There recently has been alot of buzz/blogging about the belt drive concept unveiled by Trek last fall. I’m not going to go into any arguments about cost/necessity/etc…
Rather, all I’m going to comment on is my own observations with a belt drive 30 years ago. During one summer when I was in grad school and working as a firefighter, I purchased a 1971 Harley Davidson XLCH Sportster. It needed a lot of work, but I also needed a project to keep me out of trouble. As the bike came together, it was actually easier and cheaper to purchase after market parts and customize it.
Once I got it running I took it out for a spin, gave the Mikuni Double Pumper carb a shot of gas, and completely ripped the primary chain in half. That 3-wide link chain connects the drive pulley from the engine to the transmission. It also cracked the aluminum cover that gives the Sporty engine its distinctive look. Since it was cracked, it also leaked even more oil, since the whole chain/pulley system sat in a few quarts of oil.
The solution was to go belt drive. At that time, a company called Phase 3 was just starting to market a kevlar belt and pulley system that replaced the works, and didn’t require any oil. It went together fairly quick, with the only problem that I recall being the teeth on the transmission ring not meshing that well with the starter gear.
But… I immediately noticed that the system was much quieter, and the whole works ran smoother. That big chain inside of an aluminum case made alot of noise and vibration. After that, all you heard was the cackling of those big cylinders through the cafe drag pipes, which was sweet! Not long after that, a lot of custom bikes had primary belt drives, and probably 10 years later, Harley started offering them stock, along with a few models that had secondary belt drives (tranny to the rear wheel).
I don’t know if a belt drive on a bicycle will have the same effect, because I think a properly tuned and lubed bike is pretty smooth. But the aspect of low/no maintenance coupled with an internal geared hub does have a certain appeal. Maybe if they can get the costs down, it will be the wave of the future.