Building Bike Frames

[BFloFoxRider.]

Sorry for all the random threads from me today. I got to thinking of how they design bike frames. Not as much full suspension but more so hardtails and whatnot.
What do they look for when designing a bike?
What is an ideal material? Strong, light, shiny?
i mean, how the heck do they do it?!?

[allison]

Design engineers (typically those who have a background in Mechanical Engineering) sit down with a program (I totally can't remember the name of the program Justin uses) and design the bike out bit by bit. Maybe someone hand draws it first, but an engineer sits down an actually "builds" it in 3D space and puts all the parts together.

They can do stress analysis tests, etc. within the program (FEA - finite element analysis) to tell where weak spots are that might need to be shored up, etc.

The majority of manufacturers have engineers that work for them full time and design bikes, or change current specs.

There is, however, a school or class or something where Joe Schmoe can go design and fabricate his own bike. I think a guy on emptybeer is at it right now, and others have attended. It's like a week or ten day long thing.


Oh, wait, late edition.. you don't have the attention span to become a mechanical engineer.

[BFloFoxRider.]

Originally Posted by allison

Design engineers (typically those who have a background in Mechanical Engineering) sit down with a program (I totally can't remember the name of the program Justin uses) and design the bike out bit by bit. Maybe someone hand draws it first, but an engineer sits down an actually "builds" it in 3D space and puts all the parts together.

They can do stress analysis tests, etc. within the program (FEA - finite element analysis) to tell where weak spots are that might need to be shored up, etc.

The majority of manufacturers have engineers that work for them full time and design bikes, or change current specs.

There is, however, a school or class or something where Joe Schmoe can go design and fabricate his own bike. I think a guy on emptybeer is at it right now, and others have attended. It's like a week or ten day long thing.


Oh, wait, late edition.. you don't have the attention span to become a mechanical engineer.

no i dont!
haha
is it google sketch up?
i know you can build stuff 3d but im not sure you can test it for stress
i was just curious

[allison]

Originally Posted by BFloFoxRider.

no i dont!
haha
is it google sketch up?
i know you can build stuff 3d but im not sure you can test it for stress
i was just curious

Uh, no. It's like a $7k program or some crazy amount. It's called Pro/E(ngineer).

http://www.ptc.com/appserver/mkt/pro...home.jsp?k=403

And it absolutely tests for stress! I spent many a night in the Engineering building of SDSU waiting for the program to finish it's analysis

Justin used it in college for stuff, and then once he graduated he designed injection molded plastics and used it a bunch for that as well.

I'm actually slightly surprised he's never messed around with it and designed his own bike!


If you are interested, though, do designs up. I'm sure the class is pricey, but you can always check out the info about it.

Who knows. Maybe in 4 years you'll settle down and decide to become a design engineer

[BFloFoxRider.]

Originally Posted by allison

Uh, no. It's like a $7k program or some crazy amount. It's called Pro/E(ngineer).

http://www.ptc.com/appserver/mkt/pro...home.jsp?k=403

And it absolutely tests for stress! I spent many a night in the Engineering building of SDSU waiting for the program to finish it's analysis

Justin used it in college for stuff, and then once he graduated he designed injection molded plastics and used it a bunch for that as well.

I'm actually slightly surprised he's never messed around with it and designed his own bike!


If you are interested, though, do designs up. I'm sure the class is pricey, but you can always check out the info about it.

Who knows. Maybe in 4 years you'll settle down and decide to become a design engineer

well, i've got my own ideas/secrets

[BrewMaster]

Originally Posted by BFloFoxRider.

Strong, light, shiny?

Shiny. Definitely shiny. Shine makes bikes faster, lighter, and stronger.

[Rob]

http://bikeforums.net/forumdisplay.php?f=229

[allison]

DId a little googling for ya:

http://www.littlefishbicycles.com/frame/

http://www.bikeschool.com/frame.htm

http://www.sheldonbrown.com/rinard/carbon_fiber.htm

http://en.wikipedia.org/wiki/Bicycle_frame

[Rockinthecasbah]

start out with a geo you like, tweak it if you want it to steer a little bit tighter or more slack, figure out your optimial chainstay length , figure out what kind of feel/flex you want it to have, steel is a little more flexy then alum usally ti is somewhere in between, but all can be tuned with wall thickness and tubing diameter. Sketch something up , stick it in a program or prototype it build it ride it , tweak it repeat. No reason to try and rebuild the wheel when people have already figured out what works and what doesnt for you. Just ask the r+d department at any motorcycle company youll find other companies bikes torn apart all over the place at different times of the year

[Edog]

What you really need is some sweet welding skills, take a night class at your local college. If you want to build with Alum rather than steel you'll to learn Tig welding I think.
You can cobble together a frame jig. There is a very cool book that I can't remember the name of but I seen it a few Barnes & Noble about frame building. They take a bunch of old bikes show you how to weld & then give you some wacky designs, like a Adult big Wheel, that crazy bike with the hinge in the frame.
You can actually buy a lot of the parts pre made so you only have to worry about tube length & welding. In fact you could buy all the parts from Easton to Glue a Carbon road frame up!
If I had some space I'd be all over it. I'm sure if you took a night class you could build a frame there.
http://www.novacycles.com/catalog/index.php?cPath=35_42
Check these guys out for supplies!

[Rockinthecasbah]

you have to tig aluminum to get a decent weld but you shouldnt start out on a tig , the best thing to start out with in my opinion is a regular stick ARC its hard to get the hang of at first but after you learn mig is easy and tig is somewhat easier ( I suck at tig). If you want to learn how to mig come over when I'm working on the truck you know how to get a hold of me.