I remember asking how large a tire you can fit under a stock 1968-1970 (mine is a 1969) B-Body and had some great responses. People chimed in with various tire sizes vs back spacing on different wheel diameters. I searched both the archived threads and all the threads and couldn't find the threads that contained the information.

I am thinking of running 15" wheels on the front and back of my Roadrunner and I am looking at buying new wheels...possibly Rocket Injectors all around or with Rocket Launchers in the front. They are only 15" x 4.5" so I wouldn't have the big rubber forward for stopping, but they look cool. What size wheels and tires can you fit under the back of a '69 Roadrunner? I have 15" x 8" slot mags with 285/60/15 Cooper Cobras on there now and they rub on the inner wheel well if you romp on it and tip the car.

I am looking at upgrading my front suspension to stop better (disk brakes) and possibly more. I might buy 15" x 8" US Slot Mags and try to put more rubber up front. What size tires should I put under the front?

What back spacing would be best front and back depending on the size? What do you have and how do you like it?

Here is one.

https://board.moparts.org/ubbthreads/ubbthreads.php/ubb/showflat/Number/5725604/site_id/1

I know 275/60-15 fit fine as I gave a friend with a 68 Coronet a used set of tires that size for the rear of his car about a year or so ago.

If you have wheels and tires on the car now you can get a large piece of paper draw up a 1:1 scale cross section of the existing tire, rim width and backspacing, distance from the fenders, etc. as a starting point. Once that is done draw up the other combos your looking at using the same 1:1 scale and overlay them over top of each other on a light table or taped to a window in your house and you can see what different backspacing, tire widths, and diameters to what you have on the car now.

I have done this overlay trick many times using autocad to test out wheel and tire sizes for myself and others.

Good idea! I think 4" is standard on the US Slot Mags. Will that work on the front? I have 14" wheels on the front now and I want to upgrade to 15" wheels.

Edit: I have found a lot of great options! I'm curious what the largest width you could fit on the front without rubbing. I see a lot of 15x6 front wheels advertised, can you put a wider low profile tire on the front?