Categories
Uncategorized

The Evolution of the Dirtbike.

                Although its purpose and general design has remained the same for over 50 years, the dirtbike has evolved considerably. With its evolution, the sport of motocross has changed with it. The dirtbike’s improvements often occur alongside its road-going counterparts. No matter how much dirtbikes change, one thing is for sure; manufacturers will continue to improve their bikes to get that competitive edge.
The 60’s: The Early Days.
                In the early days of motocross, the bikes often resembled something you might find on the street. Knobby tires helped bikes get traction off-road. Fiberglass fenders appeared in the 60s, making the bikes lighter then the steel they replaced. Motocross races of the time had smaller jumps then what is seen today, and they often incorporated natural terrain into the track.
Picture by Peprovira of a 60’s Bultaco dirtbike. Note the low-slung exhaust.
The 70’s: Rise of the Factory Teams.
                Motocross’ incredible popularity meant that a wide range of manufacturers were not only making dirtbikes but also fielding factory-backed pro motocross teams. Manufacturers from all over the world began making motocross bikes bringing with them innovations. Harley Davidson even got in on the act for several years. During this time, bikes saw new materials introduced to bikes such as plastic and aluminum, which meant better performance. During the 70s aluminum gas tanks appeared, as well as aluminum wheels helping the bikes to become lighter. Plastic fenders appeared as well. Factory “works” bikes appeared at professional races, with high-performance modifications not found on production bikes, showing how important the sport was for manufacturers. An example of this was Honda and their Mugen performance division.
Picture by Jeff Sanders of a 70’s Maico.
The 80’s: Changes for Bikes and Tracks.

Few eras saw such radical changes in motocross bikes then the 1980s. One of the significant improvements to come to dirtbikes during this time was the suspension. Bike suspensions got longer travel. The twin rear shocks were replaced by the single mono-shock. Disc brakes appeared as well. Gas tanks became plastic around this time. By looking at motocross’ indoor cousin, Supercross, it becomes clear how much the bikes advanced during this time period. When the first Supercross race was held in the mid 70’s the track closely resembled motocross tracks of that era, consisting of a few jumps. By the 80s, the number of jumps had grown in size and amount. Liquid cooling came about as well during this era.        
                                                                                                       
                As supercross jumps got bigger and bigger bikes evolved as well. One of the big changes came in the form of the inverted or “upside-down” front suspension. Although not universally adopted, the aluminum frame was another significant innovation that was utilized by almost all of the major manufacturers replacing steel ones. Interestingly spoke wheels have remained a constant in motocross for over 50 years, with a few deviations from it. A more recent change is the move to electronic fuel injection. As bikes continue to evolve, manufacturers are always looking for ways to gain an edge on their competitions, but one thing remains the same, great racing.


Picture by KTM AG. A modern KTM dirtbike. Note the heavy use of plastics.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s