2010-12-31

preventing frame damage in tadpole trikes

12.13: gear/trike`frame/potholes need suspension:
. the trice front-suspension add-on is expensive,
but it's quite likely the frame will be ruined
unless speeds are low or potholes are avoided .

gear/trike`frame/potholes need rider pivot:
12.13:
. the trice already has rear suspension
which helps deflect rider weight from bending frame;
but that doesn't help z-axis rolling
where one front wheel is potholed but the other isn't
and the whole frame falls into a rolling motion
to one side or another .
. if the rider's chair is frozen to the frame
then the rider's weight is resisting that z-roll,
which could increase stress at the cruciform joint .
12.14:
. how rigidly can riders' weight
prevent rolling about z-axis for potholes?
# if rider's seat were not bolted to main tube,
but instead pivoted sideways,
then there'd be less stress on frame during potholes;
# if seat was closer to main tube,
with thick cusion under rider;
then z-axis rotation could happen stress-free
even without pivot .

12.15: gear/trike/replacing front suspension:
. the cheap sure-tech way to stop
frame bends from potholes
is to unbolt the seat from the z-tube,
make a platform that is anchored to
both the z- & x-tube;
and, bolt the seat to that platform .
. if steering doesn't fit with platform,
it can be moved from sides to center .