Next
question that arises is “what’s the difference between the
Rpms’ of the two wheels and whether they ‘related’ to
each other”. The answer is Yes - the rotational speeds of these
two wheels are related to each other and are influenced by two factors
- firstly the ‘Track’ width of the car and secondly, the ‘Turning
Radius’ of the Car – depending on to what degree the Steering
Wheel is turned.
Interestingly, such a ‘relationship’ is not difficult to calculate.
For the sake of simplicity, let’s take the example of a Maruti 800.
The vital stats here are – a) the turning radius - which we assume
to be the minimum it’s capable of (4.4 meters) and ii) the front
wheel ‘track’ of the car - which in its case is 1.2 meters.
Armed with above data, we can now start calculating as follows :
(1) The distance the inner wheel has to travel is the
circumference on the inner circle
i.e = 2 x Pi x R meters.
Where Pi
is ‘Pi’ & R is the turning radius of the inner circle
or = 2 x 3.141 x 4.4 = 27.64 meters.
(2)
Likewise, the distance outer wheel has to travel but keeping in mind that
the turning radius here is higher i.e. the inner radius + the wheel track
-
Or = 2 x 3.141 x (4.4+1.2)
= 35.27 meters.
Since both these wheels
complete their one full (or part circle for that matter) in same time,
it’s obvious again that the outer wheel has to cover more distance
in the same time.
Therefore, the ‘relation’
between the two wheels’ speeds is such that outer tyre travels/rotates
(35.27/27.64) = 1.27 times faster than the inner one !
Let’s call this
ratio as ‘K’.
The point
to be noted here is that it’s not just the front but also the rear
wheels have to travel at such different speeds.
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