what is the widest tire that you can put on the crosslace rims.both 15's and 16's.plus how good will those look on a 1985 z28?

 

245 or 255/50R16 is what you'll usually find on GTA wheels but I've heard of people going as large as 275 or 295 but I've never seen it. They should look good on an IROC as long as the color goes with the paint. Black looks good on any color.

 

I would guess 275 is the largest. It's at least the largest I have heard of on the crosslaced wheels.

 

I have 255s on mine that were put on by the previous owner. They don't look like they're bulging or too wide for the rim at all. Going with a larger size I'd start worrying about uneven tread wear and having to go with a lower air pressure to compensate for it. I would be interested in seeing pics of larger sizes on them though just to see how they look