Chevrolet C60s - Front Wheel "shimmy"

[cordenj]

Some more progress tonight

Picked up two wheels and "round shouldered" 11x20s from James's LAAT. Identical tyres to my troublesome set, thought it was worth a try to see how they went but was expecting bad shimmy.
Fitted these to the Chev.
Replaced 6-degree wedges with 3-degree versions


Test drive on James's tyres and they performed the same as Neil's . i.e. ran well at reasonable speeds, some minor shimmy when hit a pothole but controllable.
Removed these wheels tonight (as not fit for a long run) and Chev on blocks ready for new tyres in a couple of weeks.

So it means that my first replacement ex-Bedford RL tyres were probably a major part of the issue.....don't know why as look to be a better set than the ones I've trialled tonight.
But truck is also now running 3-degree wedges, new Pivot bearings on one side and numerous other tweaks and adjustments.

As a previous poster suggested....shimmy is probably due to a range of minor issues that cumulatively cause the violent reaction.

Am also going to tweak up the steering box as per the manual. Seems to me I need a 2x2/3" spanner....any recommended work arounds? I see previous owners have used a hammer and chisel, but don't want to follow suit.

Plan to investigate new springs later in Summer/Autumn

Thanks everyone for all the ideas, support and comments