I habe a 2000 xj i habe put a 5.5 rubicon expreas long arm kit on it the wheels i have on it now are 15x8. I took a straight edge amd measured from back of bolt pattern to bottom of straight edge amd got 3.75 inches. Now is that enough of an offset to fit 33x12.5r15?

Yes you'll have plenty of clearance. That is typical of what most people run. 3.75" is pretty close to the widest wheels you can get. Remember that the less backspacing there is, the farther out the wheels will poke.

Tgis is current wheel i measured from backside of bolts to bottom of a straight edge to the bead

Measure like this ^ (to back of wheel, not face)

If you are getting 3.75", then you are at the same backspacing as mine. I have 5" of lift and 33x12.5s on my 90. You'll still need to trim the fenders a bit, but can still use the stock wheel flares. Will also need to adjust the steering stops, the tires will rub on the LCAs.

I got them on didnt have to to trim vut if i so turn all thw way i do rub the LCAs but if i just put wheel spacers would it push it out far enough?

Don't use spacers. There is a bolt on the back of the knuckle that hits against the inner 'C', that is your steering stop. Pull the bolt out, put a washer or two under the nut, reinstall. That will reduce your turning radius enough to prevent rubbing. You won't notice a reduction of steering. Will still be able to make tight u turns.

For more info, check out this article: https://kevinsoffroad.com/adjusting-...-yj/#gsc.tab=0

You WILL having rubbing if you flex out the suspension. Hit a good bump in the road while turning and the front may rub. Come down a good hill at speed and the rear will likely rub. Tire shredding, fender bending goodness. Speaking from experience. The best way is to flex out the suspension, and measure for bumpstops. Due to the fact the tires are larger, the bumpstops must be longer. You can reduce the required length if you trim the fender opening larger. Wont be a big deal on the street, but can become a real problem off road.

Ill adjust the the steering limitation thanks. Also will be getting a 2nd set of wheels amd tires for offroading strictly probably run a 31 10.5 to give more clearence. I have. 4 10 gears.

Those BFGoodrich ATs are suppose to be a decent tire. I wouldn't suggest another set of tires just to gain some extra clearance. You can trim the fenders and still use the stock wheel flares. It's a little bit of work and no one will know you did it, it won't show. After that, bump stop it. Even with 31s you'll need to adjust your bump stops.

I run 4.10s with my 33s. It does fine.

They are a freaking great tire. I currently have some Cooper at3. They are nice to... the luxury of working at a tire shop haha