The girder fork era comprises the veteran, vintage and post-vintage periods.

Veteran - up to 31 December 1918

This is the time when the motorcycle was born, or at least emerged.  Bicycles were the craze from the 1890s into the early 1900s, and the internal combustion engine was in its infancy.  It didn’t take long for enterprising souls to fit small internal combustion engines into what were essentially heavy duty bicycle frames. We can thank the Belgian Werner concern for first placing the motor in the bicycle frame where the pedals once were.  Motor cars were relatively expensive and motorcycles offered more affordable motoring.

The pioneers of the veteran era saw the development of essential components such as the carburettor, the high-tension magneto, and the sparking plug.  This was a time of great enthusiasm, design experimentation, innovation and rapid development.   Within a very short period veteran motorcycles had seen it all; overhead camshafts, multi-valve cylinder heads, multiple cylinders, shaft drive to the rear wheel, clutches, gearboxes, rear suspension.  These innovations were refined over the following decades.

Broadly speaking, the ‘pioneer’ veteran motorcycle (up to around 1910) will have a simple single cylinder side-valve motor comprising a cast iron cylinder and head with the valve springs exposed.  Most riders needn’t concern themselves with changing gears because there weren’t any, just one speed via a leather belt direct from the crankshaft pulley to the back wheel.  The makers may have thoughtfully provided pedals for starting the motor and also enable the rider to offer a little ‘light pedal assistance’ to urge his mount up the steeper hills!  The rider will sit on a leather pan-type saddle mounted towards the rear of the bike, with long handlebars sweeping back towards them.  There will be an array of controls on the handlebars – air, fuel and ignition lever (often mounted on the flat sided petrol tank), an exhaust valve lifter and perhaps a front brake lever operating a bicycle type stirrup brake – useful for removing paint from the wheel rim rather than any effective retardation!  There will be an oil pump plunger usually also on the side of the petrol tank for the rider to periodically ‘charge’ his motor with fresh oil.

Most veteran four stroke motors have side valves or inlet-over-exhaust arrangements. Single cylinder two & four stroke motors are most common.  Notable exceptions were Douglas who made flat twins, and the larger capacity V-twins from makers such as JAP and most American factories.

Later veterans sport such refinements as a clutch and a simple gearbox with 2 or even 3 speeds selected with a hand lever.  British bikes mostly had belt drive, American examples used chains.  Front suspension will be the girder type with rudimentary coil or leaf springs.  If fitted, lights will most likely be the acetylene gas burning type where the flammable gas is generated by dripping water into carbide granules inside a canister.  The bike will have large diameter wheels (eg 26”) fitted with rather skinny (eg 21/2”) beaded edge tyres that require high air pressure to keep them on the rim.  The rear brake is typically a rubber block pressed against the belt rim.  More advanced models may have an external contracting band design.  Fortunately, the bike will be quite lightweight and not terrifyingly fast – about 50-70kph cruising speed.  But there are exceptions to the rule aplenty.  The veteran period is arguably the most fascinating, with a vast array of manufacturers each with their individual designs.  

Riding a veteran is a unique experience in many ways.  There are control settings to learn in order to extract the best performance from the machine.  But, a good veteran machine is a joy to ride, and some would confess it is almost addictive!

Vintage (1919 – 1930)

Although belt drive is very smooth and quiet, by the early 1920s with engine horsepower steadily increasing, most makers stopped using belt drive on all but their most basic machines in preference for the slip-free and more reliable chain.  Countershaft gearboxes and clutches became the norm.  With the development of improved metals and resultant reliability, makers increasingly fitted overhead valve motors to their more sporting mounts. The earlier leather-covered pan saddle gave way to more forgiving mattress spring types, except on many American and European models.

In the late twenties, the shapely saddle tank appeared replacing the former ‘flat-tank’ design.  Compact and fuss-free electric lighting sets replaced acetylene gas equipment. Twist grip throttles were replacing the throttle lever, but gear selection was still by hand.

A significant improvement of the period was the development of reliable mechanical oil pumps necessary to lubricate motors that now revved harder and developed more power. By the end of the decade the manual hand oil pump, oil sight glass and ‘drip-feed’ lubrication was gone.

Motorcycle design had evolved into relatively standard layouts, a far cry from the highly diverse and individual ‘experimentations’ of the early veteran days.  Of course manufacturers continued to refine their designs and introduce various innovations. 

A vintage bike is typically reliable, handles well, is relatively light and has surprisingly satisfying performance.  Some people suggest the motorcycle reached its peak in the ‘20’s, with subsequent improvements only resulting from steady evolution of technology and materials.  Now there’s cause for some discussion!

Post Vintage (1931—1947)

Into the 1930’s bikes got faster, more comfortable ... and heavier due to sturdier frames, stronger gearboxes, generators and batteries for the almost universally fitted electric lighting now required by lawmakers. 

From around the mid-1930s, overhead valve motors became more common, with side valve designs reserved for budget models and sidecar hauling.  Cylinder barrels and cylinder heads were still being cast in iron, some makers using bronze.  Aluminium alloy heads were relatively ‘exotic’ until after WWII and even then were reserved for sporting models.

Most bikes now had four-speed gearboxes with positive-stop foot change pedal. Apart from the handlebar-mounted ignition lever, riders could now keep their hands in position on the hand grips and their feet on the footrests – rather comforting really as a good 500cc post-vintage machine can cruise effortlessly at 80-90kph and take hills in its stride.

One aspect of motorcycle design that was perhaps oddly slow to be developed by many makers is rear suspension.  Before WWII the rigid frame was pretty well standard fare despite various rear suspension innovations being fitted to motorcycles from the veteran days. This is where discussions about handling and effective damping can begin!

And that brings us to the telescopic front fork.  Pioneered by Nimbus in 1934 (one year before BMW) the hydraulically dampened telescopic fork offered simple lines and a supple ride.  The design was widely adopted by the industry from the late 1940’s.  Of the more popular makers, Matchless were quick to develop their ‘Teledraulic’ fork, fitting it to their famous wartime G3L models and giving them an edge over their immediate post-war competitors.   By 1948 the girder fork was gone, with perhaps one exception the 'Girdraulic' design used by Vincent into the mid 1950s.

Note: The above is a very general interpretation intended as a short overview for those less familiar with pre-WWII motorcycles.  The author acknowledges that there are always exceptions!