The motorcycle as we know it is always in a state of progression. The manufacturers update their premium sport bikes typically every three to four years when the global economy is poor, but as often as every other year in a strong sales economy. The top sport bike is quite often one of the most expensive bikes in the line-up, and it is used to showcase the latest technology that the manufacturer is capable of bringing to the mass production table. Sometimes the improvements are so impressive that it renders the previous generation obsolete in the eye of the current owner, so much so, that they must purchase the new model. Competition is fierce as the motorcycle manufacturers try to sway owners of other brands towards their camp to increase market share as well as cement the loyalty of their existing customers. The technological improvements each year are staggering and exciting to watch as the manufacturers leap frog each other depending on who is in a new model year, and who is between years. It was in this heat of evolution that I paused and took a look back to see just how far motorcycles have come over the years. If you get the opportunity, open up a history book and have a look at some photos of Motorcycles that existed at the turn of the century, no not the one 12 years ago, the one before that! You may be amazed at both how much, and also how little motorcycles have changed in the last one hundred years.
If we review the first motorcycles born of bicycles sprouting engines and then became the basis of the motorcycles that we know today, we see a startling number of similarities. They had two wheels, one in front and one in back, and no, this is not a given as the last decade has given us the Segway scooter, which is a bi-cycle with its wheels beside each other and a clever propulsion system to challenge our preconceptions of what a two wheeled vehicle can be. The conventional historical motorcycle had its front wheel bolted to a turning mechanism with a rudimentary axle. The turning mechanism came up through the main frame of the chassis, supported by bearings, to the handlebars that allowed you to turn the front wheel to the left and the right. Sound familiar? Over the years, several front suspension systems were tried, from an Indian designed Trailing axle link design, to the English designed Girder Fork that won the Isle of Man on a Norton in 1907. A Castle design followed utilizing a leading axle link system that still exists on custom built ‘springers‘ to this day. As seal design improved, the sliding telescopic fork gained acceptance and appeared again for good it seems in 1937, with the basic design parameters of the fork that dominates and excels today some 75 years later. Behind the front suspension and wheel, was a main frame that held the engine, fuel tank and the seat for the rider behind the tank. This inverted triangle of fuel tank, rider and engine has changed its shape slightly, but has remained largely unaltered for 100 years. Over the years, the engine moved closer to the front tire to maintain front wheel traction as horsepower skyrocketed in the 1930‘s and 40‘s, and more recently the fuel tank changed shape to permit the rider to move forward as well. Grand Prix bikes as recent as the 1974 MV Agusta 500-4 used rudimentary twin shocks out back, mounted perfectly vertical, and still had the rider sitting well over the back wheel as the understanding of factors that effect rear wheel grip were still in their infancy compared to what we know today. Drive chains slowly replaced belts around 1910 to transfer the power from the solid mounted engine and transmission out to the rear wheel which was constantly in motion, this permitted rear suspension freedom without the mandatory belt tension problems. Friction clutches and transmissions showed up and won at the Isle of Man in 1911. That initial system of a separate transmission mounted behind the engine driven by a primary chain or drive belt, survives today in most Harley Davidson’s that sport the tell tale huge left side cover that protects the primary drive system from the elements.
Wheel diameters by and large have stayed about the same size, varying only by a few inches as tire quality improved in leaps and bounds over the course of the year. Tensioned spoked rims, ball bearings, roller chains and pneumatic tires first appeared all together as early as 1885 and were dubbed the “Rover Safety Bicycle”, since that time the improvement in tire technology could warrant a book of itself. Tires had to improve, sometimes leaping ahead of the challenges of speed and heat while trying to hold grip, but most often progress was being pushed from behind by these ever increasing demands. Spokes survived as the preferred method of joining the tires to the axles, but due to the difficulty in sealing hundreds of small spoke holes, inner tubes remained mandatory. The inner tube adds to the heat problem facing road going competition tires, so the solution was found in the solid mag wheel which won its first world championship on the Dunlop shod MV Agusta 500-4 in 1974, ironically the last year this dominant Marquee won a world championship. Yet spokes survive now on every off road motorcycle on the market as heat generation is not a concern.
Perhaps the most important feature of any motorcycle past or present is the device that resides between the rim and the axle, that we call the brakes. We can imagine that brakes probably became mandatory after the very first successful trip involving forward motion. I can imagine that a ditch, tree or fence line must take credit as the very first braking system, but this system was both inconvenient and dangerous. Perimeter rim brakes as we see today on bicycles, are troublesome to mount with suspension, so the better place to mount them was inside the rim. Drum brakes evolved, getting larger and larger as speeds rose, but became impractical to keep cool as they ran in a sealed enclosure. Disc brakes appeared at the GP level around 1973 and survive to this day as the best method of safely stopping our current motorcycles. As we ponder past development, we can see that the ‘geography’ of the motorcycle hasn’t changed much in the last 130 years, but constant refinement of each and every subsystem involved, has dramatically improved the comfort, safety and performance of this vehicle that we love so much!