What advantages does the new material offer and what can't it do? We put eight trekking bikes with fibre frames under the microscope and, for the first time, took stiffness measurements in the laboratory after the test ride.
A simple addition amazed us: the total value of our test field of eight carbon bikes is almost 18,000 euros, so the average for each carbon bike is 2250 euros! This clearly emphasises that carbon frames are a very expensive piece of high-tech.
However, none of our test bike frames are manufactured in Germany or Europe. In China, a well-equipped industry is ready to implement the specifications of European developers in a high-tech production process that is precisely tailored to the design. All frames were developed and designed in-house by the respective supplier. Firstly, high raw material prices make a carbon frame expensive. The small bicycle industry has to compete with the much more financially powerful aeroplane and car industries for limited capacities.
Secondly, the development of a new frame has become a matter for highly specialised engineers. This is because, although there are an infinite number of variables that can ideally be improved with carbon fibre, they can also be done wrong. For this reason, it is now mandatory to develop and virtually test frames on the computer before an order is placed for frame construction.
Thirdly, the technical complexity of the manufacturing process with many possible sources of error leads to a relatively high reject rate for the sake of product safety. Product and riding safety must also be the highest criterion for every carbon bike. For this reason, we measured the stiffness of the head tube for the first time in this test field and tested it in practice through extensive riding tests. This value reflects the riding safety of a frame.
Many years of experience with this measurement at TOUR and BIKE have shown that a frame with a torsional stiffness of around 75 Nm/° or more can be considered stable for rider weights without limits and with average riding ability.
The bikes in the test:
Focus Burrito
Gazelle Lite Line City
Koga Miyata Carbolite
KTM Chronos LC
Maxcycles Carrera
Simplon Nanolight K3
Stevens Strada 1000
Trek X-800
