"We've got good news. All bikes still work", echoed the boss himself, when we arrived in Ludwigsburg to inspect the endurance test bikes. And, as a matter of fact, the running performance of 6000 to 8000 kilometres in daily use was not evident on any bike at first sight.
The team members of the Zedler institute kept the four Stevens bikes almost two years long running and in turn under controlled conditions. This ensured an identical load on all bikes. With every change of the rider the bike was serviced and properly maintained (see also TREKKINGBIKE 1/2012, p.86, and www.trekkingbike.com, search: Dauertest (endurance test)).
"First of all we’ve lengthened the mudguards. Nearly all manufacturers mount too short mudguards. For this reason spray from the front wheel affects the feet directly", explains David Heil, the recording team member. He is the man of practice who has recorded all changes with mileage and date. In addition, all wheels were fitted with axles safe against theft and one-sided click pedals comfortable for daily use. The paddle grips slided on the Primera handlebars were removed at once. They turned during the ride and were replaced by Ergon grips with bolted clamping. 6000 kilometres later, however, the expensive grips no longer have a fresh look. They are shabby, their surfaces being worn and brittle.
"At the beginning each bike had lots of flats", reports Heil. The search for the cause revealed that Stevens had fitted all bikes with a too small rim tape. These shifted to the side, sharp edges of the spoke holes pierced the inner tube. Good to know what you’re riding around with under your inner tube. A short test ride with each bike proved correct the welcome greeting. All bikes are still running well, changes to the condition as new are in most of the cases hardly noticeable. They become only clear in the direct A/B-comparison.
What follows is workshop and photographic studio. The dismounted components undergo critical examination by all parties involved. What strikes again and again is that there are no or hardly any effects of wear. Both Shimano hub dynamos, i.e. a cheap one N30 and a high-value N80, were spotless inside. Neither humidity, nor dust; even the original grease applied during production was completely as new.
The cone bearings of the hub dynamos and the XI-rear axle were comparably clean and nearly as new. The Japanese apparently make a good sealing job. However, although the winter 2012/13 had been icy, there had been little snow in the test region around Stuttgart. The bikes that had been used all winter long remained largely unaffected by corrosive salt water. This had a positive effect on the service life of the gears, the chains and the forks.
A surprising finding was, however, that all chains had nearly the same wear rate, no matter whether driven by an internal gear hub or a sprocket assembly. “This is evidence for a high-grade material and manufacturing accuracy. It’s apparently more the chain tension than the diagonal run that causes the wear”, resumes Dirk Zedler. This complies also with the results of a TOUR chain test, i.e. that the change towards 10-speed chains had not increased the wear rate. The intervals for the replacement of chains and brake pads also depend a lot from factors, such as rides in the rain, cleaning and care intensity. Tyre wear could not be measured. All treads were still in sound condition, i.e. an indication for the fact that the test team had the tyre pressure always under control. That was the conclusion of this long-term observation. Today’s bicycle technology is good. Appropriate maintenance and care can keep the function alive for a very long period of time.
The untouchables
Dirk Zedler, officially appointed and sworn bicycle expert, head of testing institute and in 2011 1st place in the statewide competition awarding Baden-Wuerttemberg’s most bicycle friendly employer and the 2nd place in the national competition awarding Germany’s most bicycle friendly employer, and his fellow testers - without exaggeration it can be assumed that they have expert knowledge, qualification and professionalism in respect of bicycles.
Since spring 2011 Zedler and his team have kept moving on behalf of TREKKINGBIKE all sorts of bicycle technology on four different Stevens bikes day in, day out and in all weathers through all in all exactly 25,927 meticulously recorded every day and spare time kilometres.
Author: Jochen Donner
