245/60/15's on 15X8 rims

Is the car small bolt pattern or large? If large, with re-drilled axles or large bolt axles.

A 235/60/15 should work safely with correct backspace and rim width.

235/60/15
15x7
4.25 backspacing

Do not run less backspacing. If you need to make fine adjustments, you can add 1/8”, 3/16”, or 1/4” spacers.

I have 245/60/15 15x7 4.25 bksp in my 68 Dart GT and it is very tight