J
Lateral load CAN increase spoke tension but seldom does. Typically
when leaning the bicycle while climbing or sprinting, standing, even
with large lean angles, spokes are slackened on the high side while
tension does not increase on the low side because it is these spokes
that are carrying the vertical load and are naturally slackened.
The hazard in this is that as the high side spokes become completely
slack, lateral wheel stiffness is cut in half and can easily cause
collapse... and with fewer spokes even more so. Lateral bending
strength of deep aero rims, that can bridge large spoke-to-spoke
distances for vertical loads, is not significantly higher than
rectangular cross section rims, their width being the same.
This all boils down to that spokes in most loading are acting in
tension and that their tension changes behave like compression
elements until the preload is exceeded. At that point they no longer
contribute to the strength of the wheel.
Jobst Brandt
when leaning the bicycle while climbing or sprinting, standing, even
with large lean angles, spokes are slackened on the high side while
tension does not increase on the low side because it is these spokes
that are carrying the vertical load and are naturally slackened.
The hazard in this is that as the high side spokes become completely
slack, lateral wheel stiffness is cut in half and can easily cause
collapse... and with fewer spokes even more so. Lateral bending
strength of deep aero rims, that can bridge large spoke-to-spoke
distances for vertical loads, is not significantly higher than
rectangular cross section rims, their width being the same.
This all boils down to that spokes in most loading are acting in
tension and that their tension changes behave like compression
elements until the preload is exceeded. At that point they no longer
contribute to the strength of the wheel.
Jobst Brandt