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Discussion Starter · #1 · (Edited)
Anyone ridden both? What's better about 2016 geometry, and is that one OK with 26" wheels, too?

Why the change to 7005 from 6061? Any other factors worth considering , other than absence of FD mount for 2016?

Is there a weight or stiffness difference? (Assuming use of the updated 2015 link)

Edit: I think I found the answer after calling Canfield. 7005 has way higher resilience, or the amount of energy that the material can absorb before permanent deformation. So it seems "bombproof 7005-series aluminum" is in fact a fairly accurate description that they have on their website! Combined with having the rear triangle well-supported on both sides without the FD mount, I think that definitely tips it in the favor of the 2016 frame.

https://en.wikipedia.org/wiki/Resilience_(materials_science)

Here's the material property comparison:
Compare 6061 aluminum to 7005 aluminum

If we consider high modulus carbon fiber, the unidirectional tensile strength is 1000 MPa (N/m^2), multiplied by 0.55% failure strain and divided by 2 to get area under stress-strain curve for modulus of resilience, we get 2.75 N/m^2 = 2.75 N*m/m^3 = 2.75 MJ/m^3.

7005 aluminum on the other hand is 17 to 25 MJ/m^3.

If we scale by weight to get specific resilience we're looking at 1.83 for high modulus carbon epoxy and 6.1 to 9 for 7005 aluminum. Standard modulus carbon fiber composites with 1% failure strain and 1500 MPa unidirectional strength gets a value of 10.5 on this measure, which is even higher than 7005, but this comparison probably doesn't mean much on a bike since the layups and failure mode are more complex.

...Either way, I probably shouldn't be writing anything that makes aluminum possibly look favorable in certain situations since I work in composites, haha

Edit: wasn't considering that yield strains of aluminum are also very low, less than 0.5%. Carbon fiber definitely superior so looking forward to the Carbon Balance.
 
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