A road bike must be lightweight and aerodynamic. If the frame is also reasonably comfortable and stable enough to keep the carriage stubbornly on track even at a speed of 70 km/h, then you are dealing with a top of the line road bike, probably all road racers would agree on that. But when is a road bike the best of its class? The answer to this question depends not least on what criteria a road racing bike is judged by in the first place.
When TOUR started systematically recording and evaluating road bikes a bit more than 25 years ago, no one thought that it would one day be a matter of course to measure the aerodynamics of competition road racers in a wind tunnel. Nor was any particular attention paid to comfort initially, the measurable differences being hardly worth mentioning at that time.
The foundation for what became later the first and to this day the most comprehensive objective test procedure for road racing bikes was laid by the unforgotten Hans-Christian Smolik in the 1980s. As a columnist for the TOUR magazine and author of numerous specialist books on bicycle technology, he carried out basic research at the time which continues to have an impact today. In 1987, he developed among other things a method which made it possible to measure not only the vertical compliance, but also the lateral torsion of a frame, as a measure of directional stability and the bike’s tendency to wobble. However, the conclusions to be drawn from the measured values were largely left up to the readers.
THE FOUNDATION OF THE TEST HISTORY
This changed seven years later. In TOUR 11/1994 the two engineers and technical editors Robert Kuehnen and Dirk Zedler presented a test stand measuring the distortion of the frame’s front triangle towards the rear triangle. Not foreseeable at the time: This test stand made TOUR engineering history. Even today, many road bike manufacturers measure the riding stability of their frames with exactly this measuring method. For the TOUR special issue “Bike workshop 4 – frames” published in 1995, 49 framesets made of steel, aluminium, titanium and carbon were tested on the test stand for a large-scale comparative test. The test criteria not only include weight and stiffness in headtube and bottom bracket, but also the mechanical paint and the processing quality. Each of these characteristics are rated with marks ranging from “very good” to “not sufficient”.
The sole winner is the Quantum pro aluminium frame from the US manufacturer Klein, which was named "champion of all classes" by the testers and leads the rankings for weight and headtube stiffness. Well after the turn of the millennium, and basically to this day, the Quantum pro is still considered the benchmark for what is technically feasible with aluminium in frame construction. In the same test the Trek OCLV 5500 as best carbon frame ranks third in the weight ranking after all. The frames of the first OCLV generation were not very stiff at that time, but one could already make out the potential the material carbon was yet to offer in frame constructions.
Author: Manuel Jekel
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