I have a 99 blazer ls with no lifts or spacers. I was wondering what the biggest tire size I could fit on the stock rims and possibly the measurements for the tires

 

30x9.5x15 or 255/70/15 will fit for sure on a stock non-ZR2 Blazer with no rubbing whatsoever.


Some people have had success with 31x10.5x15 or 265/70/15 on stock non-ZR2 trucks with claimed no-rubbing, but many many others have had to do at least 2" of lift to ensure that the tires won't rub the fenders or frame when turning and hitting a bump.


Personally, if you are keeping your truck at a stock height, I recommend 255/70/15s if you can find them, or 30x9.5s if you can't. I like the wider 255/70s myself.

 

Will the 255/70s give it a wider stance? I was looking at spacers but if these will give my blazer a wider stance I'll just get the 255/70s

 

I just put General Grabbers AT2's 255/70 on mine. They feel a tad heavier and I have to run less air because of the size. 29-30 psi is right if you do the math, look at load ratings, index ect. The tires alone were a net improvement but the real improvement comes when you fix the design flaw in the rear track width. It's too narrow, does not match the front, makes it sway too much, makes it steer wrong and is overall what makes these rigs a genuine POS to drive. Buy the 1 1/4" rear spacers. They are less than $40 on eBay and are hub centric. My new tires are cool but the spacers fixed it. Best advise I learned on this site. I started by fixing the front end, replacing sway bar bushings, shocks and tires. It was better but the spacers finally fixed the poor handling, wander, sway and overall death trap feel. If I had to do it over and I didn't get a smokin $250 craigslist deal on brand new 255's I'd stick with 235/75-15 because they are lighter. The spring rate on these vehicles is light. A heavier tire makes it worse.