Archive for April, 2009

Last weekend I visited the SPEZI and met the guys from SIMPLE is a swiss bicycle manufacturer who developed a carbon belt driven premium bicycle. The SIMPLE bicycles are designed to reduce the maintenance level to a minimum. So it´s a logical approach to use the carbon belt instead of a standard chain. The advantages for city cyclist are:

– No dirty trousers anymore because of chain oil!

– No need to oil the chain. Less maintenance!

– New design possibilities. The chain case is reduced to a stylish spoiler!


carbon belt drive


The modifications on the bicycle frame are minimal. A srew on the rear chainstay allows you to open the frame and to put the carbon belt inside the frame triangel. The SIMPLE bicycle has a mechanical sled on both sides of the dropout to adapt the distance between bottom bracket and rear dropout. This makes it easy to fit in the belt the first time. In case of a flat tire the sled is not needed because there is no big tension on the belt. The depth of the tooth is so high that it accepts a low tensioned belt. 

Here you see how powerfull this drivetrain is:

The optional hubs are the Speedhub from Rohloff and the SHIMANO Alfine.

During the testride I noticed via my legs a smooth feeling! Let´s see how the longterm behavior ot the belt will be! 

The days of the steel chain are numbered. First we´ll see a replacement in the premium city and touring bicycles. Because of the price and the customized frames. But prices for the belt will fall and the bicycle mass market will absorb a new technology!

Gates belt carbon OPTIMIST SIMPEL


Other drivetrain alternatives are discussed in this video… (sorry only in swiss language!).