Handling Front Axle Overload of Certain MFWD Tractors

FRONT AXLE OVERLOAD OF CERTAIN MFWD TRACTORS

Technical Bulletin: F-108-
Date: April 2020

In some situations, Mechanical Front Wheel Drive (MFWD) tractors can be ordered from the manufacturer in a configuration with front axle singles and a weight package that overloads the front tires. Firestone AG has determined that the tires may experience early removals due to such overloading, and has been in communication with tractor manufacturers to address this subject. In the meantime, this bulletin is intended to assist dealers and tire service professionals in their evaluation of tires and tractors, and their responses to customers in these situations. An example tractor is shown below.

In the case of MFWD tractors with overloaded front axle singles, early removals of tires have been most commonly found to have lower sidewall separations.

Tire conditions of any kind caused by overloading are not warrantable per the Firestone AG Limited Warranty.
The Firestone AG Limited Warranty exclusion also applies to overloading that may be due to the tractor configuration as originally delivered from the tractor manufacturer dealership and subsequently operated in the field.

Customers with damaged tires due to overloading caused by the configuration of the tractor as it was ordered/delivered are advised to contact the tractor manufacturer to notify them of the condition and to seek any remedy.

TIRE REPLACEMENT RECOMMENDATIONS

Do not replace damaged tires that were overloaded due to the tractor configuration with the same tires; the same unsatisfactory outcome is to be expected. Depending on the tractor and service conditions, the front axle load may need to be accommodated in one of the following ways:

A tire with a higher load index may be applied.
If a customer needs a tire with a specific section width, front weights may need to be removed along with the application of a tire with a higher load index.
For tractors with front-mounted fertilizer tank(s), converting the front axle to a dual configuration may be the only way to carry the load.

In all situations, verify proper load and rim/wheel size for the tire, and properly set inflation pressure.

TIRE REPLACEMENTS FOR AXLE LOAD CAPACITY INCREASE

Corrective action for load capacity will depend on the actual tractor configuration, installed accessories, and service conditions in the field. The information in the table below, although not exhaustive of all possibilities, may be suitable in certain situations.

	Original Size	Replacement Size	Comment
RCI Group 42	380/85R34 137B	IF380/85R34 149B	May need to remove suitcase weights
	420/90R30 142B	IF420/90R30 151B
	420/90R30 142B	480/70R30 152B
RCI Group 43	380/80R38 142B	IF380/80R38 149B	May need to remove suitcase weights
	380/80R38 142B	VF380/80R38 154B
	420/85R34 147B	IF420/85R34 152B
		VF420/85R34 157B
		480/70R34 155B

BACKGROUND: WEIGHT STUDIES

Firestone AG evaluated the weights of various tractors that have experienced front tire sidewall separations and determined that the tire conditions are the result of overloading. Tractor models that tend to have overloaded front axles are MFWD with 200+hp such as John Deere 8R, Case IH Magnum, New Holland GENESIS T8, Massey Ferguson 8700, and Versatile MFWD—each equipped with 380 or 420 section width front tires (as singles) and with additional front-mounted load from more than six suitcase weights and/or use of a fertilizer tank. Examples of actual configurations are shown in the table below.

For the Front Axle	John Deere 8295R	John Deere 8345R	John Deere 8295R
Axle Type	1300 Series	ILS	1300 Series
Tire Types, as Singles	420/85R34 147B Radial All Traction DT	380/80R38 142B Radial All Traction DT	420/85R34 147B Radial All Traction DT
Additional Axle Weight	22 suitcase weights	22 suitcase weights	22 suitcase weights 275 gal fert. tank
Actual Axle Load	15,500 lbs	16,000 lbs	20,600 lbs
Tire Load Capacity	6,800 lbs per tire, 13,600 lbs per axle	5,840 lbs per tire, 11,680 lbs per axle	6,800 lbs per tire, 13,600 lbs per axle
Tire Overload	950 lbs per tire (+15%)	2,160 lbs per tire (+37%)	3,500 lbs per tire (+51%)

For questions or assistance, please contact your Regional Sales Manager or Firestone AG Field Engineering.

Firestone AG Field Engineering

1-800-847-3364