A John Deere 2040 had a rear tire size of 13.6-28
Removing the front tire from the John Deere GT-235 involves lifting the vehicle with a jacking device, and removing the upper mounts holding the tire assembly. Now the tire can be removed.
There are specific store that carry that paticular brand John Deere. You can try searching online for a replacement or in the phonebook to try and find the tire.
rear 20x8-8
John Deere's website offers tractor parts. You can find them at their website: http://www.deere.com/en_US/homeowners/parts/index.html
The official John Deere website offers plenty of farming and tractor equipment. Heres a link to the website: http://www.deere.com/en_US/homeowners/parts/index.html
Above the front left tire on the frame is where it is supposed to be.
Mine is on the right side rear frame, near the rear tire.
Just like any other tubeless tire. You will remove the air from the tire and then get a pry bar and pull the bead over the outside part of the rim. Then you will get the other bead off the edge of the rim. My suggestions is to go to a local tire shop. Pay the fee, it is not worth thehassleand it will only take a few minutes.
Take the tire size into your local tire shop and they can get the tire and mount it for you. You can also go to a retail store, like Wal-mart and purchase the tire there. They should be able to get the size if it isn't in stock.
Any tire made for Tractors will work fine with the John Deere Tractor. Just be aware of the size of your tractor so you can be aware of what size tires you will need to put on the tractor itself.
http://www.tractorsmart.com/Farm_Tractor_Liquid_Tire_Ballast.htm will tell you how much water to put in your tire. It varies depending on tire size--a 30-horse Mahindra is going to take very much less water than a 500-horse John Deere.