89 stand 5 lug Question

[89stang351W]

I have a 1989 MUstang GT Hatchback that I converted to a 5 lug thinking I would have more options for rims. I am ready to buy tires and no one can tell me what size will fit on this car so the front does not rub when turning. I have a 351W under the hood so it is sitting a little lower then stock. I also used 1994 Cobra parts to make the conversion to the 5 lug.

Does anyone have or know someone who had made this switch and can tell me the right tire and rim sizes so I don't rub?

I have an extra set of tires that I borrowed from a friend. The rear tires are currently 17x7.5 255/40 (with no off set). This works great for the rear; however, the front tire size (17x7.5 235/40) leaves very little space between the front tires and the fenders. I can barely get my fingers between the two. I visted my local tire store and they said, "we would just be guessing".

Can anyone help me out with this one? I am dying to put some new shoes on my baby!
:banana: (I use that because I like it)

 

[Yellow4.6]

I just put 255/40/17's on the front of mine and 275/40/17 on the rear. With 17x9 FR's on all 4. No rubbing, did remove the quad shocks.

I wouldn't go any wider than 255 in the front, prob could've gone 285 in rear with no problems.

 

[wheelhopper]

I have 255/40/17's mounted on '01 Cobra wheels, on the front. I don't think that I could go wider the way I drive my car. I drive it on the road course. The backspacing on all the Mustang wheels from '94-'04 will work. So you could use

Mach 1 wheels
'94-'01 Cobra wheels
Bullit style wheels
Any GT Mustang wheel from '94-'04

 

[89stang351W]

I currently have 17's on the front that are 235/40 but I can barely get my fingers in between the tire and the fender so I know when I am out on the road the front end will bounce and the tire will hit the wheel well. There is no way that the 255 will work.

I am shocked that this is so difficult for me to find the right size rim.

I guess I should go with 16's and use 235/40 just to be safe. Anyone agree?

 

[wheelhopper]

It sounds like to me that your issue is your backspacing. What brand of wheel are you using. I run '01 Cobra rims, 17x8, with 255/40s on the street and on the road course use '95 Cobra rims, 17x8, with 245/45s. I have not had any tire rub in any scenario. I can assure you that If I am not getting tire rub with these sizes on track that you won't on the street. If you want a wider tire I think you are going to need a different wheel.

 

[89stang351W]

The wheel that I am currently using is an American Racing wheel. It has an off set of zero (according to Discount Tire guy). He suggested that I go with a positive off set of like 6 or 12.

If I am reading the tire size corretly the 235 is the height of the tire. So regardless of the off set, a 255 would be even taller and still hit the under side of the fender.

Sorry to be such a pain but damn I want this thing on the road!:coolman:

 

[WhiteLX50]

94-04 17x8 OEM Mustang wheels are usually ET30 (or +30mm offset). Compared to a 0 offset, the wheel will move in towards the center of the car. 0 offset is definitely not correct for a Mustang, so it's no wonder you have clearance issues. The most you can go is around 17-20mm offset, but that's usually for narrower wheels, like a 16x7.

A 17x8 with a 22-30mm offset should work well.

A 235/40R17 would be a lower profile than a 255/40R17.
Example, 235/40R17:
235 is the width of the tire in mm, sidewall to sidewall (also known as section width)
40 is the aspect ratio. What this means is the sidewall height is 40% of the width of the tire.
17 is the wheel diameter, but I'm sure you knew that.

Using simple math we can figure out the overall height (diameter) of the tire.
[(235x.40)x2]/25.4 + 17 = 24.40" diameter

25.4 is the conversion from mm to in
multiply times 2 because you have to account for the sidewall twice in an overall height calculation.



How low is your car? I'm guessing it's pretty damn low if you're having issues with a 235/40R17. That's a small diameter tire. IMO, too small for a Mustang.

 

[89stang351W]

To WhiteLX50:

I appreciate your input, sounds like you know this stuff MUCH better then I do:-D. I think that you gave me great information to make a decision.

I am not sure exactly how low it is sitting to the ground but it is lower then stock with the additional weight of the 351 in there.

Thanks again.
:beer:

 

[Mustanganatic]

I'm going to be switching over to 5-lug this week. I'm using '94 spindles. The wheels will be 17" x 9" '95 R wheels with 255/40s. I've got a Saleen ground effects kit on it and the front bumper cover wraps around the wheel well at the bottom. Hoping I don't have an issue with tire rub because of that. My question is that I'm also thinking of lowering springs. I'm looking at the Eibach Pro-Kit, part no. 3510.140 and the H&R Sport Spring, part no. 51650. They're a moderate lowering, 1.2" in the front. Anyone got an opinion on either spring and if I'll have a rub issue? wheelhopper, I'm guessing your's is lowered, but I'll be using a 9" wheel. If my calculations are correct, my wheel will only be sticking out 3.7mm more since the 9" has a +24mm ofst and the 8" +15mm.

 

[Mystic-SVT]

When I did the 5 lug conv on my old 91Gt I used '95 spindles and '95 balljoints. My front wheels were 18x9 bullitts with a 245/40/18 tire. It looked like the tires would rub the fenders when the suspension would compress but I had my buddy drive the car for me and I was next to him as he drove and when the tires went up and down they didn't hit the fenders at all. The tire doesn't go straight up, its goes up at an angle toward the center of the car so you should be fine with a 245 and maybe even a 255. Just make sure you don't get too tall of a tire

 

[Mustanganatic]

Thanks Mystic. I'm putting on 255/40s. The fenders on the '91 are a little wider than mine though. I can't remember what year it was they changed, but the fenders on the latter years of the Fox's were a bit wider than the early ones.

 

[Mystic-SVT]

I forgot about the fenders; I think they changed in '90. I think the actual opening was increased longways if im not mistaken, but I might be wrong.

 

[wheelhopper]

The fender change you are refering to started in '91. The fenders were'nt wider, the wheel opening was made wider by making a slight change in the design of the front skirt. This was done to help accomodate the change in tire size from the 225/60/15 to the 225/55/16 that were on the Pony style rims.

Looking at the room that I have with the 255s, mounted on an 8" rim, I doubt that I could fit a 9" rim with a 255 or 275 on the front. I could not do it on the rear either, because of the IRS. If your running a straight axle you'll have a little more room to work with and 275s should fit no problem.

I do have a friend that has 275s at all corners, mounted on '03 Cobra wheels. He says they fit no problem, but the car has hardly been driven since he did the conversion.

 

[Mustanganatic]

Looking at the room that I have with the 255s, mounted on an 8" rim, I doubt that I could fit a 9" rim with a 255 or 275 on the front. I could not do it on the rear either, because of the IRS. If your running a straight axle you'll have a little more room to work with and 275s should fit no problem.

I do have a friend that has 275s at all corners, mounted on '03 Cobra wheels. He says they fit no problem, but the car has hardly been driven since he did the conversion.

Well, if the 255/40s aren't going to work, I got a set of 245/45 Gatorbacks. If my calculations are correct, the 255/40s on a 9" wheel will only be 3.7mm more on the outside. The 9" has 9mm more of offset. To add a fly in the ointment, I'm lowering the car from stock with H&R Sport springs. That'll be 1.2" in the front. I'll let you guys know how it turns out, but it might be a while. I'm having a problem getting the H&R springs in a timely manner from the Tire Rack. Also, I got to figure out how to cut down the spindles so that the center caps will fit. I'm thinking of just grinding it down.

 

[Mustanganatic]

I'm sending back the 255/40s and going with 235/45s in the front and 275/40s in the rear. A buddy of mine has a '93 has that combination, but in 18s. He said the 255s were rubbing. I ended up canceling the H&R springs order from the Tire Rack and ordered them from Mustangs Unlimited. Hopefully, I'll get them sooner there. I'll post some pictures when I get it done... whenever that may be!

 

[wheelhopper]

I had the H&R Super Sports. They were great springs, except they lowered the car a lot. I think it lowers the car 1.7'. I had the stock 225/60/15s on at the time. I doubt that I could have gone much wider. Currently I am using the H&R race springs for an '03 Cobra. The car sits lower than I thought it would, and is definitely stiffly sprung, but I have no clearance issues.

 

[Mustanganatic]

I'm putting on the H&R Sport springs. They lower the front by 1.2" and they're a progressive spring so the ride will still be half way decent.