Widest 15” wheels and tires.

[69dearborn]

Hello,
I’m doing a lengthy front to back refresh on my ‘69 R code sportsroof. I have decided to go to 15” Magnum 500’s and need to determine if a 15”x 10”with 5.5”backspace mounting P275/60/R15 tires will fit into the rear opening without modification. Currently the car has 17” x 9” with 4.5” backspace mounting P275/40/R17 tires on the rear. Can any of you ‘69 - ‘70 enthusiasts tell me the widest rear 15” wheel/tire you have stuffed under your sportsroof without cutting or reshaping the metal?

 

[B67FSTB]

Although I haven't a 69 , how much space do you haven right now , between tire / leafspring and tire / wheelwell ?
275 on a 10 inch rim , it will make some "cheeks". IMHO.

 

[Mach1 Driver]

I have pages of notes on wheel and tire sizes for 69s, and as you would expect, they vary greatly.
The usual answer to that question is 15x7 wheels with 4.25 backspace and P235/60R15 is the largest wheel/tire to safely fit in the front, and also works in the rear.
For the rear- on 69/70 only:
15x8 245/60/15 (no mention of backspace)
15x8 4.5 backspace P225/60R15
15x9 5.5 backspace P235/60R15
15x10 5.5 backspace P275/60R15

Good luck