SEEN 21 AND 23'S WITH 18.4R38,20.8R38, 18.4R42 AND20.8R42. SEEN A FEW 16 SERIES WITH 18.4R38'S. THE 18.4r38S ARE A LITTLE SHORTER THAN 30.5-32'S. wHE HAVE ONE COMBINE WITH 30.5'S THAT WE HAVE A SET OF 18.4R38 SNAP ON DUAL FOR WHEN IT GETS WET.
Consider going to floater tires. The 2388 we bought last winter had 77x44s with super lugs (not sure if that is correct terminology but have deep lugs like a rice tire) on it. I wanted duals but IHboog insisted on the wide tires. I have a friend that has one combine with duals & one with the floaters & he highly recomended the floaters as did our tireman. We have only ran it one season and it was a dry fall but I really like the settup.
The floaters have a lot more rubber on the ground than 18.4x42s and you don't have the problem of mud buildup between the tires that duals have. Though we had a fairly dry fall we did have some rains and I was surprised how quick we could get back in the fields with out leaving ruts, at least a day ahead of neighbors with conventional tires. Most tracking we saw was the depth of the lugs. Fields were wet enough that we couldn't run the auger cart which has 30.5s