I think 16 inch tires may be easier to get than 17 inch tires. That being said I would look at 235/85R16 tires. Those tires are fairly tall and farly skinny at about 31.7 inch diameter. About the same height, but a little skinnier would be a 750/16 tire. I mention these tires because I assume you would use them for all 4 wheels. The skinnier tires work better with the manual steering. It is also possible to go bigger on the back with 35 inch tires available for most rim sizes. Check your clearences first. I don't own nore have I ever owned a 48 3/4 ton. Check with the local and online tire stores to get an idea of what tires are available/afforable.
