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Nature Boy Disc Dropout:  The Prologue

Hey nerds.  

(I’m just going to assume you’re a nerd if you’re reading this.)

It’s been almost a year to the day I started sketching on this project.  I thought I would bust out those sketches.

Some background:

The Nature Boy was inevitably coming in disc format.  You people were asking for it.  We wanted it for ourselves.

My goal in designing the product was to keep it as close in functionality to the original Nature Boy as possible.  This meant designing a deliberately single-speed dropout/brake dropout system, fender compatibility, and keeping styling cues (the bridge… everyone loves that bridge). 

We also wanted the disc brake to be a positive addition, not a hindrance to the rider.  “How can that be?”  You’re asking yourself as a disc brake fanatic.  “Disc brakes are never a hindrance!” 

When starting this project, we had two scenarios in mind where this would be the case.  Disc brakes on a single speed are a hindrance when you have to remove them to change a tire.  They are also a hindrance when you can’t set them up properly.

“But… but… but… you could solve that with some sort of rocker or sliding dropout!” You’re exclaiming.  Sure we could, but then later you would be asking for a derailleur option on that rocker or sliding dropout.  And then that dropout system wouldn’t be single-speed specific, would it be? 

We like to design scalpels here at All-City, not Swiss Army Knives.  Rocker and sliding dropouts were out the window.

This is the first sketch of this dropout in my notebook with my first notes/concerns:

Sketch 00

The disc mounts are on the inside of the rear triangle to allow the rider to remove the rear wheel without screwing with the brake. 

You can see pretty clearly that I wasn’t a fan of a tensioning screw on the non-drive side.  It was messing up my day.  Ultimately, you have to get a pile of different tools and/or your fingertips in there to tighten the screw.  We figured that out later.  Thrilling conclusion coming.

You will also see that I originally had a dead space in the front several millimeters of the dropout.  This is done because we understand that the first few millimeters of a dropout of this style aren’t utilized, so it is important to have enough adjustability without having to remove a full link considering that dead space.

Here are sketches from when I started looking at what the drive side would look like:

Sketch 01

The drive side was going to be shorter than the non-drive side (which would be long to support the lower brake slot). 

Also, it was clear from the space available that we would have to design our own post mount adapter standard.  I kept dropping different available adapters into the model, but I couldn’t arrive at an artful configuration that gave us the chain adjustment range we needed AND a reasonably small dropout.

001a AC DO

001 AC DO

You'll notice that at every point in my computer model, I have allen wrenches drawn in.  You have to be able to get your tools in there.  Have to.  So it is something we consider right off the bat.


Generally, though, I found myself unsatisfied with the direction the dropout was going. 

And then, one night while dreaming about dropouts, I figured it out. 

To be continued…



February 25, 2014

Nature Boy owner and fellow CAD designer here. Very excited to see some development for a Nature Boy Disc.



February 26, 2014

So how do I remove my rear wheel if I have fenders?  Unless I set my fender up with a lot of extra clearance, the wheel will hit the fender.


Paul Lovell

February 26, 2014

At Frostbike Keith and I thought your disc dropout design was brilliant!  Keep up the great work.


Michael Wang

February 26, 2014

would like a 135mm rear spacing!



March 2, 2014

This is very cool.  Thanks for sharing.

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