The John Deere 420 tractor tire size is front 18×8.50-8 and the rear is 23×10.50-12.
Front tire18×8.50-8
Rear tire23×10.50-12
Front/rear setupDifferent front and rear tire sizes
Tire pressure35 PSI, 18 PSI
Rim diameter8 in front, 12 in rear
Ballast12 gal
John Deere 420 Tire Size Details
Front tire size
18×8.50-8
Rear tire size
23×10.50-12
Front/rear setup
Different front and rear tire sizes
Original factory tire size
Front 18×8.50-8, Rear 26×12.00-12
Replacement tire size
Front 4.80×4.00-8, Rear 23×10.50-12
R1 ag tire size
4.80×4.00-8, 23×10.50-12
Front tire construction
Flotation/implement tire
Rear tire construction
Flotation/implement tire
Front section width
8.5 in
Rear section width
10.5 in
Front rim diameter
8 in
Rear rim diameter
12 in
Approx front overall diameter
about 18 in
Approx rear overall diameter
about 23 in
Tire pressure
35 PSI, 18 PSI
Loaded rear tire ballast / fluid capacity
12 gal
Tire size alternatives / conversions
6.00-16, 11.2-24
Tire Size Comparison Chart
Front rim diameter comparison
This model
8 in
Average
17.1 in
Low
4 in
High
50 in
Rear rim diameter comparison
This model
12 in
Average
25.5 in
Low
0 in
High
50 in
John Deere 420 Extra Tire Notes
Tire size note
The John Deere 420 uses different front and rear tire sizes in this data: front 18×8.50-8 (8 in rim, 8.5 in width) and rear 23×10.50-12 (12 in rim, 10.5 in width)
Pressure note
For the John Deere 420 with front 18×8.50-8 and rear 23×10.50-12 tires, the pressure values captured in the answer are 35 PSI, 18 PSI. Tire pressure is load-dependent, so use this as a reference value rather than a universal setting
Ballast note
For the John Deere 420 rear 23×10.50-12 tires, the ballast figure captured in the answer is 12 gal. Liquid ballast capacity can change by tire brand, fill percentage, wheel setup and ballast fluid type
Official information note
Mistakes do happen. Tire sizes can change by year, axle, wheel/rim option, tyre brand, tread type and local market. Please check the tire sidewall, operator manual and official deere.com website for official information.
