Coaster Brake Bike is Done

For some reason, I decided I wanted to model a coaster brake bike like I had when I was a kid. It didn’t turn out much like my bike, as I put a 24″ rear wheel on it, a big ol’ sissy bar, and a springer fork. This was really just a modeling exercise apart from book writing. The main technical challenges in this were all of the details in the coaster brake hub, which I showed in previous posts, but also the wheels. I put myself through college in part as a bicycle mechanic, and I’ve laced a few wheels in my time, but never a 24 spoke 24″ wheel. Spokes tension up and bend a lot when installed, which is difficult to do in CAD, especially when you have several different positions in a cross pattern. So the rear wheel is cross 3, and the front, with no brakes is radial.

I used 5 different configurations for the spokes. 4 for the various angles (measured from the head of the spoke) and lengths for the positions of the spokes in the rear wheel, and 1 for the front. The front is spoked radially, and all from the outside, so it only needs one angle and one length. The back uses different lengths on the right and left, shorter on the drive side, and longer on the non-drive side. And then it needs 2 angles because some spokes come from the inside of the flange and some from the outside of the flange.

Actual springer forks worked different from this design. This pivots at the fork crown rather than on a 4 bar link at the front wheel attachment.  Plus, the frame on this is slightly bigger than a kid’s 20″ bike. This one was designed for adults with the larger rear wheel.

Originally I was also going to put an internal 5 speed in the hub (internal gears and brakes), but didn’t get to it this time. I’ve got maybe 8 hours into the rear hub, and maybe 10 into the rest of the bike. It might need a kickstand, and actual connection clamps from the seat to the seat post and the sissybar. I did add a license plate, though.

I did this because I just wanted to do an actual modeling project after finishing the book, and also to make sure I could use all of the things I wrote about in the book. Plus, you know, I’ve got to build a body of work post-sabbatical to prove to myself if no one else that I can still do it.

There were two big annoyances during this project. One was flipping between SW and other windows. For whatever reason, I stopped using the ALT-TAB thing because it’s not as simple as it used to be. I started using the Windows task bar, because I would have multiple SW windows, and I could select which window I wanted to switch back to. But there’s this weird thing where you have to preview the specific window you want to open for like 5-10 seconds or it won’t open. I don’t know if this is a Windows thing, a SW thing, or a Matt thing, but it became very annoying and a big waste of time. To use ALT-TAB, you’d then have to Ctrl-TAB to the correct window. So both ways were a little annoying. Of course trimming it down to just having the one window I was working with open at any given time is maybe too disciplined an approach for me.

Photoview 360 is pretty much as it was 5 years ago. SW always had a difficult time settling on a usable renderer. The images created are very underwhelming, and don’t really inspire me to try to make more.

The past several years I’ve been using Keyshot, which by contrast is pretty good, and makes nice images. Much easier to edit and set up. I guess the goal here is to annoy users of PV360 into buying the Visualize thing.

Next stop for me is plastic swoops. Probably some sort of farsical hand-held medical device.