Did bicycle manufactures build a frame weighing less than one kilogram?

Yes, several bicycle manufacturers have built frames weighing less than one kilogram. These frames are typically made of high-end carbon fiber materials and are designed for competitive cycling, where every gram counts. Some notable examples of sub-one-kilogram frames include:

- Cervélo RCA: The Cervélo RCA frame is made of lightweight carbon fiber and weighs just 795 grams. It is designed for professional road racing and is considered one of the lightest and stiffest frames on the market.

- Pinarello Dogma F: The Pinarello Dogma F frame is made of high-modulus carbon fiber and weighs 830 grams. It is known for its aerodynamic design and is ridden by several professional cycling teams.

- Trek Émonda SLR: The Trek Émonda SLR frame is made of OCLV carbon fiber and weighs 690 grams. It is designed for climbing and is considered one of the lightest production frames available.

- BMC Teammachine SLR01: The BMC Teammachine SLR01 frame is made of high-modulus carbon fiber and weighs 800 grams. It is designed for all-around performance and is ridden by several professional cycling teams.

These frames are extremely expensive and are not typically used by recreational cyclists.