- 5

tested also on country roads and muddy roads to see if the

machine could be used for agricultural purposes in addition to recreational riding . The tests were repeated again and again

to ensure themselves that the vehicle could run on such terrain



easily and safely . As the testing progressed , other specifica tions began to develop .

During Mr . Takeuchi ' s continual modification and

testing of the prototype , certain other aspects of the ATC

vehicle became clear .

The thumb - throttle , for instance , was

decided upon because it gave the rider the ability to hold firmly

onto the handlebars and make body movement inputs while applying

constant pressure to the throttle .

The differential , which had been considered for the

off - road vehicle as it is applied to on - road vehicles , met with

an obvious problem .

In driving any vehicle on an off - road

terrain , one wheel can inadvertently leave the ground

momentarily , because of the bumpiness and uneven character of the

terrain .

If a differential is used , it can allow the wheel not

in contact with the ground to speed up . When it regains contact

with the ground this driving wheel will be moving at a different rate . This can cause a yawing torque , which may disturb the

rider and his control of the vehicle . Mr . Takeuchi discovered

that by shifting one ' s weight in a natural way during a turning

maneuver , a turn can be negotiated very easily . With a live rear

axle between the driving wheels , both wheels will be turning at

the same rate , whether or not they are in contact with the ground