Widest tire on a 15x7 rim?

yes, but running around on squishy tires isn't the right option either. For me, Weld Draglites don't come in the backspace I need to make 15x8's fit, so it was a compromise I made.
For the record, once it was clear I was wearing the tires I did drop the psi, but that starts to cause issues with your sidewalls that are already bulging over the side of the rims in the first place.

not talking 12psi here. 28-30 psi for my BFG drag radials. my car isn't a handling demon to
begin with, and the lower psi cushions the potholes lol. some other tire brands
with multi layer sidewalls will handle the lower psi no problem. and i highly doubt that
anything over 20psi you'll get the sidewall folding over.

I run a 275/60/15 tire on a 7" wide rim. It works OK, but the tire has a slight bulge look. I run 'em at about 32 psi. Seems to work OK that way. However, I'm switching to a new style wheel that will be an 8" wide wheel on the back with the same tire.

These are 30 x 9 Hoosier radial slicks on a 15 x 7 wheel. They fit pretty good and work fine as I just pulled a new best 60 ft of 1.57 on them Saturday night. Ron

ah shoot, ive run 295/50-15's on em

I run 275/60/15 on 7" wide rims. Been doing this for 6 years and nothing but normal wear on the tires.

I run 275/60's on a 15x7 cop wheel and they're fine, but I wouldn't run any wider in a 60 series or lower. The taller the sidewall, the wider the tire can be and not be so bulged out, at least to a point.

FWIW

295/50/15's after a lot of abuse on a cop wheel.


Tread depth looks pretty even inall the grooves

These are 305 50 15/s on the same wheel/car

told ya they would fit!