Vibration at speed isn't contact patch, it's an out of round tire, an unbalanced tire, or a bent rim.

Get a good balancing job done, and let them put weights on the outside, too -- the "slight" imbalance required to avoid outside edge balancing weights will knock your teeth out at 80 mph!

Note that all tires are NOT round, and that a hard spot in rotation due to interal dissarangments in the tire can also cause serious vibration.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!