Tire Combination Guidelines (up to 40 km/h; 25 mph)

The size ratio of front wheels to rear wheels must produce a front wheel lead of 1.5 to 4 % on tractors with IVT transmission and 1 to 6 % on tractors with PowrQuad Plus and AutoQuad Plus transmissions.

CAUTION: Avoid personal injury or damage to tractor. Selecting tire sizes for an IVT-equipped tractor outside recommendations below could cause tractor instability when towing implements.

NOTE: In addition to above restriction on front wheel lead, tires exceeding a static loaded radius of 856 mm (33.7 in.) are not acceptable for use on 7130, 7230 and 7330 IVT tractors. See tire dealer to determine whether desired tire meets this requirement.

NOTE: In order to choose proper tire combination, MFWD clutch ratio for your tractor needs to be identified.

IMPORTANT: Any time a new brand or tire size is selected, see your John Deere dealer for recalibrating tractor control units and radar.

Available tires are grouped by rolling circumference (RC).

Rear tire groups 44, 45 and 46 are available for 7130-7330 tractors. Rear tire groups 46 and 47 are available for 7430 and 7530 tractors. The target rolling circumference for each group is shown below.

NOTE: Table shows target rolling circumference and should NOT be used to calculate front wheel lead. Exact rolling circumference values vary for each tire size. Use rolling circumference information from your tire dealer to calculate front wheel lead.

Tire groups and target RC

Group 39 (front)

3850 mm (151.6 in.)

Group 40 (front)

4055 mm (159.6 in.)

Group 41 (front)

4275 mm (168.3 in.)

Group 42 (front)

4505 mm (177.4 in.)

Group 44 (rear)

5000 mm (196.9 in.)

Group 45 (rear)

5270 mm (207.5 in.)

Group 46 (rear)

5550 mm (218.5 in.)

Group 47 (rear)

5850 mm (230.3 in.)

Tires of the same size but different brand name, as well as different size tires within the same RC group, may have slightly different rolling circumferences than their target values. Therefore, it is necessary to verify front wheel lead using procedure below.

Front tire group must be five groups lower than rear tire. This results in front/rear tire group combinations of 39/44, 40/45, 41/46 and 42/47.

Front-wheel lead verification procedure

  1. Select tires with suitable load-bearing capability.

  2. Select tires appropriate to the tractor's top speed.

  3. NOTE: Do NOT use estimated rolling circumference values in previous table to calculate front wheel lead. Exact rolling circumference values vary for each tire size. Use rolling circumference information from your tire dealer.

    Obtain rolling circumference for replacement front and rear tires from your tire dealer.

  4. Use tractor's model, transmission and MFWD clutch ratio in following chart to find front axle-to-rear axle speed ratio needed to calculate front wheel lead.

    Model/transmission

    MFWD clutch ratio

    Front axle-to-rear axle speed ratio

    7130 and 7230, PowrQuad Plus and AutoQuad Plus transmissions

    1.990

    1.943

    1.330

    1.363

    7130 and 7230, IVT transmission

    1.564

    1.597

    1.354

    1.326

    7330, PowrQuad Plus and AutoQuad Plus transmissions

    1.760

    1.800

    1.341

    1.311

    7330, IVT transmission

    1.485

    1.515

    1.348

    1.321

    7430 and 7530, PowrQuad Plus and AutoQuad Plus transmissions

    1.875

    1.917

    1.349

    1.319

    7430 and 7530, IVT transmission

    1.727

    1.758

    1.352

    1.328

  5. Calculate front wheel lead using following formula:

    FL = RCF x AR ÷ RCR

    FL = Front wheel lead

    RCF = Rolling circumference of front tire

    RCR = Rolling circumference of rear tire

    AR = Front axle-to-rear axle speed ratio

    Resulting front wheel lead should be between 1.01 (1 %) and 1.06 (6 %) for PowrQuad Plus and AutoQuad Plus transmissions and between 1.015 (1.5 %) and 1.04 (4 %) for IVT transmission.

    SAMPLE CALCULATION:

    • Tractor model: 7230 with IVT transmission and MFWD clutch ratio of 1.597

    • Group 41 front tire (16.9R28) with RCF = 4242 mm

    • Group 46 rear tire (20.8R38) with RCR = 5436 mm

    • From the chart, front axle-to-rear axle ratio (AR) for this tractor = 1.326

    • Applying formula: 4242 x 1.326 ÷ 5436 = 1.0347 (3.47 %)

    • Front wheel lead (FL) is between 1.015 (1.5%) and 1.04 (4%). Tire combination is acceptable.

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