I decided to design my own mini bike. I made this to challenge my 3D modeling skills and also make something that is really cool. I am going to be sharing some of my design details that could be used to design a larger bike.
Step 1: Dimensions
The dimensions need to be relevant to the size of wheels you are using and your height . You can always scale the model after you are done. My design was meant for a small makerbot. The picture attached to this sketch will give you an idea. Make your dimension proportional to this.
(PHOTO CREDIT TO: waterfordbikes.com
Just revolve the tubes by making a center line through the radius of the the tube and make a regular line on the outer edge. Then just revolve that.(make sure your tubes are overlapping so you can cut and edit them out at the end). To make a smoother finish just filet some of the edges.
Step 3: Simulation Stud
I ran a simulation over this part and it did very well. I added 450 pounds after i scaled up the size of the bike and it easily passed. I used alloy steel as my material of choice.