Correction Factors for Other Tire Sizes

To calculate ground speeds for tractors equipped with rear tires other than 18.4 R30 1442 R1 tires, multiply speeds shown in GROUND SPEED ESTIMATES by the correction factor for the appropriate tire size found in the table.

Be sure to use correct ground speed estimate for your transmission type. Use creeper transmission ground speed estimates, if so equipped.

Example: Forward B-2 (PowrReverser™ Transmission) at 2400 engine rpm with 19.5L-24 R4 tires.

7.07 km/h (4.49 mph) x 0.88 = 6.22 km/h (3.95 mph)

Tire Size	Correction Factor
19.5L-24 R4	0.88
16.9-30 R1	0.96

NOTE: Speed and correction factor information above is based on rolling circumference information from GoodYear Farm Tire Data Book. Rolling circumference dimensions for “like” size tires vary by manufacturer.