I just put a 2.5" lift on my 2001 4 door LT Blazer and put 31s with -18 offset on her for wheels and when I turn the wheels fully she rubs my fenders. I've seen lots of pictures of blazers with the same lift and bigger wheels and saying they didn't have to make any cuts on the wheel well close to the doors. Just wondering how I should go about fixing this.

WHEELS
15x8 -18
TIRES
31"x10.5

 

Off the top of the head, I'm pretty sure the stock backspacing is 50 mm for 4wd Blazers. This is also true for the ZR2 that had the 31x10.5 tires. But those had a wider axle and front suspension to accommodate those tires.

After I did a 1.5" lift, I had 30x9.5 and 31x10.5 tires test fit on my Blazer. The 31s would rub the frame rail when the steering wheel was at full stop. I then decided to have the 30s installed.

It would appear that your 18mm backspacing wheels prevent the wheels rubbing the rails but not the wheel wells.

When I was doing research on the options for doing a lift, I discovered that those who did lifts, at least the 1.5" lift and not the 2.5" from RC, would have to trim the rear of the front wheel wells and turn in the inner edge of the front wheel wells to prevent rubbing.

I looked to see if I downloaded any pictures of the trimmed fender wells but I could not find any.

Perhaps someone else can help with more details.

 

Christine pretty much covered the problems. Much less backspace on the wheels but also one inch wider has led to your rubbing issues. Pretty easy to trim the fender wells, but don't be surprised if you go offroad and find that the rear tires start rubbing when you get some flexing of the suspension.