Tricycle Conversion Kit for Wells for Zoe Organisation

Tricycle Conversion Kit for Wells for Zoe Organisation

Tricycle Conversion Kit for Wells for Zoe Organisation

Introduction

As part of my Design and Team building class I had been part of a team of five working with John Coyne from the Wells for Zoe organisation.

We met with our customer John Coyne of Wells for Zoe, He explained there was a problem in Malawi with bikes skidding during the wet seasons, The Terrain was difficult and the roads were in poor condition.

John wanted a means of preventing bicycles from suffering skid accidents and have a bike capable of transporting goods to and from the market and if possible pregnant women to and from birthing centres or a hospital in the event of a difficult birth.

Our team sat down and discussed this. We interpreted this as our customer is in need of a bike that will not fall over, the easiest way to accomplish this is by turning a standard bicycle into a tricycle. The resulting tricycle must be able to tow a trailer and/or carry a basket. We asked our customer how much would they likely be carrying and he told us about 50 kg.

We came up with a project plan and divided up the work. Before we could begin we needed to bring ourselves up-to-date with tricycles, their design and the market.

Tricycles have a variety of purposes. In America and Canada they are used as recreation vehicles, used mostly by elderly people for such tasks as carrying shopping. In Asia and Africa tricycles are used to transport people or commercial goods.

We found that there are three types of tricycle designs.

Upright

The upright resembles a two wheel frame bike with either the front or back of the bike having two wheels. The rider straddles the frame in both front and back upright design, controlling the steering by means of handle bars connected to the front of the trike and peddles it by means of a chain connected to the back.

Upright Design

Industrial Trike with a storage box mounted between the rear wheels

Recumbent Delta

The Recumbent delta works like the upright in that the back wheels are driven by pedals that are linked with a chain to them. The rider sits in a seat and steers the Recumbent delta with handle bars connected to the front wheel.

Delta Layout design

Delta layout: Kettwiesel by Hase Spezialräder

Recumbent Tadpole

The Recumbent tadpole also known as the reverse trike has two steering wheels at the front and one rear drive wheel at the back. Steering would either be linked to by tie rods to the sub axle assemblies or with two handlebars each bolted to a steering tube. This would be through a bicycle type headset and connected to a stub axle assembly.

Recumbent Design

Tadpole layout

The most popular of these designs among people is the Upright design. Tricycle conversion sets can be purchased to convert a two wheel adult bike into a tricycle by means of clamping or bolting on the conversion kit to the bicycle.

For our design we have chosen the upright design and for simplicity and convention we chose to develop a conversion kit that would allow the people of Malawi to convert an adult two wheel bike into a tricycle.

Tricycle Conversion kit

Currently on the market there is a design of conversion kit to turn an adult two wheel bike into a three wheeled tricycle. This design consists of two wheels that are joined by a rotating axle that is enclosed in a sleeve. The sleeve is connected to the bike by either bolting it to the bike or by welding. The sleeve is not one unit but either two halves that are connected by means of a separate semicircle bar welded to both halves. The rotating axle that is connected to both wheels has a six gear sprocket connected to it in the centre of the axle this is then connected to the pedals by means of a chain. These conversion kits cost around €252 euro (American Listed, 2012).

Tricycle Conversion Kit

Example of a Six Speed Tricycle Conversion Kit

After researching different variations of the design for a tricycle conversion kit and coming up with a few concept sketches, the group came to the decision that the design should be as simple as possible, with as few parts involved as possible. Additionally, it was decided that as many parts as possible in the design could be replaced with scrap parts or leftover parts from other equipment in the event that the kit should become damaged. The only parts in the final design that cannot be replaced with immediately available scrap or spare parts are the bearings and bicycle gears.

Conversion Kit Design

Conversion Kit Design

Above is our solid works drawing of our design, some details are as follows:

  • The two points circled in red will contain a ball bearing of Bore ø 10mm and external diameter 19mm. The design is symmetrical, with bearings in the corresponding points on the other side.
  • The bent sections are welded directly to the hollow sleeve, and the top bent section will be welded to the bike frame to allow the frame and sleeve to spread the load of the bike and trailer along the axle.
  • The lower bent section forms the tow hitch.
  • The bicycle gear is welded directly to the axle to provide drive from the chain.

From here we created technical drawings and ordered the material. When our material arrived we began work in the machine shops around the college. We cut the cylindrical parts out and welded them to their respective other.

The following pictures are the end result of our design.

Rear wheels assembly

Rear wheels assembly

Support Bar Welds

Support Bar Welds

tricycle view

tricycle view

Finished tricycle design

Finished tricycle design

Conclusion

In conclusion it was found that although the design seems to be a promising one much more work needed to be completed for it to correctly meet customer specifications.

Problems arose in the prototype stage such as the distance between the two wheels do not allow the rider to operate the pedals fully. The rotating axle would have to be extended to allow the rider to operate the tricycle.

Another issue that arose was using the original gear sprocket on the bike to turn the axel. In practice to successfully get the gear sprocket of the original back wheel of the bike requires a special tool which was not considered in the design stage and may prove to be a difficult item to acquire and from consulting a local bike repair shop it had been discovered that there is no universal gear sprocket tool used to take the gear sprocket off. It was found that the required tool can vary depending on the age of the design and no makeshift tool could be devised.

It would be recommended to build a unit that contains a rotating axel with a gear sprocket, two wheels and two rim brakes. This would mean the people of Malawi could cut off the back wheel from the two wheel bicycle and just weld this unit on instead. A longer chain would also have to be provided instead of using the chain that comes with the bike as this needs to be longer and can be difficult to detach and then reattach.

Overall the project was challenging and enjoyable. It gave everyone in the team a chance to work as a team and work on a solution for a real life problem that a community of people face everyday.

One Response to “Tricycle Conversion Kit for Wells for Zoe Organisation”

  1. Bomani Humphrey June 1, 2014 at 4:34 am #

    I’m looking for a trike conversion kit with 7 gear 26 ” and a 29″trike conversion kit

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