If I were stuck somewhere and needed to have some sort of major work done, what type of metal is the frame made from?
With the exception of the titanium beam on the Air-style bikes, all of the Bike Friday frames are made of 4130 cro-moly. Cro-moly is a steel alloy containing chromium and molybdenum. The inclusion of chromium and moylbdenum give the alloy characteristics which make it an ideal bicycle frame material. It is extremely strong yet flexible, and as such can stand up to the rigors of cycling.
In the factory, Bike Friday frames are TIG-welded and brazed. These are the best methods of joining cro-moly. In a pinch, in the middle of nowhere, a Bike Friday frame could be repaired with oxy-acetylene welding, MIG welding (wire feed), or even SMAW (arc) welding.
Let’s hope you never need to know this, but if you were ever really stuck somewhere this could help. Customers with frame breaks in far-away places have been able to get their rigs repaired.