31X10.50's are totally doable on stock height 98 LS!
 

Less than a week into owning my 98 Blazer LS 160k, I threw down some dough today and put on a set of Goodyear Wrangler Duratracs, 31x10.5x15. At stock height after installing they barely barely rubbed on the corners of the mud flaps. I cranked the torsion bars, maybe 1 1/2" and now they're nowhere near rubbing. Thought at first I was gonna hafta do a set of 2" shackles in the rear also but after it was off the lift and sitting there I changed my mind. Stock rear height still has a very nice slight forward rake. I would love to upload a couple pictures I took but even using my phone apparently the files are too big. They don't accept very much for file size and pixel count! If anyone has a hint for me about that I'd really appreciate it. Really wanna get those pics up, the truck looks crazy tough! Totally transformed its appearance immediately!

Cranking the tbars is not considered stock height.

I'm aware of that. As I stated originally, at stock height they barely rubbed on the tip of the mud flap. Not a difficult modification to eliminate the problem and could easily drive with these....at stock height.

Yup until you pull into that first slightly angled driveway!!

Under certain circumstances, anything is possible. 9 out of 10 times I think it's safe to say, you could drive with 'em hassle-free

Most people that put bigger tires on do it for function, not looks. It isn't going to work off-road so well.

Well it's a case by case uncertainty. If whomever isn't sure about rubbing, crank up your torsion bars. Pretty simple

I have 2.5" RC upper control arms and lift shackles and the tbars are cranked plus a good bit of fender trimming and I still rub occasionally. Yes you can fit the 31s but I promise even with normal everyday driving you are going to rub. Especially while turning in reverse. No one is trying to be rude here either we just want you to understand that we have been there and know what its needed:)

Cranking the torsion bars isn't going to help at all off-road, that's the point I'm trying to make.

You rub because of your wheel offset.