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I'm building an Mk4 Roadster using the basic kit and a 1996 donor car. The kit came with halibrand 17 x 9 and 17 x 10.5 rims. I've been told by the FFR tech that the 10.5 rims won't fit my car because the 1996 rear axles are too long. They recommend that I purchase shorter axles, that were for the fox body mustangs, but I'm reluctant to start that project. FFR may be willing to exchange the 10.5 rims for 9". Does anyone know if the 9" rims and tires, when mounted on the stock 96 rear end, will work, or will the tire rub on the fender?
thanks
Joel
 

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9's will work. I went down this road with my '95 rear end when considering to keep my 17"x10.5" wheels. But when I decided to go the the 15" wheels the rear wheel is 9" and I decided against the fox length axles. I kept my longer axles.

The Fox width axles are a total of 3" narrower or 1.5" on each side. If you like the look of the 10.5" or are doing Autocross, most do the conversion. And it wouldn't be that hard.

To do the conversion, you can use the same rear end. But you need to purchase the narrower axles, plus offset brackets for your rear brake calipers to bring those in 1.5" on each side too. If you have ABS ring, it may create a problem, but I'm not sure.

See HERE what you would need to purchase.

Hope this helps.
 

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Another solution is to have the rear axle narrowed including the axles. I had a shop in La Habra CA do this for me. My donor was a 2004 Mach 1, the rear axle needed to be narrowed 1 5/8" on each side to fit the 17x10.5" Halibrand replica wheels. The job should have cost $500, but messed up the first time by the shop. Any way that is a long story. By having the rear axle narrowed, I was able to keep the ABS and install the braking system just as it was in the donor Mustang. In the back of the build manual, FF gives information on the width needed to run the 10.5" wheels. The cars look so much better with the wider wheels in the back, so give having the axle narrowed first before downsizing the rear wheels.

Alan
 

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The Fox width axles are a total of 3" narrower or 1.5" on each side.
Actually no. The '94-'99 rear ends are 1.5" wider in total or .75" per side. '99-'04 are 3" wider total or 1.5" per side. '94-'98 use the same housing as '93 and earlier Mustangs and can be brought to Fox width with shorter axles and caliper relocation brackets. '99 and up can only be brought to Fox width by shortening the housing.

Jeff
 

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Changing out the axles and the brackets is not hard at all . I did a mod on my rear disk brake brackets to bring them in to match the fox width axle .There are vendors that sell the bracket to bring them in like North Racecars Replica and Mustang Parts Connection . There is lots of info about changing out the axles .Much easier than I imagined. Also this way you can keep the deeper look of the rim in the rear.
 

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In some cases, you can get way with 10.5" wheels on a 94-98 width rear end. It takes careful planning and setup. I am running the FFR halibrands with a 95 rear end, 315-35-17 tires and no tire rub.
It is all in the adjustment. You'll need a 3 link setup to make it work. The 3 link setup allows you to center the axle in the wheel well. Actually, you don't want the axle centered at ride height, but centered under compression. The whole axle moves in an arc with the 3rd link as the pivot arm. Ride height is an important consideration as well. Mine is working at 4.5" rear ride height.
Also consider tire width. Even between 315 width tires from the same manufacturer, the width can vary. As an example, the nitto NT555R has a listed section width of 12.13" while the nitto NT01 has a listed section width of 12.48". The summitomo HTR Z is listed at 12.6" wide while have seen other even wider. Between the widest and narrowest 315 tires listed above, there is a 1/4" of difference per side! I happen to be running the NT01, which is not the narrowest tire available, but likely has a more rounded shoulder block compared to a standard summer tire.
When I finished the adjustments on my car, I marked the body and the tire with paint so I could tell if there was rub. In the last 700 miles, I have not seen indication of any tire rub, and that included a track event at Garnett with swoops and dips at high speeds.
Another option would be to run a 275 width tire on the 10.5" wheel. That should give you an extra 1/2" per side. The downside is that the tires will appear streached to fit the 10.5" wheel.
 

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Actually no. The '94-'99 rear ends are 1.5" wider in total or .75" per side. '99-'04 are 3" wider total or 1.5" per side. '94-'98 use the same housing as '93 and earlier Mustangs and can be brought to Fox width with shorter axles and caliper relocation brackets. '99 and up can only be brought to Fox width by shortening the housing.

Jeff
Ditto, easy to do with 94-99 rears, not hard with 99- 04,but more expensive and requires a shop to do the work, Unless you are very crafty>:)
 

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there is actually no need to buy new caliper brackets either. It is very easy to cut them and relocate them on the inside of the axle flange. That is what I did with mine. Simple.
 

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I purchased an incomplete kit where all the parts were supplied... in pieces. I've assembled the axle assuming it was the right one. I just installed the body and the wheels/tires are too wide. They are 295s on 15" halibrands. They look to be 1+" too wide on each side. How do I know what I have and what I need to fix to the correct width? Does anyone have the width measurements?

Edit: current measurements are;
housing width, 56-1/4"
Axle width 61-3/4 to the face of the axles.
 

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For the record, Richard Oben is pretty awesome. I called him and he had my parts shipped within 20 minutes. They're installed and look great. I have a trickflow diff cover that has problems though. this particular cover has bearing cap support bolts. They split out before I reached 10 lbs of torque. new bolts coming but the delays are frustrating.
Thanks for the information and letting me hi-jack this thread.
 
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