A visit to "professional bike breaker" velotech.de in Schweinfurt revealed where the damaging forces are at work on bicycles. When it comes to electric bikes, these forces are even stronger. velotech.de is currently developing a GS certificate for electric bikes in cooperation with ExtraEnergy and SLG.
As part of the supporting program to the ExtraEnergy Pedelec and E-Bike Test, guests visited the firm velotech.de in Schweinfurt on 29 April 2009.
Ernst Brust, head of velotech.de, explained the fundamental principles of his "bicycle torture chamber" to visitors from ExtraEnergy, Bosch, Panasonic, Biketec and Riese & Müller, before showing them how it all works in practice at velotech's almost 20 test stands.
Ernst Brust established the firm velotech.de 18 years ago with over 20 years of product development experience in his pocket, and set out to specialize on testing technology for bicycles. Since then, he has made himself a name with velotech.de - not only as "professional breaker" of bicycles and their components, car accessories and skating equipment (inline skates etc) - but also as appraiser for courts of law and parties involved in standards committees. Today the firm velotech.de, with its nine employees, is an accredited GS test center.
velotech.de tests for individual manufacturers and conducts professional comparisons within product groups, for instance, for well-known institutions, for the German bicycle and car clubs ADFC and ADAC, as well as for specialized magazines, such as Bike, Trekkingbike, Radwelt and Bikesport.
What happens on a test bench
The basis of every test technique is the knowledge of what happens with the product out there in the real world. To set up a test bench, velotech.de fits bicycles with measuring instruments and collects data at the spots on the bikes which real world tests have shown to be taking strain.
In this way, the extent and direction of all main operating stress factors are recorded. About 70% of the damaging forces on a bicycle are shocks coming from the road surface, while the stress from braking constitutes about 20% and the strain from riding out of the saddle another about 10%. On an electric bike, there is higher strain caused by the electric drive unit; how high this strain is, depends on the position of the motor – in the front or rear wheel hub or at the bottom bracket.
Typically, the automobile industry spends several million Euros on a test bench. This is unrealistic for the bicycle industry. A realistic solution is a roller drum test bench for testing the entire vehicle, suspension forks, and wheels. velotech.de has several of these. In addition, there are test benches for handle-bars, seat posts, drive units, forks, brakes, saddles – and even for bicycle bells – just to mention a few examples.
On the test stands, the bicycles or components of bicycles can undergo a variety of tests. Tests can either be done according to the reference value of given standards such as DIN Plus, or until the tested device breaks. A typical test entity stops at 600 kilometer, or continues up to the point where the devices break.
The basic premise for velotech.de is always: "We test the whole, not only the parts of it." That is why one sees complete bikes on most test stands – and not only components – as far as that is possible and makes sense.
Stronger forces are at work on electric bikes
The fact that electric bikes are heavier and are driven at higher average speeds of between 20-30 km/h (instead of 6-12 km/h) means bigger forces work in on electric bikes than on normal bicycles. Add to that, the fact that single pipe frames are mainly used, which are already problematic with normal bicycles and frame breaks may become a threat.
To prevent this from happening and make e-bikes mechanically secure, velotech.de is developeing a special testing procedure and a test bench in cooperation with ExtraEnergy and the testing firm SLG in Chemnitz.
Thomas Bloßfeld, the person who is involved in measuring the stresses on e-bikes at velotech.de, is also a member of the ExtraEnergy Test team.
Goal: GS seal for electric bikes
As part of the new testing method introduced by ExtraEnergy this year, every bike is tested in Schweinfurt, after completion of the test rides in Tanna. There they are taken for measuring the damageing forces, further develop a specialized testing bench and determine the state of technology play – and to create a basis for future GS tests.
The goal is to issue GS certificates for electric bikes from 2010 and offer this as another option to manufacturers in the ExtraEnergy Test.
Text and photos: Susanne Bruesch
Translation: Christoffel Volschenk
Last updated: May 12, 2009