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Discussion Starter #1
So a couple of questions about wheel sizes and back spacing, if you don't mind..

My 66, which I bought last year as it sits now, has 16x7 wheels with 4" BS on all 4 corners. The PO originally put 225/55R16 tires on the rear, but he felt the car needed better traction and mounted 245/50R16 drag radials on the rear. Besides the better traction, they add to the look which I love. However I do experience slight rubbing when I hit a harsher bump, especially when I have a passenger. Looking at the fenders its seems to just be rubbing just behind top dead center of the fender, and it seems only about 1'4" deep from the inside edge.

I'm thinking new rear rims with a 4.5" back spacing should almost stop the rubbing. Looking like I have over an inch of clearance between the tire and springs. What am I missing with this thinking?

Also, what, if any, advantage is there of going to an 8" wide wheel? What does a wider wheel do? I'm happy with the size of the tires in the back and not looking to go any larger. I'm also not adverse to rolling the fenders, besides the fear of doing any damage to the paint or fenders.

Thanks for any knowledge you share!

 

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Nice car.????
You may be able to increase your backspacing.
On 65-66 you have to be mindful of the area in front of rear tires above the springs.
Basically the side of the rear seats.
It curves towards the front edge of the tires.

Just for reference, I had BFGs 235/60/14 with same issues but my wheel was 14x6.5 with only 4” backspacing...4.25-4.5 BS would have been better.

Currently have 18x7.5 (with 1” spacer) 4.75 BS with Pirelli P Zero Nero A/S 235/40/18...(they run narrow about 9” vice 9.25”) front and rear. This setup has no fender issues with my suspension.

I have 5 leaf mid eye springs and KYB Gas A Just.
Front is 620#, Arning/Shelby 1” drop.
 

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If you go to an 8" wide wheel you will need at least a 4.75" backspace and closer to 5" would be better. If you stay with the 7" wide wheel 4.25" backspace will help and 4.5" backspace will give you plenty of room.
 

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Wheel and Tyre Combinations for Classic Mustangs.
What tyres will fit?
65-66 Mustang Wheel /Tyre Fitment
Wheel SizeCorrect Backspace Suggested Tyre Sizes
14 x 64.0 inchP215/70R14
14 x 74.25 inchP225/60R14
14 x 84.5 inch *P225/60R14 to
P235/60R14
15 x 64.0 inchP215/70R15
15 x 74.25 inchP225/60R15
15 x 84.5 inch *P225/60R15 to
P235/60R15
16 x 74.25 inchP205/55R16 to
P225/60R16
16 x 84.5 inch *P225/50R16
17 x 74.25 inchP205/50ZR17
17 x 84.5 inchP235/45ZR17
18 x 74.25 inchP225/40ZR18
18 x 84.5 inch *P245/40ZR18 to
P265/35ZR18
* Rear fitment only
67-70 Mustang Wheel /Tyre Fitment
Wheel SizeCorrect Backspace Suggested Tyre Sizes
14 x 64.0 inchP215/70R14
14 x 74.25 inchP225/60R14
14 x 84.5 inchP225/60R14 to
P245/60R14
15 x 64.0 inchP215/70R15
15 x 74.25 inchP225/60R15
15 x 84.5 inchP225/60R15
15 x 95.5 inch *P235/60R15
16 x 74.25 inchP205/55R16 to
P225/60R16
16 x 84.5 inchP225/50R16 to
P245/50R16
17 x 74.25 inchP205/50ZR17
17 x 84.5 inchP235/45ZR17 to
P245/45ZR17
17 x 95.5 inch *P245/40ZR17 to
P275/40ZR17
18 x 74.25 inchP225/40ZR18
18 x 84.5 inchP245/40ZR18 to
P265/35ZR18
18 x 95.5 inch *P245/40ZR18 to
P265/35ZR18
*69 and 70 models only.
Source: Rick Ciemeny from Halibrand Engineering


 
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Discussion Starter #5
Thanks for the information..seems there’s no advantage of going to an 8” wide rim besides the look and taking some of the bulge out of it.. I’m not auto crossing or anything.. and increasing the back spacing with the 7” will help with tire rub, which is what I’m looking for.
 
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