largest rear tire on stock wheelwell 69 dart

leblanc said

My 255/60's ride on an 8'' rim so 275's should get at least 9-9.5 right...
According to the tire chart I use a 275 is ideal for an 11'' rim but will squeeze on a 9.5, the wider the rim the better your handling and even tire wear will be. A narrow rim promotes wear in the center only, unless you lower the tire air pressure but that ruins the possibility of good cornering.

Click to expand...

A 9.5" rim is the MAXIMUM width rim for a 275/60/15. Those are straight off the tire manufacturer recommendations.

An 11" rim is not ideal for a 275/60/15, it's not even recommended.

Like I said earlier, if you were talking about a 275/35/18 it would be a different story because of the much shorter sidewall. But even in that case the recommendation is for a 9"-11" wide rim. The rim should be roughly the same width as the tread width, not the section width, unless you're talking about a very low profile tire. Not sure what "chart" you're using, but something isn't right.