I see here for example: http://www.millertire.com/products/lawn-garden-tires/5-12/5-12-regency-ag-tractor-4-ply/
That it says This tire is 20.8" tall, the 5.00-12 is 22.8" tall. not for use with 4wd.
So 5-12 is not necessarily the spec I am going for? I just need to make sure its 22.8 inches...