The John Deere 9420T tractor tire size is front 18.4R38 and the rear is 710/70R42.
Front tire18.4R38
Rear tire710/70R42
Front/rear setupDifferent front and rear tire sizes
Tire pressure18 PSI, 35 PSI
Rim diameter38 in front, 42 in rear
John Deere 9420T Tire Size Details
Front tire size
18.4R38
Rear tire size
710/70R42
Front/rear setup
Different front and rear tire sizes
R1 ag tire size
18.4R38, 14.9R24
Front tire construction
Imperial radial
Rear tire construction
Metric radial
Front section width
18.4 in
Rear section width
710 mm
Rear aspect ratio
70%
Front rim diameter
38 in
Rear rim diameter
42 in
Approx rear overall diameter
about 81.1 in
Tire pressure
18 PSI, 35 PSI
Tire size alternatives / conversions
18.4R38, 20.8R38
Tire Size Comparison Chart
Front rim diameter comparison
This model
38 in
Average
17.1 in
Low
4 in
High
50 in
Rear rim diameter comparison
This model
42 in
Average
25.5 in
Low
0 in
High
50 in
John Deere 9420T Extra Tire Notes
Tire size note
The John Deere 9420T uses different front and rear tire sizes in this data: front 18.4R38 (38 in rim, 18.4 in width) and rear 710/70R42 (42 in rim, 710 mm width)
Pressure note
For the John Deere 9420T with front 18.4R38 and rear 710/70R42 tires, the pressure values captured in the answer are 18 PSI, 35 PSI. Tire pressure is load-dependent, so use this as a reference value rather than a universal setting
Front/rear matching note
The John Deere 9420T data shows front 18.4R38 and rear 710/70R42. When changing either size, front/rear rolling circumference and lead/lag need to stay within the correct range
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.
