Meridian Quad-Convertible
Converts from Tandem to Triplet to Quad

Tandem configuration

Triplet configuration

Quad configuration

It's almost 13 feet long in the quad configuration and weighs 76 pounds.

When partially disassembled, it fits inside or fully assembled, on top.

Converting from quad to triple mode:

It takes about 10-15 minutes to undo and reconnect three S&S couplers, 4 cable disconnects, add or drop a timing chain, connect computers, and tweak the index shifting.

Click here for a more detailed description (Chuck's Bike Pages) Chuck's page has photos of this frame being manufactured step by step and lots more.