Stringbike String Driven Bicycle 21 Inch Frame
Stringbike String Driven Bicycle – It’s not just a bike, it’s a piece of art.
- Revolutionary string drive increases efficiency.
- 19 speeds can be shifted while pedaling or while stationary.
- No chain means less mess and quieter rides.
- Magura hydraulic brakes provide consistent braking power.
- Springs in rear hub assist riders pedaling.
Inspiration – A clean, quiet and graceful vehicle that’s what we wanted to create
We started with a clean sheet and challenged conventional bicycle technology. The result is the Stringbike, a revolutionary bicycle drive, using hi-tech materials, technology and high-performance parts from various industries.
Dual Drive – Symmetrical and balanced transmission and rear wheel
On both sides of the rear wheel, a direct power connection transmits the (human) power to the wheel. As a result of this duality, the drive system operates under reduced strain. Gear changing is much easier, as one side has either no or lower load. The Stringbike drive system also allows the spokes to be symmetrical, giving optimum wheel and overall balance.
Pumping-Pulling “Loco-Motion” – No circular motion in the power transmission between the central and rear hubs
The pushing power of the leg is transferred to a pulling motion by the Stringbike swinging arms. The two pairs of double strings make a pumping, alternate motion transferring the power back to the wheels, where the rear hub converts back to circular movement. The motion of the driving system is similar to the natural motion of the human legs, and in some aspects to the motion of the Locomotive.
Driving Geometry – Slightly easier ride, as there is no true deadlock point
Due to Stringdrive’s elliptic driving path, in low gears (typically uphill) the pedals give a “kick-up” resulting in a slightly easier ride, as there is no true deadlock point. However, when the gears are shifted higher, the riding experience will be similar to that of conventional bicycles.
Efficiency – Pure rolling motion with the smallest possible friction loss
A strong drive is highly efficient, as the power transmission between the pedals and the rear wheel is a pure rolling motion with the smallest possible friction loss. However, when it comes to the Stringbike, The ‘string’ is made of a high-density polyethylene cord (HDPE). The efficiency is not affected by the actual position of the gears, thereby retaining its’ high value in all gear positions.
Technology and Materials – High-tech parts and advanced technologies applied in Stringbike
Plasma-nitrate for the glass hard surface to avoid rust.
Laser cut swinging arm from stainless spring steel.
Aluminium-oxide ceramic coating on the pulley.
HDPE (high-density polyethylene) string.
Rear drum able to withstand high-frequency movement and heavy duty springs.
Rear hub parts made by CNC technology.
GMN made ball bearing freewheel instead of ratcheting freewheel mechanism.
Specially shaped spring provides spring loading to each axle. This spring system is used for high-frequency and precise indexing movements.
Gears – 19 gears with non-overlapping transmission ratios on the Stringbike
In each swinging period, the forward movement of the swinging arm pulls the rope forward by means of the rope wheels. The distance between the center of rotation and the shaft changes as the shaft is traveling up and down along this traction path. The traction path has 19 neighboring recesses, and each of them corresponds to a respective gear position.
Weight – Superior function/weight ratio compared to internal speed hubs or lightweight gear systems
The driving system itself has approximately the same weight as the chain transmission, the main difference is that Stringdrive is attached to the frame and needs less maintenance. The strong drive has a superior weight if compared to internal speed hub or lightweight gear systems, based on a gear ratio and function/weight ratio.
Low maintenance high Reliability – Requires much less care compared to conventional chains and gears
Compared to the maintenance requirements of conventional chains and gears, the Stringdrive requires much less care and attention and can be stored through long periods and then used again.