Centre
of Gravity
After
searching for Photos of Greeves Silverstones from the Off road bike
show December 2015 I cam across a picture of an Ariel Arrow that
sported an alloy tank and clip-on bars! It looked well done with
extensions to the front forks upwards to take the clip-ons.
I
look at what people do to their bikes and frequently think that the
manufacturers should have done this. Harley Davidson have always
supplied after market parts for you to customise your bike to your
taste. British manufacturers left it to people like Britax to supply
universal parts that did not fit anything that well. Very little was
available in the 70's and 80's to customise your machine. Things are
now better than ever and you are almost able to get exactly what you
want for the exact model of your machine. I follow the Bike Shed and
what people do to customise their machines. Few are doing chops and
most are slimming down their machines getting rid of the bling and
plastic. Some manufacturers get it right and there is little needed
to get the bike right for you. I particularly like this Ducati
Scrambler from the 80's.
This
is John's bike from the Wey Valley Bike Club.
Back
to the bit about centre of gravity, how much does it affect the bike?
At the upright position, not much but increases with the angle of
lean. How much does your position on the bike affect it? Consider the
handling of an adventure bike against a sports bike. Both can handle
really well but the adventure bike has a much higher centre of
gravity and does not facilitate the knee down riding style so would
there be a difference in cornering ability assuming equivalent engine
power and tyres? Another point is that on an adventure bike you are
further away from the road to start with so to get the same angle of
lean you have to move a greater distance and psychologically feel
your are leaning over so much more. The tyres are still within their
limits of adhesion and the angle of lean is no different. Being
higher on and adventure bike gives you more leverage to be able to
make the bike change direction. Much of this is do with the speed of
rotation of the wheels and engine. Wheels have an immense gyroscopic
action much less so for the direction of rotation of the engine. The
closer you are to your wheels the lesser the effect of moving your
body and legs around. Even if you are quite heavy the impact of your
weight is much less than you think. It is only your upper chest and
head that move the centre of gravity higher. The rest just adds to
the weight of the bike and is relatively low. It is a dynamic weight
that moves and is part of the bike. For reference when you add
luggage to the top box or seat bag and the bike feels much more top
heavy and that is because it is a static weight. It is there and does
not balance itself unlike you as a rider it is also the difference
between a good pillion and an inexperienced one.
The
real difference is in the individual and how and where they position
on the bike. It is about the psychology of the rider and about what
he or she perceives or feels and do they feel good on the day!
My
thought on this is that there is not a great deal of difference so to
prove the point, and I do hope that Triumph will take up the
challenge, take a 1050cc Tiger and a Street Triple with the same
tyres and engine performance and rider and see what happens on the
track where all this can be carefully filmed and analysed. One
thought is that perhaps we should use a Robot rider for this
exercise?
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