Howdy, if the tire has been on since 2014 and is square on the bottom , it's time.
It's not really that hard, but you do need a lift to get up 10-12 inches or so. secure well, you may also want to install a lift plate to protect the bottom casing, Jack-Be- Quick works well
Before lifting, loosen the axel nut, and brake reaction bolt. You'll also need to remove your mufflers.
REmove the axel part way and lift the brake assembly out of place and place upon something high enough to keep from staining the brake line.
Before removing the axel completely, support the wheel so it doesn't just fall out of the splines. The wheel wants to stay put, but just incase. I used a small floor jack to lower the wheel, and again to raise the wheel up to push back onto the splines.
There is a shim about an 1 wide or so on the right side of the wheel, remove and keep it safe somewhere.
Have the new tire put on the wheel.
At reassembly, you want to lube the splines at the wheel and off the gear box. Be sure to use the proper grade of Moly paste, lots of rec's at this site, do a search.
You should also so the rear drive shaft splines and this time. Remove the 4 nuts holding the bevel box in place. Slide the bevel box rearward and few inches to expose both the male and female splines. Molythem as well.
REassemble using proper torques. See manuel for these numbers.
Hope this gets you started, do searches here and you'll get some more insight, but the above is the gist of things.
Good Luck
Hoopla