I have a 2004 XJ8 with the 18x8" stock wheel. I like the way it looks but I'd like to put the biggest tire that will fit that wheel on this car. Has anyone tried? I've read others upgrading to larger wheels but can't find any info on bigger tires with the stock wheel.

Options:

-285/40r18 (some say it's too wide for an 8" rim)
-275/45r18 (.4" increase in diameter, not bad)
-265/45r18 (would like it wider if possible)

Stock tire:

-235/50r18

 

I put on 10mm wider Hankooks, the factory size looked wimpy and now they look tough. Noise level is lower, sticks like glue, and no suspension contact.

 

What tire size would that be, 245-50-18?

Thanks!