Building my own jogger

This is a long post, I hope I won't bore you guys. It's kind of a semi-document of what I was up to since the beginning of this year.

Here is some background. After finding out my wife carrying twins in the beginning of the year, I was excited and nervous. My major concern is rather I could be a father of two or not. Indeed, this is the question I always ask myself before we even plan for kids. (That was part of the reason I got into endurance sport. Mostly related to the inspired video from Team Hyot. But thats another story)

I was stressed not because of everything I have to prepare. I feel like I am not preparing enough. Baby class, buying all necessary baby stuff, prep for baby room, baby CPR course, I have done what everybody should do. But that doesn't give me piece of mind. I decided to start this project... a special gift for my twin girls. 

This may sounds weird... I remember I told myself when I ran the first marathon; If I can finish a marathon, I can do anything. For some strange reason, I feel that if I can accomplished this project, I can be a good father. 

So this begin.

I start off by... dreaming. After seeing all those flimsy stroller I am surprise they could pass safety test. With all those bicycle parts in my basement, I start putting some of my thought on paper. With a semi-bicycle junkie + motornut background I conclude with the following design principle:

- one piece solid rigid frame design with mininum flex

- simpliest design (the KISS principle)

- embedded as many already-built quality parts I have as possible (mostly bicycle parts). No point re-inventing the wheel.

- Safety safety safety!

Putting my thought from paper to Google SketchIt, I come up with this:

I didn't draw the seat in, but I have seen strollers with detachable seats, I decided to use them for my build. I get the seat measurement from buybuy baby to determine the stroller width.

Next step, I took a welding class at Schoolcraft community college taught by Rodney Johnson. After learning some basic, I bought some metal. With Rod's permission and guildance, I "execute" my plan with some action:

Start cutting some square tube... the pic show some 45 degree cutting:

This is the plan of how the frame layout. I start realize measurement on paper is different than the actual building measurement.

start building the frame with a regtangle. This is how it tag weld together. I thought it was a piece of cake, however, it takes me forever to make a perfect regtangle. I end up cutting it, grand the metal, re-weld them several times. I still don't understand how I can get 90 degress on all 4 corners but the left beam is 1 cm shorter then the right beam.

The most important point is to have the left and right beam parallel, because thats where the wheel align. I build the whole frame based this rule.

After getting the perfect regtangle, I stick weld them together using some 6103 weld rod. Pic show some of the newbie mistake I made. (another cut and reweld)

Finally have them in perfect regtangle, parallel length, witout any welding flaws (although some weld are ugly but they are structually sound) As for the length compare to the original sketch-up draft, its slightly different because of all the cutting and grinding.

Frame is ready. I thought I am 50% done! But in reality, it is just the beginning. The next thing on the list, the brackets for the handle bar and 3 wheels.

Back to the design studio and start thinking of the wheels, I realized I can't use normal bicycle hubs for the rear wheel. (Duh!) It requires a mounting points for both side of the wheel but my design only attached the wheel to one side. So I source out the following options:

1. lefty hub from cannondale
2. hubs from a tricycle
3. wheel chair hubs

After some research, I give up the lefty hub. Not only because of the price, but also because of the design is always on the left, so it might be a porblem right-mounting the hub in a long run. So thats the first off the list. 

The tricycle hub is also not ideal after some research... most of the tricycle have a shaft involved and it is un-necessary in my application. it might add complixity to have some type of solid axle type of build.  

That said, its still a valid option.

I almost cry when I start searching for wheel chair hubs. Most wheel chair has their own special wheels, which is against my principle of using as much bicycle parts as possible. Then I remember the hand-cycle and sport wheel chair wheels, they are totally different then the normal wheel chair. After some intensive research, I found several wheel chair hubs suitable for my application. Taking the bite of $160 per pop, I end up building my stroller with a pair of Sun Metal GT1000 Alloy hubs.

back to the shop. I start off with the handle bar bracket. Because this is the most complex one. I decided to get the school assisted using a plasma cutter to build the bracket. Too bad I missed some cool pictures the plasma cutter in action. The picture shown below is the circle plasma cutted. I am drilling holes for the handle bar shaft:

I don't have picture of the adapter with all the holes drilled. It takes more times to measure then actually doing the work. But its all well worth. People said measure twice, cut once. I probably measured 10 times and cut once. 

After that I weld it to the frame. however, I run into a heat wrap problem:

Furstated, I fix it by using a pry bar to bend it to proper angle. I didn't buy a handle bar tube yet so I just leave it as is.

hubs arrived. I can start working on the rear wheel bracket:

This is the rear wheel bracket. The material is from the left-over parts of the handle bar bracket. I used press drill to set the shaft hole

Mainwhile, I got the sproke. I start building the wheels with the wheelchair hub:

The finish product. The top tube thing is the shaft for the rear wheel, and those are the adapter plate for the shaft to go in. I made the hole a bit longer so there is some adjustment for the wheel to go forward/backward.

Have the handle bar bracket done, the rear wheel bracket ready, the only thing left is the front wheel bracket. I didn't use plasma cutter for it. Indeed, I start of with a piece of metal and grind it to the shape I want.

Finally bought the handle bar tube. So I test fitted it with the handle bar adapter:

Also have the front adapter finish and weled to the frame. here is a test fit. It takes a lot of time to position both bracket balance so the front wheel is straight

The same accuracy needed for the rear wheel bracket. If any of them out of alignment (not parallel), the wheel will tilt at an angle and it will not go smooth.


After welded the rear wheel bracket, I granded the frame into bare metal, this is how it looks

I thought I am 50% done, but in reality, I am still far away.

With everything in place, I put all the parts together for a test shot.

Now its time to think about the seat. Just happen we start seriously shop for our baby stroller.

We decided tendem is the way to go. However, after trying all the tendem, only one of them can fit into our little 4 dr sedan. We are forced to buy the baby jogger city select:

so I decided to buy the extra adapter for sketchup the draft..

While thinking of the seat, the frame start to rust just by sitting on the garage floor. I decided to paint it. First, I primer it:

I decided to paint the frame yellow. Not because I like yellor a lot, its because its the most visible color... consider jogging across the road with my babies, I want them to be the most visible stroller to the drivers:

Another lession learn. Don't buy cheap spray can. if you want to stick with spray can, buy some decent one. After experiencing with some wal-mart spray can, and a lot of sanding away the awful colors, I decided to spent a few bucks more to buy some Duplicolor can.

paint the handle bar rod as well:

Have them put together. I have the brake and handle bar mock up as well:

As for the brake, I was thinking of putting a set of RSX or the Sora currently on my bike. but then I think about how I lock up the front wheel, I decided to "downgrade" to some walmart brake for now. It doesn't sounds right to have too much brake power that can stop on a dime with babies on board. Beside, it is a jogging stroller. I will be lucky to run 5 mph.

Back to the seat. My major road block is the bracket to fit the adapter. the adapter is in oval shape and they don't sell the bracket by itself. I decided to fab a regtangle just enough to fit the adapter in. My problem... my welding class is over and I no longer have access to a good welder. I decided to try some home tools and see if I can get by. Bought an elbow aluminum piece, a propane torch, and some Alumiweld from Harbor Flight. After 3 days of trial and error, I concluded that Alumiweld is not something structually sound. At least not something I dare to put my baby on. So here I cheat a little bit. I "out sourced" the brackets to some local welder. here is the result:

couple grand worth of miller TIG welder vs $14 worth of Harbor Flight weld rod (or 10 yrs experience of TIG welding vs 3 days of cheapo home brew welding experience)

after getting the bracket, I decided to do have a test fit of the seat:

The bracket is excellent. So I decided to install the seat right away. Then I run into some problem. If I install the seat far to the back, it might tip over because of the weight distribution. If I shift it to the front, the front beam blocking the leg. So.. I picked my poison:

If I redesign it again, I probably move the front bar more toward the front, or backward to the rear and hide it under the seat. But its too late now.

Another minor problem. I plan for the width of the bracket, but never thought of the seat. The seat end up overlapping each other.

After the seat installed, I completed the brake. The brake lever and a 6 feet brake line:

I reverse-mount the brake so that it won't interfernce with the seat, and its better to route the brakeline this way

the brake line was mounted with some high-end advance technology: zip-tie

This is how far it goes for now. I still have 1 week left before the D-day. The only thing left is to true the rims, and to install tires:

Wish me luck to have it completed by this week!