An update on the "shimmy":
We collected our NoS Fidelity 11x20 US made Bar treaded tyres from Belgian dealer, Rudi, at War & Peace.
I've fitted four on the Chev, and on the advice of Alain (who drove has CMP from Switzerland to the Guernsey tour in May on them) inflated all to 55 psi.
Just back from 10 mile run and what a difference! Steering improved at low speed and "shimmy" MUCH reduced, but still not completely eliminated.
I can now live with this, and the problem only occurs when can't avoid hitting a large pot-hole and is far more easily controlled than before. On the rare pieces of smooth tarmac on the backroads of Surrey, it ran perfectly.
So what lessons from all of this that might be useful to others?
Well my interpretation based on the
practical lessons of my truck of last 3 months:
1. Unacceptable Shimmy was caused by a number of issues, no one simple fix
2. Wedges are NOT the simple solution. 6 degree wedges made it worse, currently running on 3 degree ones, but only because they appear to make matters no worse (or better!)
3. Adjusting steering box to the specs in manual made a slight improvement and worth doing anyway
4. Slightly worn Pivot Bearings on one side, may have added to the problem, but worthwhile replacing them anyway
5. Correctly adjusted Pivots bearings on both sides to spec in manual, eliminated that possible cause....but no evidence that it was connected to shimmy though
6. New tyres made a MAJOR improvement.
7. Tyre pressures seems critical on my truck. New tyres printed with recommendation of 65 psi; practical user recommendation of 55 psi seems to work well. I had previously tried 35 and 43 psi on the other second hand ex-Bedford RL tyres
8. Wheel balancing: made no difference to onset of shimmy. So a waste of time in my view at speeds I am going at (30 -35mph)
Thats it for now and thanks to everyone who gave advice on this thread.
