A wheel-manufacturing technology for rural workshops
Practical Action
and ensures a consistent quality of manufacture.
An assembly jig used for the construction of bicycle-type wheels is shown in Figure 2. In this
case the brackets supporting the adjustable stops may be bolted to the frame at different
positions to cater for wheel sizes from 20-inch to 28-inch.
Wheel designs
Figure 3 shows a basic
range of wheels which can
be manufactured using
the bending device. The
following features are
noteworthy:
The novel concept
of fitting a
standard bicycle
tyre and tube into
a rim made from
25x25x3mm
angle section.
This produces a
low-cost wheel
which is
significantly more
robust and
durable than a
standard bicycle
wheel. Heavier
duty wheels may
be made by fitting
moped tyres into
rims made from
larger size angle.
In the split-rim
wheel the two
parts of the wheel
Figure 2: The assembly jig used for the construction of bicycle-
type wheels.
are fitted either
side of the tyre and then bolted together to hold the tyre in position. It is therefore very
simple to assemble and disassemble the tyre by hand. A similar type of wheel can be
produced to accept motor-cycle tyres.
A variety of rims can be produced to suit different types of tyres, all from materials
which are commonly available in developing countries, such as angle, flat, and round
bar.
Since the wheels will generally operate over earth roads and tracks they will be subjected to
quite severe impact loads from rocks, potholes, ruts, etc. and careful attention to design is
necessary to ensure the wheels are adequately robust and durable. A wheel testing rig has
therefore been developed by IT Transport so that wheel designs can be thoroughly tested and
proven before they are introduced into service. In the rig the wheel is run on a rotating drum
which is fitted with bumps to simulate the type of repeated vertical and side impacts that would
be applied to the wheels in typical service applications. Of major interest in this area is the
testing of the welded joints in the wheel, which have often been a source of fatigue failure in
fabricated wheels.
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