thejollypostman

I had the Nitto 555s 315/35 on my 00' GT with 17x10.5 fat *** wheels.

Put a 99' cobra rear end into the GT. Brakes lines fit. ebrake cables fit.. gonna need a new pipe for the catback. but...

The 10.5 wide wheels do not fit and hit the subframe. the tires are popped anyway so looking what to get.

Questions:
1. Do the wheels need to be the same size for the front and rear for an IRS setup?
2. I have 17x9s up front so i could get the same for the rear similar to a cobra, however, i would rather be staggered.
3. Whats the widest wheel people have had in the rear for a cobra?

theres gotta be a bunch of thread/commments on this somewhere so id welcome any links as well thanks

thejollypostman

I guess the backspacing/offset of the wheels is too great?

thejollypostman

from american muscle .com

Why can’t I put a 17x10.5” rim on the rear of my 99+ Cobra?
The 99+ Cobras have an Independent Rear Suspension (IRS). Using a larger wheel means that the tire’s sidewall will rub the rear IRS subframe-mounting bolt.
However, by changing out the stock .5” factory IRS subframe bolt with a shorter one, you can use 17x10.5” rims.


It hits more than just the subframe bolt.

school boy

I had to run spacers with my irs and 315's.

AMDanBailer

Hey,

Sounds like an awesome set up your going to have here shortly!

As mentioned before, it seems like you will need a some sort of spacer. I imagine you will want to still have the low profile bolts, but if you are still hitting the subframe itself, you will certainly need some kind of spacer to say the least.

You can run the 9" wide wheels all the way around if you wish or you can keep the staggered set up, it is mostly personal preference. If you are already hitting the subframe with a 315, I really wouldn't recommend putting any larger tires on. I have seen 325s on the back of actual cobras, but that is pushing it.

I hope this information helps and if you have any questions feel free to get back in touch. Good luck!

-Dan

thejollypostman

Where did you get them from. What sizes are available.

school boy

I have longer wheel studs so I just ran what I needed which was a 1/4". Im thinking the narrowest bolt on spacer is either 25mm or 20mm. If you run a spacer, deffinently run hubcentric spacers reguardless.

thejollypostman

They make hubcentric spacers that are that thin?

AM's smallest spacers are 3/16 and they are not hubcentric i think its what i need. suppsedly the stock studs and lugnuts work with them too

According to a few sites fitment charts my wheels....

http://www.americanmuscle.com/blk-dd-cobra-17x105.html

doo fit the 99 cobra you just need the low profile irs bolts. but theres some serious rubbing.


for those wheels offset is +27 mm , backspacing is 173 mm.

stock specs for 1999-2004 mustang, mustang gt & cobra
factory wheel sizing: 15-17"
factory bolt pattern 5'x114.3 mm
stud sizing 1/2"x20mm
center bore 70.3
offset 35-50 mm (H)
max wheel size 22 inches

this chart is for 9" wide wheels i believe

Are there other 10.5 inch wide wheels out there i could have bought that have a slightly less positive offset? (meaning the bolting surface is closer towards the brake side and that the wheels sticks out towards the road side a little more)

also do you think its possible the spacers throw off the balance?

school boy

You would have to check on the other wheel, im sure there are but don't know off the top of my head. I was thinking MM made hubcentric spacers that thin but after looking, they don't. I also didn't realize you didn't have the low profile bolts, these will help but may not totally fix the problem. At least they didn't for me. As for the balancing, they wont hurt anything. Til I installed longer studs, I ran cheap spacers from a parts store. I don't recommend them but I didn't have problems out of them for the 100 miles I used them.