New crank design

On 5/28/2021 3:12 AM, Sir Ridesalot wrote:
On Thursday, May 27, 2021 at 4:07:59 p.m. UTC-4, AMuzi wrote:
https://bikerumor.com/2021/05/21/sra...rative-design/


That looks to be an accident waiting for a place to happen. To me it looks like a very weak design. I wonder too what'll happen when the bicycle goes over obstacles or if there's a twisting force on the crank.

Cheers


"I wonder too what'll happen..."

http://www.yellowjersey.org/photosfr...t/CRANKMD9.JPG


--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971

On 5/28/2021 3:34 AM, Rolf Mantel wrote:
Am 28.05.2021 um 00:09 schrieb AMuzi:
On 5/27/2021 5:01 PM, Tom Kunich wrote:
On Thursday, May 27, 2021 at 1:07:59 PM UTC-7, AMuzi wrote:
https://bikerumor.com/2021/05/21/sra...rative-design/


The problem as I see it is that 3D printing is not a
process without errors. It can very easily have voids and
weak spots.

If you had the idea of using the AI for designing the
lightest possible part supposedly with the highest
strength per weight ratios, what does it matter? Most of
the bikes in the Tour will be too light for the rules and
have to carry compensating weights.

If the UCI, like expected, eliminates the weight limits
it would probably be the end of high end cycling because
it would be like lighting a fuse on a stick of dynamite.
Anyone that is close to it will be injured by the flying
debris.


Yes and no.

Many 3D print pieces do have some severe limits where
strength, torsional resistance or pressure matter. But
sintered pieces from 3D metal powder are failry well known
and of a different class. I don't know but it could well
be adequate and reliable.

I've read somewhere that the aricraft industry is using 3-D
printed Titanium joints which weigh about half as much but
are double as strong as the previous generation of joints.

Rolf


+1

3D additive machining is much more than little plastic gizmos,

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971

Sir Ridesalot wrote:
On Thursday, May 27, 2021 at 4:07:59 p.m. UTC-4, AMuzi wrote:
https://bikerumor.com/2021/05/21/sra...rative-design/

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971

That looks to be an accident waiting for a place to happen. To me it
looks like a very weak design. I wonder too what'll happen when the
bicycle goes over obstacles or if there's a twisting force on the crank.

Cheers


On the other hand, if you chose to, you could keep the weight the same and
design a stronger crank using these methods.

On Friday, May 28, 2021 at 7:23:30 AM UTC-7, Ralph Barone wrote:
Sir Ridesalot wrote:
On Thursday, May 27, 2021 at 4:07:59 p.m. UTC-4, AMuzi wrote:
https://bikerumor.com/2021/05/21/sra...rative-design/

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971

That looks to be an accident waiting for a place to happen. To me it
looks like a very weak design. I wonder too what'll happen when the
bicycle goes over obstacles or if there's a twisting force on the crank..

Cheers

On the other hand, if you chose to, you could keep the weight the same and
design a stronger crank using these methods.
I think that the AI and 3D printing of stronger cranks is a perfectly valid way to model things so that you could use the vastly complex methods of casting such pieces.

When we were going through that business about the steel rotation limiter, I pulled an aluminum casting off of a cheaper Campy derailleur and tried it and it was too thick and could not work. But when I ordered another from Banford Bike, I ended up getting another aluminum casting. I wrote to them three times and never got an answer. I KNOW that they still make this steel piece because all of the 11 speed derailleurs use it. But eventually I tried the aluminum casting and it was indeed different and it appears to be able to work. So I installed it and hope that the Centaur derailleur doesn't fail again.

I could always install a Record derailleur if I get too nervous.

On 5/28/2021 9:01 AM, AMuzi wrote:
On 5/28/2021 3:34 AM, Rolf Mantel wrote:
Am 28.05.2021 um 00:09 schrieb AMuzi:
On 5/27/2021 5:01 PM, Tom Kunich wrote:
On Thursday, May 27, 2021 at 1:07:59 PM UTC-7, AMuzi wrote:
https://bikerumor.com/2021/05/21/sra...rative-design/



The problem as I see it is that 3D printing is not a
process without errors. It can very easily have voids and
weak spots.

If you had the idea of using the AI for designing the
lightest possible part supposedly with the highest
strength per weight ratios, what does it matter? Most of
the bikes in the Tour will be too light for the rules and
have to carry compensating weights.

If the UCI, like expected, eliminates the weight limits
it would probably be the end of high end cycling because
it would be like lighting a fuse on a stick of dynamite.
Anyone that is close to it will be injured by the flying
debris.


Yes and no.

Many 3D print pieces do have some severe limits where
strength, torsional resistance or pressure matter. But
sintered pieces from 3D metal powder are failry well known
and of a different class. I don't know but it could well
be adequate and reliable.

I've read somewhere that the aricraft industry is using 3-D
printed Titanium joints which weigh about half as much but
are double as strong as the previous generation of joints.

Rolf


+1

3D additive machining is much more than little plastic gizmos,

Right. And some of the biggest development efforts occur about seven
miles from me. https://www.americamakes.us/


--
- Frank Krygowski