Bridgestone Picnica

In April 1987, Popular Mechanics described Bridgestone's Beltrex system as follows: "Unlike the belt-drive motorcycles, which can slide the rear wheel back to keep the belt taut, the Beltrex uses a floating pulley that's cogged to the drive gear.

Tension on the pedal cranks drives the floating pulley forward, taking up belt slack and preventing tooth slippage.

In a review, the Picnica folding mechanism was described as a "case of the frame collapsing backwards on itself, with the handlebars and seat post falling to the top of the rear wheel.

To this end, the main part of the frame is a quadrilateral with a pivot at each corner, and a rear triangle made collapsible by hinged seat stays.

"[4] The Picnica was apparently commercially successful, but was offered mainly in Japan, where it sold for around 35 000 Japanese yen.

On display in New York
A limited number of Picnica folding bikes were imported to Europe. This 1990 belt-drive model in Germany features an extended seat post.
According to the 1985 Bridgestone catalog, the Picnica OPC-14B was the first folding bike with a belt drive.
A Picnica bicycle being folded