MIT Aluminum Bicycle Project 1974 (2016)

Aluminum frames and history

• Modern aluminum road frames (e.g., CAAD8/9, Klein) are cited as the peak of light, stiff tubular aluminum design.
• Several posters recall older aluminum and aluminum–carbon frames; many failed at glued joints rather than tubes.
• Historical aluminum bikes from late 19th/early 20th century are noted, raising questions about what exactly was novel in the MIT project.

Magnesium and new alloys

• Classic magnesium frames (e.g., 1990s cast designs) are remembered as crack‑prone; casting is blamed for brittleness.
• Modern extruded or welded magnesium frames exist and some riders report good long‑term use, though welds can look rough and ride quality harsh.
• A new class of extruded nano‑laminate magnesium (LPSO alloys) is discussed: higher strength/stiffness than common aluminum, good damping, but strong corrosion issues and no commercial-scale production yet.
• Joining extruded Mg is an active research area; techniques like friction stir welding, brazing, and adhesives are mentioned with caveats (corrosion, inspectability).

Frame materials: carbon, steel, titanium, bamboo

• Carbon is praised for tunable stiffness/compliance via layup and for aerodynamic shaping; several see it as the best performance option.
• Titanium has a strong fan base but others doubt its comfort claims and note welding difficulties and cracked frames.
• Steel is liked for ride feel and durability; ultra‑light steel builds exist but are expensive and can be flexy/dent‑prone.
• Bamboo is viewed as an interesting “green” option but aerodynamically and weight‑wise inferior to carbon for high performance.

Ride comfort and vibration

• Multiple comments argue frame material contributes little to comfort; tires (width/pressure) dominate.
• Suspension seatposts and exposed seatpost flex are cited as highly effective in reducing vibration.
• Claims that aluminum or titanium “ride harsh/soft” are compared to audiophile myths: strong opinions, little data.

Weight vs aerodynamics and performance

• Repeated theme: on track and most road racing, weight matters far less than aerodynamics and rolling resistance; many modern race bikes are well above the UCI minimum.
• Some insist weight has “almost no” effect in constant‑speed track events; others point out small but nonzero effects from rolling resistance, micro‑accelerations, and center‑of‑mass motion on banked tracks.
• On steep climbs and hill‑climb events, weight is agreed to matter more; for everyday riders, body weight often dwarfs frame differences.
• Heavier riders descend faster (higher terminal speed) is defended; counterpoints mention increased rolling resistance and friction but are argued to be relatively small.

Design, manufacturing, and durability

• Larger diameter, thinner‑wall tubes for stiffness/weight are traced from the MIT ideas to modern bikes, though large tubes are disliked aesthetically by some.
• Many modern carbon design choices (oversized head tubes, press‑fit, flat‑mount, UDH) are framed as manufacturing simplifications rather than pure performance gains.
• Aluminum’s lack of fatigue limit is contrasted with steel; catastrophic failure is rare in classic diamond frames but more of a concern in forks and nontraditional constructions.
• Hiking poles and bike frames are used as anecdotes about aluminum fracture vs carbon or desired steel alternatives.

Sheldon Brown site and web nostalgia

• The linked page triggers appreciation for old‑style, content‑rich, stable websites; some note the presence of modest ads and discuss mobile ad‑blocking solutions.