I would suggest you look for the Chrysler MasterTech program on front end alignment. It illustrated ONE great thing about Chrysler front end geometry that Ford and GM do not have. Camber change in the corners. At stock settings.
In a left hand turn, for example, the outside wheel goes into negative camber, as the inside wheel goes into positive camber. As the car leans, the tire sidewalls still remain perpendicular to the road surface. With the use of a front sway bar, less lean and MORE bracing of the sidewall against the cornering loads. With A GM or Ford front suspension, no camber change so as the car leans, so does the outer tire, into effective positive camber.
On the GM front suspension, adding caster to the mix gives something of the above-mentioned Chrysler effect to the actual geometry. Better bracing the tire sidewall against the cornering forces. On my '77 Camaro (F42 w/WS6 sway bars), I told my alignment guy to "max caster" (to whatever value he could get), minimize camber (in specs), and "0" toe-in (for minimum tire wear and help maximize fuel economy). To me, these orientations can work for pretty much every car on the road. BTAIM
NOW, with my Camaro set that way, I began to notice "edge wear" on the (stock size) P225/70R-15 Radial TAs, although several sets had no issues getting to 90K miles/set. Not "major" edge wear, but it was there.
From these experiences, adding more caster to a Chrysler front end (for any reason) can result in "edge wear" on wider tires and wheels. Especially wide, lower-profile tires.
With the narrower tread width of tires in the earlier 1950s, when that geometry was designed, the intent was to keep the tire's narrow tread perpendicular to the road surface at all times for increased vehicle cornering capabilities. So, effectively, with much wider tires and greater camber, these "modern" settings can be more self-defeating on a Chrysler front end than on a GM or Ford front end.
In about 1969, "Car Life" magazine did road tests and took pictures of the car's front end in a certain banked turn at 45mph. The Chrysler geometry was on full display, as were those of Ford and GM cars. In one picture of a '69LTD, the tread patch on the Michelin radials were fully 1/2 the rim width inside of the wheel rim's location on the car. That much tire deflection compared to where the tread was on the road.
I have seen the referenced chart before, with the mention of "modern radial tires" in the mix. It was obviously built by someone who might not be fully aware of the Chrysler front end geometry, presuming "they are all the same" (as Ford and GM)? Just MY suspicion . . . In one article with that chart, they also advocate for urethane suspension bushings too.
What is NOT mentioned is TIRE PRESSURE! In the later 1960s, "Car Life" did an article on tire pressure. Related to weight carrying at various inflation pressures. Their road test spec sheets usually had Chrysler B/RB C-bodies at 55/45 weight distribution split, F/R. I used those tire pressure/weight capacity charts to have the F/R tire inflation pressure bias match that actual weight distribution. NOT what the factory recommended, as the factory recommendations had some side issues built int= them.
With base inflation pressure (smoooth ride) being 24psi cold, but "Increase 4psi for 75mph speeds (highway driving), that got to 28psi. That is what I used for the rear tire inflation pressure. From that point, I added 2psi to the front tires' inflation pressure so that each axle had proportionally the same weight capacity as was at the particular ends of the car. With the ultimate orientation that in a full-bore corner, there would be less understeer and no oversteer, but the car would laterally slide. In reality, by design of the chassis, a slight bit of understeer might remain, I suspect.
Having more air in the front, steering response was improved, too. Made the car more fun to drive, from my experiences.
The OTHER real benefit of my weight/tire pressure bias is that all of the tires were "seeing" the same weight (with their weight-appropriate tire pressures). This meant the tire treads "wore flat" on both ends of the car. No center wear from too much air and no edge wear from not enough air. This was more important for bias-ply or bias-belted tires than for radials, but still could happen with radials and their firmer belts. The P-Metric radials (and their "softened" belt angles) can be more like the older bias-belted tires in this respect.
Some might tend to disagree with my findings and experiences, but they are MY experiences and MY proven calculations.
To me, the only changes to my above orientations is that with P-Metric tires, rather than the earlier tires the cars came with when new, just add 2-3psi to the inflation pressures. Like 32/30 rather than 30/28. P-Metric tires were designed to ride smoother at the newer, higher inflation pressures recommended to maximum fuel economy, in the earlier 1980s and later. Which also meant impact harshness was softened a bit by the outer radial belts not being completely perpendicular to the main carcass belts they were applied to. Looking at some of the old Michelin tire cur-away views and current such views can illustrate this.
Thanks for your time and consideration. Sorry for the length.
Have fun!
CBODY67
