View Single Post
Old October 21st, 2011, 10:40 PM   #34
Senior Member
Armadillo's Avatar
Join Date: Apr 2008
Location: Chicago, Near the Lake
Posts: 6,537
Default Understanding how DA45 action geometry makes hokey stops difficult.

In order to do good hockey stops you want to be able to set the wheels NEAR to, but NOT RIGHT AT, 90 degrees to the direction of your motion.
One "feature" of the DA45 action geometry is that as the trucks swing through the motion of their action, the arc of travel traced by the tips of the axle ends swings in a much more horizontal plane, more parallel to the floor than with the steeper kingpin plates. Because the DA45 trucks move in a much closer to horizontal plane, it means that when you try to use them to generate stopping force, the horizontal force being applied to them tends to swing them into a position that puts the axles closer to 90 degrees to the direction of travel. This makes the wheels tend to stick in place on the floor and roll the ankle over.

With steeper kingpin plates, more of the stopping force converts into vertical swing motion of the trucks, and less goes into horizontal swing. The result is that it is easier to keep the axles away from hitting the exact 90 degrees to the slide direction position that has the wheels stop rolling and makes you stick in place on the floor.

Rollin' on AIR
Armadillo is offline   Reply With Quote