cobra445,
Here are the specs for the 345 (8.5") rim:
Specification
Weight 14.70 LBS 6.67 Kg
Diameter 12.000 IN
Width 8.500 IN
Offset Depth 0.728 IN
Pilot Diameter 3.134 IN
Bolt Circle Diameter 4.501 IN
Hole Size 0.469 IN
Wheel Load 0.00 LBF
Rim Contour JA
Finish K
Note B
Found here:
https://jdparts.deere.com/servlet/c...er.PartDetails?lineNumber=13&screenName=quote
Here are the specs for the 10.5" wide rim:
Specification
Weight 17.88 LBS 8.11 Kg
Diameter 12.000 IN
Width 10.500 IN
Offset Depth 0.590 IN
Pilot Diameter 3.135 IN
Bolt Circle Diameter 4.500 IN
Hole Size 0.470 IN
Wheel Load 0.00 LBF
Rim Contour 10.5JA
Finish
Note
Found here:
https://jdparts.deere.com/servlet/c...er.PartDetails?lineNumber=14&screenName=quote
Appears that there is only .138" difference in the offset.
Also, here are the specs for the rim found on the GX345, with 24"x12"x12" tire:
Specification
Weight 14.26 LBS 6.47 Kg
Diameter 12.000 IN
Width 8.500 IN
Offset Depth 0.340 IN
Pilot Diameter 3.150 IN
Bolt Circle Diameter 4.500 IN
Hole Size 0.470 IN
Wheel Load 0.00 LBF
Rim Contour 8.5JA
Finish K
Note
Found here:
https://jdparts.deere.com/servlet/c...er.PartDetails?lineNumber=15&screenName=quote
Notice the offset has decreased. I know from personal experience that the 24"x12"x12" tire really fills the fender pan! I am not sure if 26"x12"x12" tires will fit, IMHO. YMMV.
FYI: I found these specifications by adding each rim to my cart. Once you have done that, from your shopping cart, click on the "Part No." for the item in question. This will bring up a page with relevant information.
I hope this helps.
Bill