Do any of you know what an R2 tire is? You don't, do you. Well, it is apparently the answer to the question--although maybe not the <font color=blue>ULTIMATE ANSWER</font color=blue>.
I have recently been enlightened by reading a hardcopy of the Goodyear Farm Tire Handbook (which I also believe is online with pictures). Here are Goodyear's definitions.
An R1 is "the most common type of lug tire used ... and is the tire to use for general dry land farming."
An R3 is "used on turf or in sandy areas where the disturbance of an aggressive lug-type tire is not wanted. R3s shallow, button-style treads are not designed for hard pulling but may give surprising traction on smooth, dry surfaces."
R4s "are found on tractors with backhoes and/or front-end loaders on construction and other industrial sites. These tires have shallow, durable lugs."
Now, to three types of tires specifically designed for use in wet soil. The first two rely on tread depth to increase traction. Goodyear says: "Tread depth is the biggest factor in wet soils, but as the soil dries out, deep lugs turn from assets to liabilities. In soil conditions most prevalent in North America, an R1 tire will pull better than an R1W." R1W?
R1W tires "were introduced in Europe for the wet soils found there. They fill a gap between the R1 and R2 tires and provide the right tire for areas with wet, sticky soils. The 'W' signifies wet soil service. R1W tires are defined as having a 20% deeper tread than an equivalent R1 tire, but actually range from 15 to 35 percent deeper."
R2s are even more tread depth aggressive. R2 tires "are for cane or rice or other crops grown in wet muck or flooded fields. R2 tires are about twice as deep as R1 tires..... Although R2 tires are excellent in the service for which they are intended, the widely-spaced lugs can cause problems with wear and vibration when roaded. R2 tires also do not pull as well as R1 tires in the drier soils typical of such crops as corn and beans."
Another approach is a high flotation tire. These are primarly used to avoid soil compaction and tread imprinting. Goodyear says they also allow "improved mobility, permitting the TERRA-TIRE to traverse mud or snow or soft sand that would often bog down a conventional tire." The high flotation tire Goodyear advertises for "wet muck" is the HF4 tire, which has high flotation and "extra deep tread".
I dont know how to post pictures. But perhaps one of the wizards could get the pictures of the following tires from the online Goodyear Farm Tire Handbook:
R1W = Goodyear Super Traction Radial DT810 and DT820
R2 = Goodyear Special Sure Grip TD8 bias ply and radial
HF4 = Goodyear Custom Flo-Grip (<font color=blue>THE ULTIMATE ANSWER?</font color=blue>) Gotta see the picture.