When I wrote here about folding bicycles, I looked unsuccessfully for one improvement that would be especially welcomed by business commuters, a grease-free replacement for the conventional steel chain that has defeated alternatives for over 100 years.

It seems I was a few months too early. The New York Times has just reported on a long-deferred desideratum of cyclists, dry high-tech non-metallic substitutes. The price? If you have to ask.... Even frequent cleaning bills are probably cheaper right now.

Don't be too discouraged, though, by the present $2,000-plus level of the new systems. True, added to the expense of high-quality folding mechanisms, they'll initially make portables fit mainly for the remaining hedge-fund crowd. But remember that the very first bicycles, invented by the South German bureaucrat Baron Karl Drais, were hand-built aristocratic hobbyhorses with no apparent value for popular transportation. It took decades of other innovations for the principle to be fully realized. And fans of the steel chain can take comfort from the conservatism of power transmission systems. Over a hundred years after the introduction of electric motors that revolutionized the old water and steam-powered, belt-driven mills, there are still almost 60 companies in the U.S. alone selling leather power transmission belts.