3-95 Section 3 - Operation

Tire Selection

Tire Selection

Selecting the proper size and type of tires is important in achieving maximum tractor efficiency.. Various sizes and types of tires are available for your tractor.. Refer to table below for approved tire sizes and articulation block configurations for your tractor..

NOTE: If a specific size of tire or tire configuration is not listed under a particular model, do not attempt to install that size tire.

The tires selected for your tractor must be able to support the weight of the tractor and equipment.. The tires must also be able to provide adequate tire traction to utilize the tractor engine horsepower and turn it into useful drawbar horsepower..

You will have to adjust the ballast, tire pressure and tractor weight split between the front and rear axles for various loads and conditions to achieve the best ride and performance..

Always maintain the proper air pressure in the tire to carry the load.. Do not over inflate radial or bias ply tires.. Radial tires will work with LOWER air pressures.. Radial tires will show up to 20% sidewall deflection or bulge when properly inflated..

The force that enables the tires to drive the tractor must be transmitted through the tire sidewalls.. The tires work best when all the tires on a given axle are working at the same rate..

Think of them like a shock absorber; they must respond the same way to share the load equally..

Factors Determining Best Tire Performance

Good Performance

•Proper air pressure for the load

•Proper sidewall deflection

•8%-15% wheel slip

•Proper tire size for expected load

•Less than 50% fill of liquid ballast

•Maintaining equal tire pressure in all tires on a given axle

Poor Performance

•High or low air pressure

•Stiff sidewalls

•High or low wheel slip

•Overloaded or underloaded tire

•Treating tires on an axle differently..

Refer to “Ballasting” later in this section for proper tractor weight procedures once the tire size has been selected..

Tire Configurations

Tire Size

Articulation blocks

Duals

Triples

 

20..8R42 R1W

None

38 deg

520/85/42 R1W

None

38 deg

520/85R46 R1W

None

38 deg

 

 

 

620/70R42 R1W

None

33 deg

 

 

 

650/65R42 R1W

None

33 deg

650/85R38 R1W

None

33 deg

710/70R38 R1W

None

N/A

 

 

 

710/70R42 R1W

None

N/A

 

 

 

800/70R38 R1W

38 deg

N/A

850/60R38

38 deg

N/A

900/50R42 R1W

38 deg

N/A

 

 

 

435/485/535