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Old June 5th, 2011, 07:08 PM   #41
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Join Date: Apr 2008
Location: Chicago, Near the Lake
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Originally Posted by Hyper_Nova View Post
Thanks so much, that is awesome advice, explained in a way I understand! I am experimenting with different washers and cushions, and I think I'm getting there. I cut a pair of purples in half and use them instead of washers now, which seems to work. I'm okay with stability and all, but maybe it will put more pressure on the king pin, since I'm not using retainers (on top of the barrels) now?
Compared to washers (or nothing), retainers tend to cause MORE force to build up as the truck swings out to the max, so replacing them with metal or nylon washers (or just going bare cushion) will likely cause the kingpin to see less overall stress.

However, in addition to the stress from the turning action, there is also a lot of lateral stress from the floor on the trucks that must be transferred through the cushions onto the kingpin and plate. The lips of the upper and lower truck cups will grip and push the cushion sideways to drive its ID against the OD of the kingpin. Eliminating the upper retainer should NOT increase the amount of the truck's lateral movement pressure to the point where it would hit the kingpin.

Be aware though that, especially with the soft Blue Super Cushions, they will become deformed over time and the hole may become enlarged or oval shaped from carrying the lateral truck loads. It is a good idea to inspect them periodically. If they show signs of excess looseness in their fit to the kingpin, then replace them.
The same is true for vertical deformation, and over time the Super Cushions will deform and shorten, more quickly as the amount they are PRE-squished goes up. This means that the pivot pin may also need to be shortened up a bit to match the gradual height compression deformation of the upper barrel cushions over time.

Rollin' on AIR

Last edited by Armadillo; February 24th, 2012 at 05:30 AM.
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