Thanks for the reply, J!
My truck has the factory-equipped 3.23 limited slip rear, so yea, it's pretty high geared and the taller of a tire I go WILL start to drag on performance.
I shouldn't have any issues with the speedo and tire pressure thing, since my brother can take of that in his GM shop. The reflashed speedo will, I believe, cost me about $50, but the tire pressure flash won't. At least I have easy access to remedies on those situations, however.
I'm still up in the air on the size, simply because once I get thru the rough terrain......it's all highway, really. So, some reduced RPM's out there isn't necessarily a bad thing. We only have one stoplight in this area
and I might hit it once a week. My point is.....very few stops and starts. I'm just navigating some rocky, muddy terrain and then highway stuff.
My brother IS a little bit concerned that 285's would cause my tires to rub on sharp turns, but he isn't positive about it.
Sigh. I remember these growing pains on my '70 Chevelle when I was younger. I should have known I couldn't leave this truck alone. It's just in my nature to tinker.
Thanks!