Reprinted from the LA Times

The 24 Hours of Adrenalin Solo World Championship is often a grueling showcase for the world's toughest bikes and riders, but the July event in Canmore, Canada, was something special.

Greg Martin, a 37-year-old firefighter from Ketchum, Idaho, won the single-speed division (and came in fifth overall) on a bike that didn't have a chain. It used a smooth, silent, carbon-polyurethane belt — similar to that of auto transmission and timing belts — to prove that belt-drive, a new technology unknown to most bikers, is ready for prime time.

With dedicated chain rings required to match the studded belt, this Carbon Drive system from Gates, a leading motor-vehicle belt supplier, isn't cheap — and it can't be used with derailleurs. But the system offers a number of benefits over the 150-year-old chain. It's lighter; doesn't use grease; requires no maintenance; won't break, stretch, rust or fall off; and, best of all, it offers a pronounced improvement in "engagement" — the millisecond it takes for the bike to react to your pedaling forces.

Each of the four review bikes below (reflecting categories that are best suited to belt-drive) delivered an instant reaction that my cycling buddies and I found rather exhilarating.

— Roy M. Wallack

To read the reviews of several models, go to the LA Times