AAAAAyyyyy!!! Bar-end weight theory: As your motorcycle runs,
the handlebars form a resonant mechanical system. That is, the bars
tend to shake at certain frequencies, in certain ways. The lowest
frequency, or fundamental, is a motion you could call, "flapping."
This is where the center of the bars, between the clamps, is
motionless, and the tips of the bars are vibrating most. This is
typically the strongest mode of vibration, and the first one you
should attack. If this frequency is any component of the
characteristic frequency spectrum of your motorcycle, then the bars
start to flap away, bothering your hands. There are three ways to
solve the problem.
- Stop the vibration. Many aspects of motorcycle design can come
into play to check vibration at the factory. Details of crankshaft
design, firing order and angle, mounting location, and
counterbalancers can be used in concert to make for smooth running.
If the engineers who designed your bike were skillful and careful
about these factors, as they affect vibration, you can stop reading
now- you don't need this product.
- Dampen the vibration. From an engineering standpoint, dampening
means eliminating the resonant frequency of the handlebars. The
proper way to do this is with a precisely designed flexible
attachment between the vibrating part and a solidly mounted part,
in other words, a shock absorber. The flexible attachment must be
tuned to exactly oppose the specific frequencies of resonance, so
vibration put into the bars will not be allowed to build up in them
and hurt your hands. Unfortunately, there is no proper way to
dampen the handlebar motion, without a mechanical linkage from the
outside of the bars to the frame of the bike, other than the bars.
There are products out there which purport to dampen handlebar
motion, but they can't technically "dampen" the fundamental
frequency, since there is no linkage between the bar ends and the
frame. That is not to say they don't "work." I haven't tried them,
but I know many who are quite satisfied with them. Why, if they
aren't dampening the bars from flapping? The higher-order harmonics
of the resonant frequencies should be effectively reduced by, say,
inserting a combination of weight and viscoelastic material into
the bars. Due to the physics of the situation, the higher the
vibrational frequency, the less weight is required to disrupt the
motion, and the less solid the mounting point of the dampening
system needs to be. So having a heavy elastomer all the way through
the bars would be great for the higher harmonics, with the internal
motion of the elastomer discouraging the formation of standing
waves in the bars. But that lowest resonant frequency, the flapping
motion, is typically the strongest. For that motion, all that
elastomeric stuff in the bars is only as good as its mass. In other
words, it operates just like plain weights- it lowers the resonant
frequency, and discourages the tips of the bars from changing speed
quickly. This brings us to the last means of vibration
- You could change the resonant frequency. When operating in this
mode, the closer the weight is to the tips of the bars, the more
effective it is. Solutions that involve equal mass throughout the
length of the bars, have only a fraction of their mass working for
the cause. The rest is dead weight. As a rule of thumb, any mass
between the first two curves of the bar from center, is dead
weight, and any mass at the tips of the bars is fully effective.
That's why our bar-ends are designed to maximize weight just
outboard of the bars. They are 12.5 oz. per side or more, and every
ounce hits home.