The X Bike is a folding bicycle concept from MAS Design, who worked on the Strida bike project, and were commissioned by the same company to come up with a small wheel idea. Unlike another of their folding bike creations, which we'll post on soon, this one never came to market, but looks like it contained some intriguing features.
We quote from their website:
• The frame – two main frame elements fold in a scissor action by a skew joint. This allows the wheels to fold side by side.
• Steering – this was by auto-tensioned cables via variable ratio pulleys. These provide a good steering feel to hub-centre steering.
• Drive – this was by internal belt or miniature chain.
• Construction – this uses injection-moulded long fibre carbon and glass shells ultra-sonically welded together. Fusible core, foam and gas injection technologies were also used.
• Tyres – solid tyres were developed as an option with PU versions performing better than pneumatic equivalents.
See also BuyGreen: Small Wheel Folding Bikes.