track question,, when is it time to run skinnies vs wider wheels??

[ruger311]

currently i have 17x9 03 cobras on my 89 gt vert w/ sn95 spindles 13" cobra brake setup, last year i had bilsteins shocks/struts with 250# spring rate up front upr coil overs, launching at ~6-8# when i shifted into 3rd and 4th the ass end would get a lil loose mid track, get outta it and get back in it, managed 11.1 @ 123mph with it, car is 347 t-76 hp kit at 11# making 600RWHP AND 611RWTQ @ 3200 rpm

since then i have swapped to a 175# spring rate up front and strange adjustables all around, airbag in rear right coil,

since i have the cobra brakes have to run a 1 1/16" or so spacer to clear the calipers, this makes my prostar 15x3.5" with 1.75" bs stick out from the fender ~1/4-1/2", just wondering if i am going to come down hard enough to hit the tire and cut it up on the track???

will me running skinnies up front help out with the ass swaying around any down the track??

some people have said that pushing a 9" wheel up front is not only dangerous but makes the car unstable?? ive been 126mph on DRs and didnt see that just on the slicks at 11#s in each tire

any reason for safety that i should be running the skinnies??

the other option to not run a big spacer is to swap back to fox spindles and buy some aerospace pro street kit (still a street car) but some say that they still have to run a 1/2" spacer and sticks out a lil bit

i know i will reduce at least another 100#s up front if i swap brakes and skinnies which is a plus

trying to make the correct decision here and for the future of the car which should run 9s or high 8s with more boost/fuel

thanks in advance

[Gen1SVE]

I put larger tires and wheels up front of my fox to make it more stable and it did help.  Look into the wheels the supra guys use for skinnys that clear the big brakes.  I talked to the guy and he has wheels sitting there for the Fox cars who want skinnies and run big brakes.

Here is a vid of my fox with big tires/wheels in front making a pass.  It has always been straight as an arrow with this tire/ wheel combination, but a lighter combination would be nice.

http://videos.streetfire.net/video/Mikes-turbo-mustang-cecil_203019.htm

[Unatural]

I was having the exact same thing happen with my car when I was running slicks with my big street tires in the front. After I put the skinnies on the front, it made it totally stable. My car runs 127 mph.

I was diehard about keeping my Cobra brakes, but having the skinnies in the front too. What I ended up doing was buying a set of A arms that are 1" shorter than stock. Then I had my front wheels narrowed 1" so I wouldn't have any clearance issues on the inside. I have Bogarts that have the spacer welded on to clear the Cobra brakes, and now they tuck up under the car just like any other skinny tire does on a Mustang. Here are some pictures of everything. The first picture is with the stock length arms on it and the second one is with the shorter arms. The 4th one is with the narrowed Cobra wheels on the shorter arms.

[ruger311]

cool deal i remember you posting this up before,

think i am going to go back to fox spindles get an aerospace floating kit and then my welds will fit with 1/2 spacer, this will bring my wheels back in 1" from where they are now, shouldnt have any problem with that

[Turbo_Baer]

i need to purchase some tires this week, but i just fitted my new 15x3.5 with 1.75bs greg welds on with a 3/4" spacer and it seems to clear the cobra caliper. looking down on the fender, the rim is flush with the fender. this is with and unloaded suspension up front. i think the wheel will tuck in nice when i get tires. ill post some pics up soon. 1 piece spacer should be here tuesday.

[Saul]

I hate to hi-jack the thread but I have a few questions about things said here:


Where is everyone ordering wheel spacers from? Does it matter if they are cast or billet?

What size a-arms are people running when using a "shorter a-arm"? Stock fox is like 13" right? So maybe a 12"? Does this effect alignment geometry or can it be re-aligned?


thanks in advanced for any help.

[Unatural]

I hate to hi-jack the thread but I have a few questions about things said here:

Where is everyone ordering wheel spacers from? Does it matter if they are cast or billet?

What size a-arms are people running when using a "shorter a-arm"? Stock fox is like 13" right? So maybe a 12"? Does this effect alignment geometry or can it be re-aligned?


thanks in advanced for any help.

The spacers on my wheels were welded onto them. I put a picture of them below.

Yes, the A arms that I have are 12" and yes, it affects the alignment settings. In order to get the alignment right, along with my caster/camber plates, I had to put camber adjustment bolts in it. These are the ones that I bought. http://www.jegs.com/i/Specialty+Products/827/81280/11051/-1#

[Daniboy1983]

How can a wider wheels make it more unstable? this doesn't make sense to me.

[ruger311]

i found out it isnt the wider wheels so much as that the type of rubber being pushed down the track, also my road race suspension didnt help

two weeks ago the car went 11.1 @ 131 with shitty 1.789 60',, last year was cutting 1.50s,, last weekend cut some 1.58s but was cutting out mid track only pushed 12s,,, the 131mph pass i had no ass end swaying this is after swapping to strange adjs and airbags in the rear,, got new brakes this week so skinnies and lightweight front should help out some more too