The John Deere 8400R tractor tire size is front 14.9R34 and the rear is 18.4R46.
Front tire14.9R34
Rear tire18.4R46
Front/rear setupDifferent front and rear tire sizes
Tire pressure35 PSI, 18 PSI
Rim diameter34 in front, 46 in rear
Ballast50 gal
John Deere 8400R Tire Size Details
Front tire size
14.9R34
Rear tire size
18.4R46
Front/rear setup
Different front and rear tire sizes
R1 ag tire size
380/80R38, 480/80R50
Front tire construction
Imperial radial
Rear tire construction
Imperial radial
Front section width
14.9 in
Rear section width
18.4 in
Front rim diameter
34 in
Rear rim diameter
46 in
Tire pressure
35 PSI, 18 PSI
Loaded rear tire ballast / fluid capacity
50 gal
Tire Size Comparison Chart
Front rim diameter comparison
This model
34 in
Average
17.1 in
Low
4 in
High
50 in
Rear rim diameter comparison
This model
46 in
Average
25.5 in
Low
0 in
High
50 in
John Deere 8400R Extra Tire Notes
Tire size note
The John Deere 8400R uses different front and rear tire sizes in this data: front 14.9R34 (34 in rim, 14.9 in width) and rear 18.4R46 (46 in rim, 18.4 in width)
Pressure note
For the John Deere 8400R with front 14.9R34 and rear 18.4R46 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 8400R rear 18.4R46 tires, the ballast figure captured in the answer is 50 gal. Liquid ballast capacity can change by tire brand, fill percentage, wheel setup and ballast fluid type
Front/rear matching note
The John Deere 8400R data shows front 14.9R34 and rear 18.4R46. 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.
