handling help needed

[Mike DC]

JR - Yes I have some trouble with my steering wheel coming back to center. It usually doesn't want to

People normally assume this is related to the steering box but it's really the caster alignment that needs to change.  The factory designed these cars with 0 degrees of caster to make it easier to park cars with manual steering.  More degrees of caster equals more natural tendency to re-center itself when you let go of the steering wheel.  (Think about a bicycle - give it a shove & let go . . . the more the front fork angles back, the more the bike naturally tries to roll straight.)

Rick Ehrenberg (Mopar Action magazine) once wrote that he didn't think you should push these cars much over 3-4 degrees of caster.  Some modern vehicles have more but they also have different geometries in other ways.

[c00nhunterjoe]

The problem with going much over 4 or 5 degrees is the ball joint angles, specifically the lower. It will have it nearly in a bind as you increase caster. A custom set of arms would be needed to properly center the ball joints for normal street use if you wanted much more. But just going from 0 to 4 degrees alone is like having a new car.

[fizz]

With my tubular upper control arms I couldn't get past 4 degrees caster anyway, but still huge difference.

[myk]

Does that mean that my 6.5* of positive caster might cause problems later?  I'm running the Hotchkis UCA's...

[fizz]

I wouldn't think so myk, if it works it works. Put 6 degrees on a straight axle project hot rod and works good. For some reason, the wheel alignment shop who did my charger couldn't get more than 4.

[myk]

I wouldn't think so myk, if it works it works. Put 6 degrees on a straight axle project hot rod and works good. For some reason, the wheel alignment shop who did my charger couldn't get more than 4.

That makes no sense.  All that geometry and numbers and science down there lol...

[redgum78]

Adjustable upper control arms would be my first addition. The extra caster makes a big difference.

[HPP]

In ideal circumstances, you want .5-1* more caster than that Spindle Axis Inclination. Since the old mopar disc spindle has 6-6.5* SAI, this would translate to 7-8* of positive caster in an old mopar. This creates the greatest amount of tire contact through suspension articulation and body roll,  but as pointed out by MikeDc and coonhunterjoe, there are other factors to consider as well if you are pursuing ultimate as opposed to adequate.  For the vast majority of us, getting 3-4* positive caster is world changing in these cars.

Again, you never quoted us a budget or timeline so we are swagging things here. Tubular arms are great but pricey. Offset bushings are inexpensive, but don't provide as great a range. $300 spent on tube arms, compared to $30 spent on bushings, may defer your budget from other important items. If cost is inmaterial, then just keep adding parts to these lists and do it. Heck, to save headaches, just order up a Hotchkis TVS package and put it on.

[poppa]

The budget keeps getting smaller and smaller.

Would a 245 tire fit on the same rim as my 205?

Ran across this , looked kinda cool.  https://www.youtube.com/watch?v=xrsEfWtrShM

May try the 245's ,and adjusting caster/camber if I can find the tool for a good price. Otherwise I'll take it in when I can. What should I shoot for then , 4* caster seems like the magic number. What would camber need to be , I'm sure when I had it done they went by the book.

[HPP]

Ask them to try and hit '05 Mustang GT specs so they have something to look up in their computer. They wont be able to hit these, but it is a compromise to get some thing they can pull up on their system to shoot for.

This translates to as much positive caster as possible. Realistically, this will probably be no more than 4-5* positive. You want some negative camber, -.5 to 1*. Toe in should be .1* or around 1/16". Positive toe is toe in, negative is toe out. Unless you are racing, you don't want toe out.

What width is your current wheel? 205 recommended width is 5-7". 245 recommended width is 6-8" If you have a 6" wide rim, you can squeeze a 245 on there and maintain decent pressure. If you use a narrower rim, then you risk crowning the tread at regular pressures. To get full tread contact you would have to run lower pressure which then makes for softer sidewalls, which is a bit counter productive to improving handling.

[Mike DC]

   
Wider rims (for a given tread width) are a good idea if you can afford it at some later date. 

The low-rider crowd takes it to a stupid extreme but you can see the principle here.  There's no way this tread can move very much laterally during cornering:

[poppa]

This car hates me. It just gets worse and worse. Put in my new leaf springs and as soon as it was on the floor I was like ,this is lower now. Yep , rear still rubs when I hit a bump , even more now I think. I'll start a new thread for this problem as I have some questions.

While letting my car down ( had all four corners up so I could pull my fuel sender to figure out why my gauge doesn't work correctly , didn't do after I recalculated and figured I had too much gas left ,19 gallon tank ,right?) , I noticed my drivers side front tire has almost no tread left on the inside of the tire. So I guess I'll start with new tires and an alignment and work my way up to a bigger sway bar ,torsion bars and maybe a Firm Feel steering box. Seeing as I am going for better handling ,what are some better choices for tires? Thanks and Happy Fathers day to all...

[garner7555]

If you have the cash to upgrade those parts before alignment then it would save you some money because the car will need an alignment after changing torsion bars or the steering box.       You could however add the sway bar without needing another alignment.    PST has some 1.03' torsion bars for little over $200 (fairly reasonable), unless you want to go bigger (bigger = stiffer).       
That is a good list of upgrades in my opinion.       
As far as tires go it really depends on your budget.   I have heard that you can't beat Michelin Pilot Super Sports or Pilot Sports, but they aren't exactly cheap.       Nitto also makes a good option.

[HPP]

Since you mentioned Goodyear Eagle STs earlier, I'll assume you have 15" rims. Don't  know how wide you rim is if you are consider a 235/245 size. Combined with those two parameters, best tire you can get will likely be a Mickey Thompson SR, 26x8x15.