Tire size for this rim

[john108]

'68 charger R/T: For a 15 x 8 1/2 rim with a 3 1/2 inch back space:  What range of tire sizes can you run before you worry about the 3 1/2 inch back space clearance or outer clearance?  What clearances would expect and desire?
Thank you.

[Long Island RT]

I have that exact rim size on my car.  275/60-15 fit perfectly.  You can probably go as high as 295 but it would have to be at least a 60 series or higher (and those are hard to find).  You don't have to worry about inside clearance you'll have almost 2 inches - but if you sit the car low - you'll have less than an inch between the tire and and wheel opening lip.

[john108]

Thank you Long Island RT
Does your answer apply to the front as well as back wheels?
P.S. I lived on Long Island (Bethpage) many years ago.

[Long Island RT]

Front is a whole other story. 
I have 15x7 with 3½ backspacing in the front and 235/60 tires.  No issues at all. 
If you put those 8½ rims in the front - you may have a fender rub issue on turns and bumps - also depending on how low the car sits.  That's a lot of rim "frontspacing" for the front.  I've seen on this site some folks run 8 even 9" wide rims in the front but I think for that, backspacing needs to be centered - or close to 0 offset.  They also have lower profile tires on 17 and 18" rims - so overall tire width is less than a similar tread width tire in a higher series.

I am eventually upgrading to Centerline 18x9½ in the back and 17x8 in the front with 295/45's and 255/50's Nitto's respectively.  I just need to save some more dough!

Good luck

[john108]

Thanks again.
The reason I asked is that someone was selling 4 American rims from the 60's to 70's vintage. 
The kind that I would have liked to have when I first bought the car in '68.