Israeli design student Dror Peleg has produced a concept bicycle that uses recycled plastics and injection mold technology. Named 'Frii' the bike is completely solid (no tyres, no air) and stems from our desire to find more sustainable ways to travel and to mass produce. Compared to the production of traditional metal bicycle, the process is said to be less labour intensive and more accessible in that it can be customised to characteristics of local industry. The construction of the bike includes an injected saddle, which can be adjusted to accommodate various height or riders, and ribs which are used throughout for strength. A pyramid shaped bottom by the crank is included to stability. See more of the concept bicycle here.