Packard Forum Index » V-8 (1955-56)

Usualy rotors are liter than drums. I'm guessing about 25% liter. So ROTATING weight was reduced. Again, this would help to simulate less neg. caster to some degree. Probbaly have less positive effect for smaller drums such as found on the clippers.

KPI is there mostly to aid in tracking the front wheels when steering the car around turns to prevent plowing. As the front wheels are steered, the BOTTOM of the wheel on the INside of the turn tends to tuck up under the car. The wheel on the OUTside of the turn tends to move out away from under the car. THis tends to simulate or cause the inside wheel to turn a tighter radius and the outside wheel to turn a larger radius.

Or to put it another way, the KPI acts like a rear axle differential effect for the front wheels.

This KPI or i think more historically refered to as Ackermann exists on all front suspensions including solid axle and can be witnessed, especialy on F twin I-baem by stepping back 20 feet, looking streight ahead at the front of the truck. U will see extreme angles of each wheelif they are turned to lock in either direction.

Ross, The tread dimension did not change, I am using the original Packard hubs. I just added a rotor.
Jerry

The old PRODUCTION bias ply tires are alot heavier than modern PRODUCTION radials????

I remember the bias ply tires as a lot stiffer and MUCH more difficult to mount/demount than modern radial which almost fall onto the rims.

The only physical change to the brake system has to do with weight and it's location.
The drums, shoes, and other mechanics, were heavy and that weight was centered between the inner and outer wheel bearings.
The disk and caliper is much lighter and is moved inboard over the inner wheel bearing.
There is also a lessening of the gyroscopic effect due to the lighter weight of the spinning disk.
My .02 worth.

John