Space Horse Dropout Development, Part 1
All-City Product Development works tirelessly to bring to you, the people, the raddest product possible. We thought it would be cool to give some insight into our design process through the blog. We obsess over details- sometimes to the point where they become projects of their own.
So begins the story of the Space Horse dropout…
We chose semi-horizontal dropouts for the Space Horse because of their versatility and functionality- they are the “choose your own adventure” option of the dropout world. You can run them geared or not, typically mount racks and fenders to them, and you can easily get your wheel out without taking off full coverage fenders.
We were pretty disappointed by the off-the-shelf dropouts options available. Since the vertical dropout has dominated much of the upper end of the geared steel frame market for the past few decades it seems that frame part companies have stopped designing and producing functional, classy dropouts of this type. If the dropouts met requirements for frame geometry, rack/fender compatibility, wheel tension capability in a single-speed configuration, ten-speed compatibility, etc., they tended to be of low quality or just not classy enough.
Anything around that was beautiful and functional was proprietary. So, for all of these reasons and because our customers have the finest tastes, we decided that we would design one for ourselves.
All-City was no stranger to proprietary frame parts… our iconic Hennepin Bridge Track End designed by my engineer predecessor, Adam, would be a hard act to follow. Also, gears and racks were relatively new territory for us at the time.
To help illustrate the process from this point, here are some pages from my personal design notebook. (I apologize in advance for the sketches. I draw like an engineer.)
This spread is from the first few days of exploration, where the dimensions first appear, and notes from our first meeting on this dropout. We are a small, very close-knit group here at All-City Cycles so, as you can see, Jeff appears in various forms and moods in my notes.
We were also looking for something that would work across all of our sizes and, because we are huge nerds who like to bring back classic hits to the world, we wanted to draw from a functional strategy that hasn’t been done in a minute.
After a crap ton of obsessive research (paging through bike geek blogs, bike museum books, old catalogs, frame part databases, etc.) and exploration into dimensional requirements, we arrived at dropout strategy where chainstay interface would be more of a lugged socket-style and the seat stay interface of the dropout has a more flexible interface, based off of a Japanese dropout we found from ~40 years ago.
This sketch is modeled after that style… it is the first sketch of anything for this project that looks like a dropout.
Next, you can see a section of the dropout/seat stay interface (bottom right). As you can see from the drawing, we were looking at a domed (as opposed to cylindrical) interface for this area but we were concerned that the more complex geometry would be challenging for proper and consistent seat stay preparation- straight-up mitering would give us the most consistently well-built frame.
This final sketch shows what would end up being the visual direction that we would carry through to the final product. We initially had a single eyelet, which is functional on its own, but we eventually added a second eyelet because of the range of rack and fender options and configurations possible.
Here you can see the initial placement of the drainage holes for our stays. We like drainage holes integrated into dropouts because it kills the need to have holes in tubing close to the dirty areas of the bike. This way, if water gets into the bike, it drains though the stainless dropouts instead of pooling in the bottom of the stays. Also, extra holes, especially near dirty areas of the bike, promote rusting opportunities (we ED coat the inside and outside of all our frames to help prevent rusting too). We eventually moved them to the back of the dropout to keep the outside surfaces of the dropout cleaner.
In the next installment we will move to the three-dimensional process (lots of renderings!)… with neato pictures of the final product brazed/welded to a naked frame.