Pacer, are you sure you have salt water in your tires? Man that has to be hard on the rims. There are several chemicals out there that won't rust the rims, so you might want to think about getting rid of that corrosive.
Salt solution is only in the my old Ford 3910, since new in 1989. Tires have tubes in them so no salt contact with the rims. I've had a couple honey locust tree thorn leeks over the years so there was probably some salt exposure when the tire guy drained them out to repair the tubes here at the farm. Lots of thorn leaks in the front tires but the old ford is 2WD and the front tires are not loaded, just tubed.
I had to replace one of the old original rear tires a couple years ago as the cords went bad in the center on an area about a foot in diameter.
They took the tractor wheel to the tire shop to replace the tire and tube so I went in to look at the rim inside while the tire was off.
It looked good but they cleaned and painted it with a rust inhibitor as part of the old process. The salt does cause rust, as I found next spring that the outside of the rim that had the tire changed had rusted at the rim nuts and where paint had been scratched or chipped on the rim. A little sanding, priming, and a spray can of Ford grey/white wheel paint and they look like new ( at least from a few feet away so the runs don't show)

The modern method, up here where we do get below zero once in a while, and what they used on my CNH which is 4WD and has tubless ag radial tires, is to use a solution similar to ( probably the same as ) windshield washer fluid. It is not as heavy per gallon as salt water so they really make the tires full. Even had some come out with the valves at high noon position.
I have since found that you are really supposed to check the tire pressure of filled tires with the valve at 6 p.m. so I got a wet pressure gauge. They are the same price as a dry one and look the same but have a spring to return the stem to zero and push out any water.
I must admit to using the old "look and kick" method on the old Ford to check the tires but since the tire guy said the cord destruction in the old rear tire may have been partially caused by not enough pressure, especially since I leave a back hoe on it most of the time now, I'm trying to be a little more conscientious about checking tire pressures.
The big storm that took off a lot of our house roofing 2 weeks ago also sheared off many trees and limbs about 15-20 ft in the air so I have been using the old tractor to pull down the "widow makers" I can get a chain on and hauling off tons of limbs and partial trees. A number of them are honey locust with big black 2" thorns so I slide back the barn door every morning praying not to see any flat tires.
The old tractor is all heavy metal construction and still my favorite do anything, fuel efficient, tractor. Sort of like BlueRivers Montana tractor.
One of the things I really don't like about the newer tractors is all the use of plastic. The FEL on the CNH is nice looking with all the hydraulic lines mostly hidden, except for the obnoxious quick disconnect center bracket on the side that is just tempting some tree to tear it off. There are a lot of fancy plastic covers on the cross frame, snap on covers over the zerks, and other places where tree limbs/trunks would destroy them in one hit/push/haul. All the fancy headlights, even with the FEL guard would probably be broken in one session of messing with trees.
I'm afraid fancy new tractors are getting like fancy pick up trucks, "too purty to get dirty" :2cents:
Ron