That's really odd. The guy that built my jeep had the proper idea and remembered to also put a 265/70R16 in as a full size on a steel wheel...then there's two of my grands that had doughnuts for spares... Wtf guess those were mall rated jeeps.
Also, on the recommended tire size on the sticker it only gives the 225 as a option.

 

I'm running new 245 16 on my 04 wj and they work great. Looks like if I went any bigger though I'd be rubbin tires in the dips without a lift kit.

 

You're absolutely correct. I was messing around with one of my jeeps, changed the tires on a truck and the owner didn't want to keep his old mud tires so I kept them as they were in decent shape.... Tried them on my stock 2000 grand Cherokee and they rubbed on the inner front fender but only in the bumper portion... Had it flexed at all though, I would have tore the jeep up. Gave the tires away , they were 265/70R16 , the size my current 99 grand has on it, but it's lifted. Fml. Now I have KUMHO road ventures and they're not aggressive enough in my opinion

 

My dealer service manager tells me the 245/70R16s are the same diameter as the 225/75R16s, just 3/4" wider. The vehicle won't be rejected for warrantee service because it's got the 245s on it.