Sprocket 13
Small wheels, Big ride
The Sprocket 13 Pit Bike is a concept for a small wheeled adult motorcycle, also known as a mini-moto, or pit bike.

It is designed from scratch to have all the durability and technology of full size motorcycles including shaft driven rear wheel enclosed in a single sided swing arm, hydraulic disc brakes, 75cc pull start engine, magnesium wheels, and other performance parts.

As well as being a concept pit bike, this was also an exercise in 3D modelling using, SolidWorks and Pro-Engineer, and also 3D visualisation, using 3D Studio Max.

Front wheel assembly showing mag-wheels, disc brakes, all terrain tyres, suspension, and integrated mudguard.
Above images shows attachment of rear wheel using a single custom bolt.
Exploded view of swing-arm, shaft drive, and braking assembly, including bearings for pivots and bevel gears of shaft drive.
Drive assembly without swing-arm body illustrating how it works.
Detail view of swing arm pivot bolt, rear shock, engine pull start, and peddle assembly.
View of bolt detail, and fuel cap detail.
View of throttle, handlebar grip, cut-off switch, and brake lever assembly.
Close up of racing exhaust detail.
A foam model was made of the faring and seat using an existing mini-moto, to test the ergonomics of the design. The model above was a very early design.
Initial concept sketches exploring shapes, style, and colour