I took the brake arm from a coaster brake hub that we disassembled for a cargo bed and bent it in the vice put a 3/8″ hole in it and dropped a bolt through it. Done. Simple and effective. The rod end joint is about $6.00, available and salvageable if you have an ATV shop near by. This is just bolted in to the handle of the tongue of the trailer in such a way as to allow it to rotate freely.
This prototype is complete. We have several trailers started that will be ready for delivery in the coming weeks. We will continue development of the trailers for the next couple months. While building the first 2 requested carts. One will be for Stewart, a mobile bike shop of course, and the other for a local urban farmer, as a farm to market cart.
We’re rolling now. We spent the last couple work days getting frame elements ready to assemble on a volunteer day Wednesday. We should have 2 carts for demos and 2 for sale this Saturday at the Marmots’ Meander 2012 event. We are now taking orders for standard and customized trailers. Contact Jim at OCBC or Bart to discuss the details and place your order. All orders will be filled on a first come first serve basis.
This is the first test of the front fork model hitched to a bike. I put 40 lbs of weights and a bunch of frame parts in the tub and rode it around on the cobble stone road next to OCBC took it over the curbs etc. It worked real well the tongue of the trailer allowed you to turn the bike in both directions as sharply as you could safely turn if the trailer wasn’t there. It seemed to add a bit of stability to the bike. I could feel the load on the rough rode but it wasn’t jerky or bouncy or anything. We will be doing more test rides over the next few days.
This design is coming together quickly. We tested this prototype out by having someone 175 lbs or so stand on platform. Next week we will fit this prototype with a hitch and start doing on the road tests. This model will have a recommended payload capacity of 200 lbs but will probably handle more weight than that.
This model will be available within a couple weeks, and will retail for about $200.00 to start. Orders are being taken on a first come first serve basis. Contact OCBC to place order or discuss special uses and customization.
The Front fork rendition of the bike cart is coming together. These pics are of the first prototype ready to be bolted together. I like this design, as it is simpler to assemble, and requires less cutting. We may, in the long run, use the rear frame design for heavy duty carts, leaving the rear triangle as a whole, for added strength and structure, and make the lighter weight carts out of the forks.
Leaving the head tube on makes a nice handle. Using the down tube and seat tube from a step over (women’s) frame, brings the tongue, also the handle, around to the right place to hook up to the rear triangle of the bicycle. This centers the cart, relative to the bike. Allowing the tongue to be adjusted in angle, and height, by allowing it to be rotated, keeps the cargo area level regardless of how high from the ground the handle is positioned. This allows the cart to be easily fitted to different sized bikes, or people.
Using handle bar stems to connect the cross brace to the forks is simple and clean looking. This also allows the cart to be lengthened.
The extra length of tubing at the ends of the cross brace allows the cart to be fitted with a 26″ wheel for a cargo platform. With a 20″ wheel the overall width is 29″ allowing the cart to be wheeled through most doors. a 26″ wheel would make the cart a little less than 36″ which is a standard width for many external and commercial doors.
Rough prototype as of 1/11/2012
The cross brace is made from short pieces of bike frame tube matched so the long pieces slide into sleeves, and bolted where needed, with axle bolts and nuts, from scrapped hubs. The tongue which is also part of the cross brace is made from a seat tube and down tube from a step over frame.
There is a seat post binder sleeve and bolt on one side, to allow the tongue to swivel to fit different frame sizes, and to act as a handle when wheeling the cart around on foot, that way the cart acts as a wheel barrow and the load doesn’t have to be transferred when going inside or walking around a farmers market or some other venue that would allow the use of the cart while walking. We’re not sure if the seat bolt binder set up will work yet the tongue may have a tendency to rotate under load, it may have to have a removable pin to lock it in place when it is attached to the bike.
The next step is to make a connector which swivels or rotates both horizontally and vertically, to allow the cart to turn bike and rotate relative to the bike. These can be purchased from trailer manufacturers and through bike shops, but we’re going to try making them out of scraps.