Cargo Bike for Short People

grabcad

Please COMMENT and make suggestions for DESIGN IMPROVEMENTS!!! ‘Lowcost’ is not the same thing everywhere. During my travels, I frequently see overloaded bicycles and I know that the big, fancy cargo bikes where I live are not very affordable and too tall for many folks who need them the most. It is this observation and my background as a mechanical designer and bicyclist that inspires me to design a simple vehicle that will be affordable and helpful to people there and elsewhere. My intention is to document a design that will not be protected by patents or licensing. I hope for collaboration, but I want to maintain tight control over the design until I find an organization that can properly maintain and improve it in the future. As of 2018/02/28, the design specification is as follows: • Affordable • Very common fabrication technologies • Significant opportunities for end-user customization • Opportunities for manufacturers to sell complete bicycles • Opportunities for manufacturers to sell frames • Optimized for short people • Step-through frame • Facilitates the use of very common and inexpensive components • Efficient repair and servicing of the rear wheel without unloading a bicycle loaded with cargo • Easily extended and modifiable kickstand (width) to allow unbalanced loading of cargo • No derailleurs (Compromise in favor of robust kickstand) • 26-inch wheels • 135mm rear dropout spacing • ( New spec’) Off-the-shelf head tube, bottom bracket, and seat-post collar • ( New spec’) Rear disk brake mounting points per 51mm International Standard • ( New spec’) Rear stay clearance for fenders • ( New spec’) Kickstand to be extended and retracted without dismounting • ( New spec’) 28.6 mm (1-1/8") seat tube outside diameter; 27.2mm seat tube inside diameter An earlier idea I had was to have manufacturers produce kits of components such as the head tube, down tube, seat tube, kickstand, etcetera. Kits would then be finished in simple welding shops that also fix cars and trucks, for instance. Although the idea might result in the lowest possible cost for end users, I saw too many possibilities to optimize the design in ways that will probably make the finished bicycles safer, lighter, and perform better, justifying a slightly higher cost, even in low-income areas. Therefore, I have set that idea aside for now. The design of optional modifications such as passenger seats and cargo carriers may be provided informally as part of this project. Such documentation will not be controlled with any formality. The design is also exclusive of components such as handlebars, seats, peddles… (Basically, components that are already designed and inexpensive.) GrabCAD contributors may see some of their models in the assembly. If this is objectionable, please let me know. If you don't mind: Thank you! My experience with product development and quality forms my conviction that the most important component of any design package is the design specification. I am hoping that people who can absorb and articulate the needs of the people of the Yucatan and similar places and then help me write a revision-controlled design document will ensure the optimal outcome of the project. At this point, the design specification is as follows: • Affordable • Very common fabrication technologies • Significant opportunities for end-user customization • Opportunities for manufacturers to sell complete bicycles • Opportunities for manufacturers to sell frames • Optimized for short people • Step-through frame • Facilitates the use of very common and inexpensive components • Efficient repair and servicing of the rear wheel without unloading a bicycle loaded with cargo • Easily extended and modifiable kickstand (width) to allow unbalanced loading of cargo • No derailleurs (Compromise in favor of robust kickstand) • 26-inch wheels • 135mm rear dropout spacing • ( New spec’) Off-the-shelf head tube, bottom bracket, and seat-post collar • ( New spec’) Rear disk brake mounting points per 51mm International Standard • ( New spec’) Rear stay clearance for fenders • ( New spec’) Kickstand to be extended and retracted without dismounting • ( New spec’) 28.6 mm (1-1/8") seat tube outside diameter; 27.2mm seat tube inside diameter I have some ‘Wish List’ items: • It would be great if the design could accommodate some internally geared hubs. Hopefully, the design already does accommodate some current models, but I don’t have enough experience to know with certainty. Maybe someone can look at the design and give an informed opinion on that. • I think that the kickstand is going to be sub-optimal because it is so far back on the frame. Maybe someone will see a way to improve it. I have spent, literally, days working on the kickstand and I am just okay with the present design. • I am also hoping to find extension springs for the kickstand and chain tensioner that are already produced in high volume for other consumer products. • A specific shortcoming for me is my lack of knowledge with respect to commonly available tubing sizes in places like Mexico and the Philippines. Although fabricators are free to modify the design to use sizes of tubing that are more readily available in various places in the world, I want feedback regarding those sizes that I have selected. Bicyclists who are familiar with the needs of people in places like the Yucatan or the Philippines, etcetera, can review the design specification and make suggestions to improve it. Manufacturing and design professionals may scrutinize the CAD files and see opportunities to reduce cost. Sales and marketing folks might help to promote the project. Once the design is ready to prototype, money may help to execute multiple prototype iterations. All ideas are welcome! Financial help may never be needed if manufacturers get excited about the design. Thanks for finding the end of this.