I have a chance to pickup a set of tires and rims size 26x12-12 and 18" fronts cheap. I have a 2018 x580 tractor with 24x12-12 on it. and 16" on the front. Would the bigger tires work? Or would it do damage to the tractor?
Actually, the larger tires/wheels are only an issue for SOME decks on SOME models of garden tractor, and you should have no issue with either front or rear mounted attachments in any case. The increase in tire outer diameter may not be as much as you might infer from the size ratings, as many vendors' tires of the same nominal size vary in actual outside height and width when mounted to the same size wheel -- so see the specific manufacturer's data for the actual diameter. Some inexpensive import tires have difficult to find specifications in this regard, so do your homework.
Carlisle publishes good information on their tires, and my 322 tractors shown below have that brand in both stock size showing a mowing deck, and the larger tires (on the 1992 model with the center blade that I made...) The added ground clearance was a marginal benefit for the center blade application. The larger tires did not interfere with the mower in use, but when the deck was raised fully you had to be careful not to turn too sharply as the larger front tires would very slightly rub on the front edge of the 46 inch deck when it was used with the larger tires.
Not so much the problem with accessories as it will be with the transmission. Take a look at the transmission specs for your tractor and you'll find a rear tire size maximum height. That height is given due to the amount of torque required to turn larger tires under load. Larger tire = more torque required, and more strain on the transmission. This could result in damaged parts and even twisted or broken axles.
I don't know the specifics of the final drive on the later X series tractors, but the driveline on the open frame 318/322/332/420/430 tractors is very robust. Further, the difference in radius of a 26 inch wheel/tire is only about 8% more than a 24 inch one and 13% more than a 23 inch setup. No mechanical engineer working at Deere designs anything with less margin in the rating than this as typical margins are AT LEAST 100% or more. I suspect this is also true of the designs at Sunstrand (Sauer-Danfoss now...)
I have followed these user forums for many years and have not seen any reference to taller tires causing issues of this nature. My own experience with the 322 is that for all uses including tiller, center blade, front blade and Johnny Bucket SR attachments where the work was rather heavy duty there were absolutely no problems. Normal maintenance was always performed but no signs of any unusual wear, loosing of bolts, leakage, etc.
Torque is torque and you can't change the laws of physics. But, as long as you've not heard of damage being done it must work just fine. Using your logic I encourage the EU to find the largest rear tires he can find and put them on. Thanks for clearing that up.:lol: