downtube
Diagonal frame member
The downtube is the diagonal tube of a bicycle frame running from the head tube (where the handlebars attach) down to the bottom bracket (where the pedals connect).
It's typically the longest and thickest tube in the frame, bearing significant structural load.
Water bottle cages usually mount to the downtube.
Element thirteen
- carbon fiberReinforced polymer composite
- steelCarbon-hardened iron alloy
- titaniumElement twenty-two
- buttedStruck with the head
welded · lugged · brazed · geometry · oversized · tapered · monocoque · stiffness
Device for changing gears
- cable guideCord management device
- ferruleProtective end band
- housingDwellings or protective covering
Resistance to deformation
power transfer · load bearing · triangle · fatigue · impact resistance · dent · crack · integrity
Resistance through fluid
- airflowMovement of atmosphere
- streamlinedMade smooth and efficient
- teardropSingle unit of crying
- truncatedCut off abruptly
wind tunnel · turbulence · boundary layer · time trial · triathlon
aluminum
Element thirteen
- carbon fiberReinforced polymer composite
- steelCarbon-hardened iron alloy
- titaniumElement twenty-two
butted · welded · lugged · brazed · geometry · oversized · tapered · monocoque · stiffness · compliance
shifter
Device for changing gears
- cable guideCord management device
- ferruleProtective end band
- housingDwellings or protective covering
stiffness
Resistance to deformation
lateral · power transfer · load bearing · triangle · fatigue · impact resistance · dent · crack · integrity · weight savings
drag
Resistance through fluid
- airflowMovement of atmosphere
- streamlinedMade smooth and efficient
- teardropSingle unit of crying
truncated · wind tunnel · turbulence · boundary layer · time trial · triathlon