TOUR: 30 years ago, TOUR started testing road bikes reproducibly on test benches, initially for bottom bracket and headset stiffness. What was the motivation for this and how did it come about?
Dirk Zedler: The first carbon wave began in the mid to late 1980s and at the same time, welded aluminium frames from the USA reached Europe. While carbon was initially almost phased out again due to quality problems, aluminium frames from Klein and Cannondale and later from Müsing from Germany and Principia from Denmark were serious challengers to the somewhat dusty Italian steel frame manufacturers. Their reaction to the light alloy frames were increasingly thin-walled tubes, which posed an increasing challenge, shall we say, when riding downhill. As young engineers, Robert and I could now either write against the ego of the classics or provide evidence of technical properties. So we sat down and drew our first test sketches on napkins in the organic farm pub.
TOUR: How was this received by readers and the racing bike industry?
Dirk Zedler: German readers are very tech-savvy and liked this right from the start. We then relatively quickly created market overviews at TOUR that not only contained prices, colours, sizes and weights, but also decision criteria based on measured values. The bike and frame manufacturers in Central Europe and the USA were enthusiastic, but the southerners were not. For TOUR, a two-tier society developed: the manufacturers who rose to the challenge and wanted to be at the forefront, and the manufacturers who favoured the preservation of vested interests and no longer sent bikes to the tests. Today, 30 years later, the former opponents also work with the descendants of the original TOUR tests.
TOUR: How have road bikes developed since the introduction of the TOUR tests?
Dirk Zedler: The TOUR tests, in which riding characteristics are expressed in figures, made oversizing socially acceptable, i.e. larger-volume and thinner-walled frame tubes. Manufacturers began a veritable race to maximise stiffness while minimising weight. The stiffness-to-weight factor based on the steering head test rig became an international advertising tool. This was sometimes taken to extremes and advertising campaigns were launched because a frame was one point better than the competition. Readers didn't really care about this, but they did care that the frames were becoming increasingly uncomfortable. We countered this from around the mid-2000s by testing the comfort of the fork and rear triangle. Today, it is possible to build lightweight, stable and yet comfortable framesets using carbon - squaring the circle, which is virtually impossible with metallic materials.
TOUR: Are racing bikes safe vehicles to ride on the road in 2025?
Dirk Zedler: Today, nobody disputes that the pioneering work and perseverance of TOUR and later BIKE has made the bicycle significantly better and safer to ride. But that was not the only improvement that TOUR initiated. With numerous articles, we pointed out the deficits of bicycles in terms of durability, ergo safety. Key design features of today's racing bikes can be traced back to my findings in the preparation of expert reports, which we brought to the industry with TOUR. Many years before the standards, TOUR sensitised manufacturers to the issues of durability and safety. The safety of today's racing bikes is much higher than 10, 20 or even 30 years ago.
TOUR: Nowadays, modern racing bikes are almost exclusively built on carbon frames. Is this also the best material from a technical point of view? How durable are carbon frames? Are there still risks?
Dirk Zedler: Carbon is the frame material of choice for sporty bikes - with no ifs or buts. No other material can even come close to realising the desired properties at the same level. Carbon has also made incredible progress in terms of operational stability, but increasingly also overload and impact behaviour. The greatest dangers are posed by the user when, for example, the clamp of the wheel carrier is placed on the top tube and tightened without feeling.
TOUR: How should the trend towards system integration be assessed from a technical perspective?
Dirk Zedler: Technically, system integration offers great opportunities for a tidy and therefore aerodynamic bike. The disadvantage is the significant increase in maintenance and repair costs. Some designs with internally routed cables can drive a mechanic crazy. Maintenance becomes more time-consuming and expensive. Another disadvantage is that repairs are only possible with original parts, and not every manufacturer stocks sufficient quantities of these.
TOUR: What are the most common technical problems on road bikes from an expert's point of view?
Dirk Zedler: Compared to the past, there is much less to worry about. Designs and testing have improved significantly, but mechanics and users have also gained a better understanding of the material. Carbon steerer tubes are still critical. We have had to deal with a number of recalls in this area and one manufacturer is currently recalling them. The second point is very light saddles and seat posts. Even among lightweight riders, carbon saddle racks, for example, break when they come into contact with a less suitable seat post. You are therefore well advised not to go too far with your own conversions.
Thomas Musch
Publisher
