choice of the final drive ratio as it is known is essential to make
the most of the potential of the engine. Also in karting this is
very important, both for engines with gearbox, both for single speed
In the competitions the choice of the final ratio, as well as the
characteristics of the engine, also depends on the characteristics
of the track where you race, in fact the layout of the track and the
grip conditions determine the maximum speeds of each curve, and
consequently according to the sprockets chosen the engine
revolutions, it is therefore easy to understand that ideally at the
exit of each corner the engine should be at a speed that allows
makes the most of its torque and power characteristics.
In shifter engines, this is easier because in function of the speed
that you have in each corner, the driver can choose a different
shift gear, but even in this case, being the number of shift gear
limited, it will be difficult to have the perfect shift gear for
With the same engine, as well as the characteristics of the track,
the choice of the final drive ratio is also linked to the
atmospheric conditions and to the ground grip, in fact the
aerodynamic drag of the kart depends both on the air density, both
on the tire rolling resistance, while the power that the engine can
produce is only related to the density of the air.
It is clear, therefore, that the engine power and the resistant
power do not vary in the same way, for this reason when the
conditions change the balance changes and it is necessary to
intervene on the final drive ratio to find the optimal compromise.
HOW CHOOSE THE SPROCKETS OF THE KART
As we have seen the variables that intervene on the choice of the
final drive ratio of the kart ratio are many, so if you really want
to get the most out of your engine in every track, and in any
condition, to include in the interventions of setup also che choice
of the optimal sprockets, is surely a further step to be successful.
In the tests on a specific track it would be appropriate to dedicate
some sessions to identify the best final drive ratio to use, but the
problem arises in the race w.e where in fact there isn't the time
available for testing, but you must choose directly without fail.
In this case the experience and the data accumulated during the
tests are crucial, but often are not sufficient to really make the
best choice, in fact the atmospheric conditions and of grip can be
very different from one session to another, so the choices that were
adequate, are likely to not be true, for this reason the support of
tools and software that can help to take into account of the new
conditions to find the optimal sprockets for the kart are essential
to obtain the maximum performance.
Continuing the reading you can start thinking of putting a important
step for the growth technique of your team and of your job.