Flat / CupThese formfitting precision manufactured washers stay perfectly in contact with your king pin (Randal or compatible) all the time.
Additionally the conic indentation centers the washer as you tighten the nut. The stairs profile holds it at position. Under these circumstances it is impossible for the washer to slip sideways under stress. No more clunking, no more clicking, no more snapping while leaning into the curve.
As nice side effect aluminium is extremely leightweight.
BAMBOO RISERS, 3mm
Ecologically sustainable, extremely leightweight, puristic, beautyful. What more could one want?
Please note that you will need 2 risers (one for each side) to raise up one truck.