Technical Bulletins

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

 

480/70R30  152B

 

RCI Group 43

380/80R38  142B

IF380/80R38  149B

May need to remove suitcase weights

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