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Read why your trucks will be awesome with a flat sleeved washer and cupped sleeve washer
This packet is for the recommended downhill setups: Downhill Symmetrical or Downhill Directional.
A symmetrical set up is one where the front is the same as the back. You skate switch it is identical to skating regular.
The cupped washers go under the boardside bushing. The flat washer goes under the roadside bushing.
The idea is the cupped washer gives your boardside bushing extra resistance, tightens it up so you should get some extra stability there. The lean will be coming from the roadside bushing and the flat washer.
A directional set up is a board with defined front and back. So the back is tight using two cupped washers and will follow the front. The front truck is using flat washers all around so it is precise but gives good turn.
The great thing about this kit is you get enough of both flat and cupped washers to experiment and decide what is best for your deck and riding style.