The basis for the assessments and grades of the TOUR road bike tests are standardised and reproducible test procedures that we have developed in collaboration with external experts and have been consistently improving for more than twenty years. To this day, the TOUR test procedure for road bikes sets standards; there is no better method for objectively and comparatively evaluating framesets and components of road bikes and gravel bikes. Here is an overview of our methods, evaluations and test systems.
TOUR road bike test: Classification of the bikes tested
The focus of the TOUR road bike tests is on the complete bike, which is increasingly being designed as a complete vehicle with integrated solutions such as aerodynamically optimised cockpits, integrated brakes and specially tuned wheels. A greater distinction is made according to the intended use of the road bike: the classes of competition road bikes, marathon road bikes, time trial bikes, cyclocross bikes and gravel bikes are each rated differently. For Competition racing bikes aerodynamics and weight of the complete road bike are given particularly high priority, as these two points have a direct impact on riding performance. With Marathon road bikes comfort values or ease of maintenance/adjustment are more important, while aerodynamics play no role.
The TOUR test score is made up of individual assessments in various disciplines, which we weight sensibly. However, not every criterion is equally important for all riders. You can find our weightings of the individual scores in the TOUR road bike test in the following table.
Weighting of the individual scores for competition and marathon road bikes (in per cent)
TOUR road bike test: Geometry test station
On the TOUR geometry test stand, all relevant frame dimensions are determined using a standardised measuring method, independent of manufacturer specifications. This allows different frames and geometries to be compared with each other. The frameset is fixed in the holding device. A series of defined measuring points on the frame and fork are then approached with a laser pointer. From the horizontal and vertical coordinates, TOUR calculates the dimensions and angles that appear in the geometry display and form the basis for the stack to reach (STR).
Weight in TOUR road bike tests
The complete bike weight measured in the TOUR laboratory in the standardised test bike size counts for the evaluation. However, the frame and fork weights are also shown for orientation purposes, as are the wheel weights. The grading scale is designed in such a way that the physical effect of weight and aerodynamics on the average speed is comparable for an average route profile of 1,000 metres in altitude per 100 kilometres. For orientation: the aerodynamic optimisation of the bike can compensate for up to almost four kilograms of weight on such a route.
Simultaneous top marks for weight and aerodynamics are mutually exclusive, but there are bikes that find a very good compromise. If the route is more hilly than our reference route, the importance of weight increases; if the route is flatter, the weight becomes more important. Aerodynamics more important.
Aerodynamics in the TOUR road bike test
How good or bad the aerodynamics of a racing bike are is determined for competition bikes and dynamically in the GST wind tunnel in Immenstaad is measured. The wheels are driven and the TOUR dummy with moving legs simulates the influence of the rider. The weighted measurement over a large flow angle range produces an aerodynamics score, which is included in the overall score for competition bikes at 20 per cent. All information and background information on our wind tunnel tests of complete wheels.
Driving stability
Modern road bike frames are generally very stable. The starting point of the first TOUR test twenty years ago, however, was the fact that racing bike frames of that design suddenly developed an unwanted life of their own at medium and high speeds, which was difficult or impossible for the rider to control. Sometimes a gust of wind or a slight imbalance in the wheel was enough to cause the bike to vibrate.
The best remedy for this is a frame with high steering head stiffness. The higher it is, the greater the riding stability and steering precision. To determine the steering head stiffness, the frame is turned 90 degrees on its side and clamped realistically in the test rig. A dummy is installed in place of the fork and a defined bending and torsion is applied. A dial gauge indicates the deflection. TOUR then calculates the steering head stiffness in Newton metres per degree (Nm/°) from the torsional moment applied and the deflection. Since the aim is not to have an infinitely stiff frame, but one that is sufficiently stable to ride, the stiffness values are capped.
Lateral stiffness and comfort of the road bike fork
The riding safety, steering precision and comfort of a road bike depend not only on the frame, but also to a large extent on the properties of the fork. The less the fork is deformed by lateral forces, the more safely the bike can be steered through bends. The more the fork deflects in the direction of travel, the lower the impact load on the hands. The fork test stand makes it possible to measure the deflection movement of the fork in two load directions. The fork is clamped in the test stand in the same way as on a racing bike. The lateral stiffness is measured successively in the direction of travel (comfort) and laterally. The quotient of test force and deflection in millimetres gives the fork stiffness in newtons per millimetre (N/mm).
Power transmission
Nothing bothers road cyclists more than investing their calf power in deforming the frame instead of in propulsion. This is why the highest possible bottom bracket stiffness is required, and a test system has been developed to measure this, which simulates the worst-case scenario of pedalling. For the measurement, the frameset is realistically fixed to the inclined test stand using a quick release and fitted with a dummy crank. Thanks to a realistic rear wheel contact point with typical degrees of freedom, the frame load and the evasive movement on the test stand and on the road are almost identical. The rear wheel can turn out of line under the pull of the chain, and the inclination of the frame (pedalling out of the saddle) imposes lateral forces on the frame that place a heavy load on it. The extent to which the pedal deflects vertically and transversely to the direction of travel under the influence of the test force is measured. The bottom bracket stiffness in newtons per millimetre (N/mm) is calculated from the test force and the resulting distance.
TOUR comfort measurement of road bike frames
At first glance, you might ask yourself: What is there to move vertically on a diamond frame? However, thanks to modern materials such as carbon and new design concepts such as sloping frames with extended seat posts, seat posts designed as suspension elements or even mechanical suspension concepts, there are now considerable differences between different road bike frames in terms of comfort. The comfort test bench can be used to measure and assess frame comfort. The frameset is clamped vertically at the dropouts. The frame and fork can perform realistic deflection and compression movements.
The suspension travel is measured with the seat post supplied by the manufacturer or, if none is available, with a standard seat post (Ritchey WCS Alu), which is set at the standard frame height of 57 centimetres to a uniform seat height of 750 millimetres between the centre of the bottom bracket and the centre of the saddle frame. The test force is applied vertically behind the intersection of the seat tube and saddle frame. The suspension travel is measured parallel to this at the same distance. Dividing the test force by the travel gives the spring rate of the frame.
Paint test in the TOUR test lab
What good is the best paint if it doesn't last? The TOUR paint test simulates stone chipping and allows a statement to be made about the durability of the protective top coat. The mechanical resistance of the paint is tested in several places. This takes into account the fact that frame sections are painted differently and that frames can be made of several different materials. During the paint test, a chisel simulates stone chipping or chain impact. Starting at a height of ten centimetres, the height is increased by ten centimetres until the paint gives way or the maximum drop height of 50 centimetres is reached.
Equipment: How gears, brakes and tyres are rated in TOUR road bike tests
We give extra marks for gears, brakes and tyres in our road bike testsas they have a significant influence on the function of the bike. The ratings are based on component tests that we regularly carry out for these components, as well as their interaction on the respective test bike.
Maintenance and adjustment
The test assesses how easy a bike is to maintain and adjust. Marks are deducted, for example, for special tools required, particularly complex detailed solutions or maintenance work that can only be carried out in specialised workshops.
Testing technology
The planning and design of the test stands and laboratory equipment were developed almost exclusively in close co-operation with Zedler-Institut für Fahrradtechnik und -Sicherheit GmbH. Managing Director Dirk Zedler is a graduate engineer for vehicle technology and a publicly appointed and sworn bicycle expert. The active racing cyclist and five-time Transalp finisher has been working for TOUR since the beginning of 1994. In addition to the "Workshop" section, he has written many ground-breaking articles on road bike technology and safety. You can find more information here: www.zedler.de
The modern bicycle testing technology used by TOUR is recognised as having set standards over the past 20 years and changed the road bike for the better. Terms such as the Stiffness-to-Weight-Factor (STW) have become a global communication tool for the entire bicycle industry thanks to the work of TOUR. Manufacturers who want to optimise their frames and components before launching them on the market can use this tested in the laboratory of the Zedler-Institut. For larger volumes, the test systems can also be purchased for testing in your own laboratory.
