effects of selected mountain bike front suspension forks on handlebar vibration and ground reaction forces
abstract
the purpose of this investigation was to compare the effectiveness of two types of
mountain bike front fork suspension systems for controlling ground reaction vibration at
the handlebar upon impacting a raised surface. a second purpose was to investigate the
effectiveness of these two suspension systems at maintaining ground-wheel contact
following impact
this investigation provided a direct measurement of handlebar vibration and
ground reaction forces at the front wheel. a rigid front end was compared to an elastomer
and a hydraulic suspension system each tested at their stiffest and softest settings. a
single subject was chosen to perform repeated trials over an amti force platform
modified with a 3 cm raised surface. velocity and riding technique were controlled for
reliability and rider weight displacement was measured using strain gauges mounted on
the handlebar.
a shear quartz mode piezoelectronic accelerometer mounted to the handlebar
provided vibration measurements and the amti force platform measured ground reaction
forces. mean curves for acceleration and ground reaction force were recorded and
calculated from repeated trials and used system comparison.
results from the mean curve comparison of the suspension systems showed
reduced amplitude and frequency of vibration at the handlebar and improved
ground/wheel contact time for both elastomer and hydraulic systems when compared to
the mean curves for the rigid front end. statistical analyses supported the mean curve
results indicating significant differences between the rigid and the suspension systems on all variables analysed at the .05 alpha level.
it was concluded that the hydraulic and elastomer systems reduced handlebar
vibration and improved ground-wheel contact when compared to the rigid systems for
this particular subject and bike combination. this investigation supports claims made by
manufacturers of suspension systems, that front suspension improves ground/wheel
contact and reduces transmission of impact energy to the rider at the handlebar.
collections
- retrospective theses [1604]