplied by a small foundry near the factory and footrest rubbers and seat inserts moulded by S.A. Rubber Mills (now Bridgestone) using dies made at the Tilbrook factory. All toolmaking was carried out at the factory and many of the machines used to produce the components were designed and built on the premises, including an arc welder and an acetylene generator.
Although planning was for volume production, many components were mass produced with tooling made to achieve this, motor cycle popularity declined. The sad fact was that the motor cycle was being phased out as a popular means of transport in favour of second hand motor cars which were becoming more plentiful and cheaper.
Tilbrook produced one last revolutionary model in prototype form which was displayed at the Royal Adelaide Show in 1956. It was never started until it was sold to well known S.A. enthusiast Ralph Datlen about twenty years later, after laying in a corner with some parts stripped for other projects.
The Tilbrook factory continued to make sidecars and accessories for a diminishing market but concentrated on contract work for the supply of tables and chairs, special manufacturing machines and general engineering until it ceased trading and closed down in 1976. It is ironic that Tilbrook products are now sought after equally as fervently as British machines when only a short time ago it was difficult to find a buyer and many ended their life as scrap metal. Those who now own Tilbrook motor cycles are generally those with a flair for perfection and as Rex commented to one restorer, the bikes now look better than when they first left the factory all those years ago.
Tilbrook racing machines had their share of success but their development over a twelve year period is another story.
Alan Wallis O.A.M. Life Member Atujara M.C.C.
Last modified Sunday 4th January 1998