wandering car after ford 17x9 cobra r wheel install

i coverted my 88 to sn-95 brakes using parts from a 95.i had the car aligned right away to fox specs and had 95 gt 16" wheels on there.car drove perfectly,straight and true.then i put on real ford cobra r wheels 17x9 with 255/40r17 tires and car wanders all over the place.they were used tires,so i bought some new ones like my alignment guy said.car still wanders all over the place.doesent pull in any one certain direction.it just pulls with every dip,or even the slightest irregularity in the road.should i get it aligned to 95 mustang specs?or is there a certain degree of caster,camber,or toe that will help?there has to be something i can do,car is very scary switching lanes on interstate.please help!
 
I had the same problem with my 87 before I got rid of it. I thought a lot of the problem was the 15 yr old suspension, which I'm sure it was! I'm sure there are many other things that help with this wandering though! Maybe someone could give us a more in depth answer?

Jakob
 
Sounds to me like bump steer. My '92 does the same thing, with stock Pony's and my r58 Cobra R's. It is annoying as hell. Look into a Baer bumpsteer kit. When you get it fixed, the brake , wheel, and tire upgrade will be well worth it.
 
bumpsteer was the first thing i thought,but the thing me and the alignment guy cant understand is that car was fine after 5-lug conversion with same width tires in the front.im thinking it has something to do with wheel offset?maybe changing alignment angles?oh,btw,i have a steeda bumpsteer kit.thanks.
 
When I purchased a new set of Firestone Firehawks, I wasn't aware that you can pump those babies all the way up to 44psi! I was running 33'ish or so, and the Fox Body wander was worse than ever.

After pumpin them up to 40-42, the ride is much straighter.

Anyway, the quality of your tire has a lot to do with handling characteristics on a Stang (or any car for that matter).

Just my 2 cents.
:shrug:
-B-
 
it could be that the tire is a smaller profile with a stiffer sidewall that doesnt give as much when the tire is in a rut in the road. my camaro used to do that really bad with 17 inch tires. sometimes if the turn was just right you wouldnt even have to turn the wheel because the tires would follow the line of the road.
 
You will probably need a custom alignment here.

The 17 in wheels and tires are wider and flatter, with squarer corners than the oem 16s. The tire is therefore more sensitive to the road than previously. And wanders.

I went through this when I went from TRX's to 225-60-15's and again when I lowered the car. First couple alignments left it with no real interest in going straight by itself. But it spec'd out ok.

A different alignment, after the addition of caster plates, fixed it.
 
mine wanders with my 17's only 15 and 16's were fine..

Bullit69 .. that is a MAX tire pressure. if you inflate to 44 you are overinflating your tires which will lead to wearing out the center of the tread and a blowout. Optimal pressure for those tires and most 17's are 30-35 MAX! the reason it probably helped is you essentually made your tire narrower by overinflating and riding on the center
 
BowTieK,

Yes, I would imagine 44psi a bit cheeky, and you're probably right.

I leave the rear rubber at 35, front around 40ish.

Either way, it does help. The tires don't look overflated, i.e. if you look at them from the side, they still have that slight "lip" protruding where they make contact with the road.

I've never seen tires stamped with 44 as the max inflation, all others I've owned say 35. Thus my assuming they take a higher pressure. :shrug:

In any event, I will look into it. Thanks!
 
i already have a steeda bumpsteer kit.car was aligned to stock fox specs.tires,have tried 3 so far,1st was a old set of goodyears that were on the front of corvette for about 20k,figured those tires were junk.2nd set was 1k mile old bfg 275/40 g-force ta,problem the same,3rd set i went and bought new 255/40r17 kumhos.prob is a little better,but still too bad to me.i think my problem is tramlining.i think a custon align is the key,but me nor the alignment man is shure on exact specs.should i have him align to 95 specs?are 95 specs the same?or totally custom?if custom,does anyone know good specs?
 
wider tires do that, my camaro almost gets stuck in grooves in the road. (yes I have a camaro, I am hear because my dad and I are rebuilding a 93 gt. But I must say right now my lt1 rapes it)
 
Adjust your bumpsteer and get the total toe set to .10* inward. Also, what are your caster and camber readings. Excessive negative camber (top of tire in) can contribute to the wheel being more sensitive but caster has a big effect on the directional stability of the wheel, or in English that's the tendancy for the wheels to stay in the same direction. More caster will help keep the wheel straight.
 
OKay my suriousity is peaked. I have the same problem and thought that maybe something else in my frontend was bad. I almost went out and spent a fortune for new control arms, balljoints, etc. Glad I found this thread first.

Where can I get a custom alignment? I don't think Firestone or chain stores do them, or do they?
 
ok, I recently replaced my tires and all four of the are 245x45x17, got a good deal on them, anyway when I took the car for alignment the guy aligned the car to a 94 or 95 stang who run 245's all around. I own a '89 and if they align the car to the '89 specs it will not work correctly cuz the tires back then were only 225's and make sure where ever you take the car make sure they can align camber plates. I hope this helps and good luck
 
im going to get car aligned tommorrow at my dealership.he had just aligned a 2000 gt and the camber spec was -6 degrees,toe was about 0,and caster was only like .14.im going to have him set -6 camber,.10 toe in,and +6 degrees caster.ill let everyone know how it turns out tommorrow night.my alignment guy seemed to agree with those settings,except the -6 camber.hes going to do what i tell him though.