MIT Aluminum Bicycle Project 1974 (2016)
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MIT Aluminum Bicycle Project 1974 (2016)
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Re: MIT Aluminum Bicycle Project 1974 (2016)
#2The pinnacle of the modern tubular aluminum road bike frame was probably reached with the cannondale CAAD8 and CAAD9 frames, which could easily be built into UCI-illegal-weight bikes using expensive components and wheelsets.
stripped example: https://weightweenies.starbike.com/forum/viewtopic.php?t=153...
https://www.reddit.com/r/cannondale/comments/1d9nind/2009_ca...
Re: MIT Aluminum Bicycle Project 1974 (2016)
#3> He ruled out magnesium, which is best per unit weight in compressive buckling but is brittle and difficult to extrude.
There's a fascinating, and very new, class of nano-laminate magnesium alloys called Long Period Stacking-Ordered (LPSO) alloys. These are very lean -- the standard version is 97% Mg + 1% Zn + 2% Y -- and they have outstanding mechanical properties. At an equal weight, they're much stronger and stiffer than 6061 aluminum, and the kicker is that this is generally true only if they're extruded. If they're not extruded, the laminate-like grain structure doesn't form properly.
Could make excellent bike frames.
Magnesium corrosion would still be a problem, though. I got some LPSO-Mg samples from Fuji Light Metals, in Japan, and they were quite badly degraded within weeks.
Re: MIT Aluminum Bicycle Project 1974 (2016)
#4Favorite road bike I’ve ever owned was the aluminum Klein Quantum Race designed by Greg Klein.
Re: MIT Aluminum Bicycle Project 1974 (2016)
#5It's interesting that trackies in the 70s were trying to reduce weight that much. I don't think it's perceived as especially advantageous these days. The high-ish end track bike I'm assembling now will be a little over 8 kg (almost 18 lb). We also race much bigger gears (typically 95-110 gear inches in mass start racing, bigger for sprinting) than mentioned in the article (72 gear inches). The position that is considered aerodynamic is also much different -- there is much less focus on getting that insanely low, and instead the focus is on being narrow and getting the forearms parallel with the ground.
Re: MIT Aluminum Bicycle Project 1974 (2016)
#6> He ruled out magnesium, which is best per unit weight in compressive buckling but is brittle and difficult to extrude. There's a fascinating, and very new, class of nano-laminate magnesium alloys called Long Period Stacking-Ordered (LPSO) alloys. These are very lean -- the standard version is 97% Mg + 1% Zn + 2% Y -- and they have outstanding mechanical properties. At an equal weight, they're much stronger and stif…
Can modern material science model this computationally, or does everything have to be observed experimentally? This kind of insane just-so recipe - are researchers just iterating on hundreds of thousands of different alloy compositions and production techniques or are there strong theoretical principles on which some of this can be derived?
Re: MIT Aluminum Bicycle Project 1974 (2016)
#7> He ruled out magnesium, which is best per unit weight in compressive buckling but is brittle and difficult to extrude. There's a fascinating, and very new, class of nano-laminate magnesium alloys called Long Period Stacking-Ordered (LPSO) alloys. These are very lean -- the standard version is 97% Mg + 1% Zn + 2% Y -- and they have outstanding mechanical properties. At an equal weight, they're much stronger and stif…
There was a magnesium bike frame back in the '90s, made by Kirk:
https://www.elmycycles.co.uk/m21b0s365p4804/1992-Kirk-Revolu...
https://www.bikeforums.net/classic-vintage/1279777-kirk-prec...
https://www.independent.co.uk/news/uk/magnesium-in-frame-to-...
https://www.flickr.com/photos/11521783@N05/albums/7215764801...
A friend had one. It cracked.
Re: MIT Aluminum Bicycle Project 1974 (2016)
#8> He ruled out magnesium, which is best per unit weight in compressive buckling but is brittle and difficult to extrude. There's a fascinating, and very new, class of nano-laminate magnesium alloys called Long Period Stacking-Ordered (LPSO) alloys. These are very lean -- the standard version is 97% Mg + 1% Zn + 2% Y -- and they have outstanding mechanical properties. At an equal weight, they're much stronger and stif…
How would you fabricate a frame from extruded tubing? Welding would destroy the grain structure.
Re: MIT Aluminum Bicycle Project 1974 (2016)
#9> He ruled out magnesium, which is best per unit weight in compressive buckling but is brittle and difficult to extrude. There's a fascinating, and very new, class of nano-laminate magnesium alloys called Long Period Stacking-Ordered (LPSO) alloys. These are very lean -- the standard version is 97% Mg + 1% Zn + 2% Y -- and they have outstanding mechanical properties. At an equal weight, they're much stronger and stif…
Can modern material science model this computationally, or does everything have to be observed experimentally? This kind of insane just-so recipe - are researchers just iterating on hundreds of thousands of different alloy compositions and production techniques or are there strong theoretical principles on which some of this can be derived?
Its been some time detached from the mat sci folks deeply involved in the space but its both. There is a bunch of theoretical underpinnings but ultimately a lot of throwing darts on the board as well.
Re: MIT Aluminum Bicycle Project 1974 (2016)
#10It's interesting that trackies in the 70s were trying to reduce weight that much. I don't think it's perceived as especially advantageous these days. The high-ish end track bike I'm assembling now will be a little over 8 kg (almost 18 lb). We also race much bigger gears (typically 95-110 gear inches in mass start racing, bigger for sprinting) than mentioned in the article (72 gear inches). The position that is consid…
Not sure if you know about Merckx's bike for his hour record - they did many interesting modifications to it aiming to reduce its weight