pic: Carbon fiber monocoque drivetrain Top view

[gblake]

Originally Posted by gblake

...
Carbon fiber bicycle frames are made of roundish tubes, not boxes.

Originally Posted by Bryce2471

... Chief among which is probably aerodynamics.

Maybe. Maybe not. I think the jury is out unless/until we talk to someone who has crawled through all the trade-offs (including buyers' psychologies) in the real world.

[JesseK]

Originally Posted by gblake

Maybe. Maybe not. I think the jury is out unless/until we talk to someone who has crawled through all the trade-offs (including buyers' psychologies) in the real world.

If we presume there are bumpers on the sides, then we can presume an impact will spread pretty evenly across the outer edge vertical face. If that were rounded, the force of the impact would be more concentrated.

I forget the VA/NC team who usually does carbon fiber. They've been next to us in the pits a few times, so I got to talk to them. IIRC, a lot of their super structure was rounded tubing. The edges of the drive train frame were filleted with a small (0.25"-0.5") radius but otherwise the faces were straight.

On the plus side, this stuff is so lightweight you can disassemble the vast majority of the superstructure into COTS parts and the carbon fiber frame while still being under the withholding limit. The downside to that is that you're spending all day on Thursday re-assembling...

[Electronica1]

Originally Posted by JesseK

I forget the VA/NC team who usually does carbon fiber. They've been next to us in the pits a few times, so I got to talk to them. IIRC, a lot of their super structure was rounded tubing. The edges of the drive train frame were filleted with a small (0.25"-0.5") radius but otherwise the faces were straight.

The team you are looking for is 1829 "Carbonauts".

[gblake]

Originally Posted by JesseK

... The edges of the drive train frame were filleted with a small (0.25"-0.5") radius but otherwise the faces were straight. ...

That's what I was imagining, not 100% round. Also not 100% sharp(ish) corners.

[EricH]

Originally Posted by gblake

Maybe. Maybe not. I think the jury is out unless/until we talk to someone who has crawled through all the trade-offs (including buyers' psychologies) in the real world.

I would put "stress concentrators" as a (singular, but definitely not the only) reason that sharp angles aren't used with carbon fiber bike frames. Sharp angles tend to try to take all the stress they can, in general... and in the case of carbon fiber, it'll be very not pretty when (if) it breaks, particularly if somebody happens to hit the break. There are ways around this--like more material on the sharp corners--but it's generally better to not have the corner quite so sharp in the first place.

[JesseK]

Ah - found them - 1829, the Carbonauts:
http://www.thebluealliance.com/team/1829/2015

Looks like for 2015 they went to Aluminum. I'll see them this weekend at Rumble in the Roads, anyone have any specific questions for them?