Packard Forum Index » Post-War (1946-54)

If you choose radials in a appropriate size, which is 205/85/R16 to replace a 7.00 X 16, I doubt you'd need alter the stock settings. Radial tires are supposed to have about 10% less rolling resistance and less tendency to wander due to pavement irregularities than bias ply tires. That suggests that keeping to the middle of the caster spec range and the toe out range might give good results with radials, assuming the chassis and springs are in good shape. With the correct bias ply tires, I'd go toward the high end of the caster and toe in spec range for best tracking stability. I'd use the factory camber specs. Cars won't steer unless they are moving, so don't crank on the steering wheel when the car is standing still. Get it moving, even at a very slow creep, when parking, etc. I don't know if a 205/85R16 is available in a lightweight tire outside of the specialty vendors. LT tires are heavier and stiffer than I'd want on a passenger car. I bought an LT 215/85R16 tire to use as a spare. It would not fit the trunk spare tire nest on a '37 120 convertible coupe. I never needed to run it on the ground, but I'm pretty sure it would have rubbed on the front fenders when turning. Based on that, I'm pretty sure a 205/85R16 would fit.

Non-power steering cars can be a little hard to steer when making sharp turns moving at very low speeds, such as when parallel parking. Usually, the steering wheel will turn more easily when the car is moving backward, since backing up effectively reverses the caster angle. Taking advantage of that when conditions allow can make handling the car easier. For instance, if you have to back straight out of a garage or narrow drive into a narrow street, make the sharp left or right into the street, then move the wheel back to center as you are backing the last few feet. That avoids turning the wheel to the extreme left or right while moving forward.

BdeB, somehow i missed page 30 in the front suspension chapter of the brown 1946-50 Packard Shop Manual. Right y'are, thanks. TXG renders some thoughtful theory. I'm running, again, bias-sized radials of the same 7.00 x 15 my car left the factory on when i was earlier running bias tires.

So, unless i hear from someone with a 1942-47 160/180, Super/Custom Super Clipper running Yokohama, Bridgestone, Michelin, etc. bias-sized 7.00 x 15 radials, guess -- and that's the word -- g u e s s i'll split the difference in the 1946-50 Packard Shop Manual.

Many moons ago when I started on my 54, I bought the cheapest 215/75R15 radial from Walmart to make it a roller. The car was very hard to turn a now/low speed.

Many years later, I bought the American Classic Radials 7.60x15.

These are radials that looks like pie-crust edge bias plywood tire with a narrow tread width.

Much easier to maneuver at no/low speed and this is directly due to the smaller contact patch of the tire to the ground.

Those Walmart radials had a very large contact patch by comparison, I swear I thought either the steering wheel or my elbows were going to break before the tires could be turned at at a dead stop.

"Many years later, I bought the American Classic Radials 7.60x15.

These are radials that looks like pie-crust edge bias plywood tire with a narrow tread width.

Much easier to maneuver at no/low speed and this is directly due to the smaller contact patch of the tire to the ground..." //////

This is an important consideration relating to steering effort.

Meanwhile, the 1940-1953 Chilton's Auto Repair Manual lists caster "1 1/2 degrees positive to 2 1/2 degrees positive," against the 1946-1950 Packard Shop Manual's "negative 2 degrees plus or minus half a degree." Why such a discrepancy? Were there reports from the field by the early '50s?

1940-1953 Chilton's gives 1/4 degree negative to 3/4 degree positive camber, the 1946-1950 Packard Shop Manual 0 plus or minus 1/2 degree.
Chilton's toe-in 0 inches, 1946-50 Packard Shop Manual 0 plus 1/16th of an inch, minus 0. So not much variance there. Then why the gulf in caster?

Quote:

They must be using the opposite frame of reference. You can't possibly want negative caster on a car.

Positive caster uses a "negative" angle with the wheels behind the imaginary vertical centerline.

Use the Packard specs for your specific car.
King pin angle is also a factor in stable steering, and it has an effect similar to positive caster, in that it makes the car want to run straight ahead instead of wandering. It is usually fixed and non-adjustable. Some later model cars used more kingpin angle and less positive caster to achieve stability.
It's best to use the factory specs and alignment procedures for your particular car. Personally, I like driving a car that tracks straight, so I prefer more positive caster, and when an allowable range is given, I set it at the maximum.

Worn or bent suspension parts will make setting the alignment impossible.

Some heavy cars without power steering might run a 0 caster or some negative caster to make steering easier. Any lessening of steering effort when turning would come at the cost of poor tracking stability when going straight ahead.