Steerer Tube Storage: Product design and Prototyping

Finished Steerer Tube Storage ready for install.

In the middle of my semi-retirement I found myself having a lot of time and no garage or tools to work on stuff. So this is the first project of mine where all the manufacturing was outsourced. That means this project includes creating real engineering drawings, sending them out for quotation and having a prototype manufactured. I have done this a few times while working as an engineer but things are always a different on a smaller scale and when its your own money on the line.

The Idea:

I have two conflicting thoughts when it comes to mountain biking and general outdoor adventures. 1) I like to be prepared for anything. This means carrying whatever tools, spare parts, snacks and water I may need. 2) I also hate wearing a backpack and having the general feeling of being weighed down. This conflict has usually resulted in various compromises over the years. For mountain biking this means wearing a hydration pack or similar small backpack.

To get away from wearing a hydration pack I have invested in a few bicycle accessories. A generic saddlebag, a Blackburn Outpost Cargo Cage, and occasionally I use a DIY handlebar bag. Of course, this wasn't enough. I wanted permanent storage on my bike that was out of the way and most of all hidden from potential thieves. This way I could leave things on my bike without them being stolen, falling off or ruining my cycling experience. Thats when I started using the empty space found on my bike. I stuffed things inside my handlebars and in the seat tube. Tire levers and spare spokes are good candidates for this. I also wanted to use the empty space in the steerer tube. A steerer tube seemed like an optimal place to store things. It's conveniently located right in front of the rider and close to the handlebars. It's also a standardized size that's fairly universal across most bikes.

Blackburn Outpost Cargo Cage
Holding a 40oz Hydroflask and pump.

Military surplus tool bag strapped
to Jones H-Bar.

Generic saddlebag.

Background & Similar Products:

Now that I had a general idea of what I wanted, I figured I'd just go out and buy an existing product. A few hours of Google searching and forum reading didn't yield much. I found a few similar products but nothing exactly what I wanted. They did however give me some inspiration.

One Up Components EDC
This was the closes to what I wanted for my Steerer Tube Storage idea. It does however have some drawbacks:

Its not for universal storage of things so you're stuck using their multitools. They aren't bad multitools but storing a second multitool isn't the point of this project.
It's quite expensive. Its $59 for the tool system but the required proprietary install tools and other parts will set you back another $60. Putting the total cost at $120 before taxes and shipping.
A potential problem is having to cut threads on the inside diameter of the steerer tube. Something most bicycle manufacturers and maintenance handbooks specifically advise against.

Check out the One Up Components site or this review on BikeRadar to find out more about the EDC.

One Up Components EDC

All In Multitool
Another multitool of similar design to the EDC. Except the All In Multitool is stored inside a hollow crank axle. I have not used one of these myself but I really like the design of it. Very simple and functional. Check out the All In Multitool website or this review on NewAtlas.

All In Multitool

Industry Nine Matchstix
Yet another interesting multitool crammed inside a 15mm axle. It doesn't really relate to my project but was an interesting find and looks like a good design. Check out the Industry Nine website or the review on Pinkbike.

Industry Nine Matchstix wheel axle multitool

Steerer Tube Storage Design:

Now that I had some inspiration I started the design. Making something that can turn a bicycle steerer tube into a storage area is fairly easy. A steerer tube is just an empty tube. All you need are two end plugs so stuff doesn't fall out, right? Not really. The difficult part is incorporating the other necessary requirements, such as:

Retain existing function of start nut and bolt for headset preload adjustment. (Without cutting threads in the Steerer Tube.)
Must be waterproof storage
Corrosion/Rust resistance
Look discreet to prevent theft
Inexpensive to manufacture to keep the sale price down. ($20-$40 range)
Compatibility with most bicycles

The simplest way I fount to meet all these requirements was to design a part that replaced the headset top cap and that slid inside of the existing steerer tube. Then make a slip fit cap with an o-ring to keep it watertight and discreet. (It may sound a bit complicated so just take a look at the pictures or watch the video to see the final product.)

Once this overall design concept was in mind all I needed was some measurement data. Mostly, the inside diameter of various steerer tubes. For this I went to a local bike shop and measured all the forks they had on display. I found 24.2mm was the smallest inside diameter for standard 1-1/8" steerer tubes. The only carbon steerer tube I measured had an inside diameter of 23mm. Some further reading had me thinking that this wasn't the minimum diameter for carbon steerer tubes so I decided to make the Steerer Tube Storage not compatible with carbon setups.

Measurement notes for Inside Diameter
of various bicycle forks.

Drawings:

All of my experience creating engineering drawings had been with Computer Aided Drafting software like AutoCAD and PTC Pro-Engineer. No longer being a student or employed at a large company meant I didn't have access to professional CAD software anymore. Creating professional looking drawings without this software was a bit frustrating. There are many free CAD software packages available (Fusion 360, FreeCAD, TinkerCAD, OpenSCAD, QCAD...) but at the time I had no idea how to use them. I also wanted to get these drawings out for quotation as soon as possible. For me, this meant using Corel Draw.

Corel Draw isn't a dedicated CAD software. It's not designed to create engineering drawings. It was, however, software I had and knew how to use. I had spent many hours creating vector drawings with embedded bitmap images for dozens of projects on my laser engraver using Corel Draw so figured I could make drawings with it too. Despite all of the disadvantages of using Corel Draw, the drawings turned out well. They do have a few problems:

The drawings are not to scale. This makes visualizing the product difficult
There are no solid models. This makes 3D printing or writing CNC code difficult.
The drawings are difficult to update.

Note: Since finishing the Steerer Tube Storage project I have sat down and learned how to use FreeCAD and Fusion 360. It took a bit of time to learn but now creating solid models and drawings is a lot easier. Perhaps I'll do a writeup comparing FreeCAD and Fusion 360 to the professional parametric CAD software I have used in the past. (Solidworks and Pro-Engineer)

Plug Drawing Revision B

Tube Drawing Revision B

Quotes and Manufacturing:

Once I had the drawings finished it was time to figure out how much it would be to manufacture. I posted my drawings on rfqwork.com to get a wide assortment of quotes. This was the only thing I did to get quotes for manufacture. My post on rfqwork asked for two quotes. An initial test run of 3 assemblies, 3 tubes and 3 caps, and then a second production run of 100 assemblies a month or two later. Only buying 3 assemblies at first keeps the initial investment really low. I had also asked for the quotes to include material, complete machining, black anodizing and shipping.

Ultimately I went with a company in China. They had a good presence on Alibaba for quality and their contact person was very responsive and easy to talk to. Another big selling point was of course the cost. They quoted $200 for 3 assemblies including material, machining, anodizing and shipping. They also quoted a very low $6 per assembly for the production run of 100 parts. Attached below is a screenshot of the spreadsheet I used to compare the various quotes I received. The bottom row ranks the quotes in order of preference with some of my thoughts on why.

Dealing with Hanz Manufacturing though Alibaba was actually very simple. There are tons of resources on figure out how to use Alibaba's website and how everything works so I won't go into detail here. I will say I would do it again and not be so nervous about it, nothing but a positive experience.

Spreadsheet keeping track of the various quotes for manufacturing the Steerer Tube Storage.

Drawing created by Hanz Manufacturing.

Pic sent to me from Hanz Manufacturing in China

Inspection Reports:

When I received the first 3 assemblies I did a quick inspection. There were a few dimensions out of tolerance but they were all acceptable as is. Overall the parts looked good. The anodizing looked good inside and out. All the edges were deburred. The parts were also clean and packed well for shipping. Theres not much more I could have hoped for.

Plug Inspection Report

Tube Inspection Report

Tested to see if the Steerer Tube Storage is waterproof

Final Result & Video:

Overall, I was happy with the project. Prototyping was not as expensive as I originally thought. Working with a supplier in China through Alibaba was really easy. The Steerer Tube Storage installed easily and worked well.

Summary:

Designed to maximize storage space on any bike by using the hollow space inside a normal 1-1/8" steerer tube.
OneUp Components makes a similar product called EDC
Corel Draw 7 to make the engineering drawings
RFQwork.com for requesting quotes for manufacture
$253 to have 3 assemblies manufactured in China plus purchasing O-Rings and paying for other shipping fees.
Quality of the assemblies looked good