47-55.1 Kingpin/spindle bushing question

[dsraven]

If you think about WHY there is a roller bearing there it makes sense to have one. And the shims above the axle just take up the extra space to stop potential clunking and hammering on that roller bearing. But, then if you overthink it, you can see why, back in the day with not so smooth roads and trucks that carried along of weight, it also made sense to use washers with grease grooves. A roller bearing may have taken some good hits and had flat spots on the rollers.