Want 275s street slicks…it will be a damn close fit. should I chance it?

MRGTX said
Currently running 15x8, 0 offset wheels with 255/60/15. The car has an a-body width 8.75” with disk brakes so the fit may be unique.

They are pretty snug at the fender (had to slightly roll the lip to fit (likely exacerbated by the Hotchkis lowering springs and .5” lowering blocks). On the spring side, I have a bit of breathing room; about 22-24mm.

My extra wheels that the tires would go on have a +10mm offset/4.9” backspace. According to the tires n’ rims calculator, a 15x8 wheel with a 10mm offset (4.9” backspace) and 275mm tires would be the same distance from the fenders and 20mm closer to the springs.

They should fit but barely…

The Mickey Thompson tires that I’m looking at don’t come in 255 or 265 so I’m stuck with 275s.

I don’t want to mess with the fenders any more so spacers/more rolling isn’t preferable…

Would you chance it?

What tires are you looking at? Mickey makes 255/60x15 in both e.t.street R, and e.t.street SS, both of which are worlds better than a greasy rockhard t/a. I doubt you need the 275 street radial pro.
That said, i like wheels with too much backspace, lots more than too little. Too much bs can be easily fixed, and dialed in to perfection with QUALITY wheel spacers.
I have eleven,ten, and nine second cars with long studs that use spacers. One set i made of steel, slightly different for each side, one set i made of billet aluminum, and one set of bought aluminum cause i retired and didnt have access to the machine shop any more.