Tyre Learn
INTRODUCTION

Goodyear maintains a wide product offering of agricultural and industrial tyres in radial and bias construction for the original and replacement markets.

A full range global supplier for over 100 years, Goodyear has a long tradition and a wealth of tyre expertise in the agricultural and industrial industry.

Backed by specially trained technicians and engineers, Goodyear’s research and development continue to develop and create new line of innovate farm and industrial tyres.

Goodyear Tyres meet the demanding performance requirements of sophisticated machinery manufacturers, machine dealers, contractors, farmers and end-user.

Goodyear understands its valued customers and is committed to delivering total customer satisfaction with products capable of coping with the most demanding and variable work conditions.

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RADIAL AGRICULTURAL TRACTION DRIVE
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Narrow 
Suited for row crop and other narrow applications. The large rim diameters and narrow cross section are perfect for easy crop clearance. Rounded shoulders reduce soil and plant damage. Diameters are compatible with existing sizes for easy interchangeability.

Standard
The perfect choice for all round field and road service.

Wide
The great selection for outstanding traction. A net benefit in treadlife and stability versus standard tyres and still compatible with most popular rim widths.

Super Wide
The great fit for modern, fast and powerful tractors. Very well balanced performance profile for efficient field and road work.

Volume
The tyre of choice for powerful and heavy machines, providing increasing air volume and a larger footprint, giving extra load capacity at reduced inflation pressures for tractors and harvesters.

Super Volume
Extreme oversized tyres to provide the maximum in flotation (reduced soil compaction characteristics while retaining maximum traction. Excellent side stability. Suited for harvesting machines and tractors.

THE OPTITRAC RADIAL FARM TYRE LINE
 
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TECHNOLOGY

Radial Farm Tyre
(Can be either tube-type or tubeless. The example illustrated here is a tubeless version).image004_2

  1. Tread: Helps to provide traction and wear and protects the carcass underneath.

  2. Belt: Multiple, low angle, cord layers provide strength to the tyre, stabilize the tread and help to prevent penetrations into the carcass.

  3. Sidewall: Helps to provide protection for the plies and withstands flexing and weathering.

  4. Ply: The radial (90°) plies transmit all load, braking and steering forces between the wheel and the surface and withstand the burst loads of the tyre under operating pressure.

  5. Innerliner: A layer of rubber in tubeless tyres specially compounded to help prevent loss of air.

  6. Bead bundle: The steel bead bundle properly seats and seals the tyre on the rim and maintains it in position.

  7. Apexes: Rubber fillers in the bead and lower sidewall area to help provide a progressive transition from the stiff bead area into the flexible sidewall.

  8. Chafer: A layer of hard rubber that resists erosion of the bead zone by the rim flange.

Bias (Crossply) Farm Tyre
(Can be either tube-type or tubeless. The example illustrated here is a tube-type version).image005_2

  1. Tread: Helps to provide traction and wear and protects the carcass underneath.

  2. Sidewall: Helps to provide protection for the plies and withstands flexing and weathering.

  3. Carcass: The diagonal ply carcass transmits all load, braking and steering forces between the wheel and the surface and withstands the burst loads of the tyre under operating pressure.

  4. Bead bundle: The steel bead bundle properly seats and seals the tyre on the rim and maintains it in position.

  5. Apexes: Rubber fillers in the bead and lower sidewall area to provide a progressive transition from the stiff bead area into the flexible sidewall.

  6. Chafer: A layer of hard rubber coated fabric that resists erosion of the bead zone by the rim flange.

  7. Tube: A separate air chamber, compounded to help prevent loss of air, inserted into tube-type tyres.

The reinforcing cords extend diagonally across the tyre from bead to bead at an angle of 30 to 40 degrees to the centreline of the tyre. Each successive ply or layer of body cord runs in the opposite direction which results in a crisscross pattern.

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The plies of reinforcing tyre cord extend from bead to bead at a 90 degree angle to the centreline of the tyre. Directly on top of the radial plies and under the tread is a full length belt made up of several plies of cord or steel. This belt runs circumferentially around the carcass. The cords are placed in the belt at a low angle of 15 to 25 degrees.

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TYRE MARKINGS

image010The position of the major tyre markings are as shown:

  1. Tyre Section width (mm or inches).

  2. Aspect ratio SH/SW.

  3. Radial construction (R=Radial).

  4. Rim Diameter (inches).

  5. Load Index 40 km/h (Max. load per tyre).

  6. Load Index 50 km/h (Max. load per tyre).

  7. Speed Symbol.

  8. Safety warning.

Flange Cover

Goodyear was the first manufacturer to pioneer a bead-to-sidewall configuration which avoids the penetration of soil and foreign object between the rim and the tyre. The protection called flange cover has greatly reduced tyre breakdowns and damage.

Goodyear was the first manufacturer to pioneer a bead-to-sidewall configuration which avoids the penetration of soil and foreign object between the rim and the tyre. The protection called flange cover has greatly reduced tyre breakdowns and damage.

Standard Type

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Flange Cover

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Pry Notch
The “pry notch” in the flange cover helps to provide a convenient spot for the dismounting tool to get between tyre bead & rim without damage to the tyre.

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TYRE DIMENSIONS

Tyre companies throughout the world are members of regional tyre manufacturers’ associations (ETRTO for Europe), which establish tyre dimensions and tolerances, load carrying capacities and inflation pressures for the different tyre categories and sizes. The basic tyre and rim dimension nomenclature is explained below: image015

Outside Diameter (OD):The diameter of an unloaded tyre, mounted on its recommended rim and inflated to recommended pressure.

Section Width (SW):The width of the inflated tyre section, excluding any lettering or decoration.

Section Height (SH):The distance from the bead seat to the outer tread contour of the inflated tyre - at centreline.

Static Loaded Radius (SLR):The standing height from the road surface to the axle centre under nominal tyre load/inflation conditions.

Loaded Section Width (LSW):The width of the loaded cross-section.

Rim Width (RW):The width of the rim measured from flange to flange.

Rim Diameter (RD):The diameter of the rim measured from seat to seat.

Flange Height (FH):The height of the rim flange measured between the seat and the outer flange contour.

Deflection (D):The difference between one half the overall diameter minus SLR.

Rolling Circumference (RC):The distance a tyre travels in one revolution. RC is given for normal load, inflation pressure and speed.

Example of Traction
Tyre Size Marking

Example of Front Wheel
Tyre Size Marking

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Sample of Traction
Tyre Size Marking

Example of Implement
Tyre Size Marking

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SPEED SYMBOL AND LOAD INDEX

In the past, the load carrying capacity of a farm tyre was indicated by the Ply Rating. Through ETRTO (the European Tyre and Rim Technical Organisation), the tyre manufacturers have established more convenient parameters to determine tyre performance. The parameters include the load index (LI) of the tyre as well as its speed symbol. The sidewall marking is illustrated.

Speed SymbolSpeed (km/h)
A15
A210
A315
A420
A525
A630
A735
A840
B50
C60
D65
E70
F80
G90
For specific field and road conditions, please consult our load & inflation tables.

The load index indicates the maximum load a given tyre can carry at the maximum speed indicated by the speed symbol.

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Tyre and Rim Association (T&RA) Industry Tyre Type Codes

TRACTOR STEERING WHEEL TYRES
F-1Agricultural Single Rib Tread
F-2M Agricultural Multiple-Rib Tread
F-2Agricultural Multiple-Rib Tread
F-3Industrial Multiple-Rib Tread
REAR TRACTOR TYRES
R-1Drive Wheel, Regular Tread
R-1W Drive Wheel, Wet Traction Tread
R-2Cane and Rice, Drive Wheel, Deep Tread
R-3Drive Wheel, Shallow Tread
R-4Industrial Tractor, Drive Wheel, Intermediate Tread
HF-1High Floatation, Shallow Tread
HF-2High Flotation, Regular Lug Tread
HF-3High Flotation, Deep Lug Tread
HF-4High Flotation, Extra Deep Tread
IMPLEMENT TYRES
I-1Rib Tread
I-2Moderate Traction Implement
I-3Traction Tread
I-6Smooth Tread
F-1Rib Tread with highway speed approval
CONVERSION TABLE
DISTANCESURFACE
1 inch= 25.4 millimetres1 square inch= 6.4516 cm2
1 foot= 12 inches
= 0.3048 meter
1 square foot= 929.0304 cm2
1 yard= 3 feet
= 0.9144 meter
1 square yard= 0.83612736 m2
1 mile= 1,760 yard
= 1.609344 kilometer
1 are= 10 meter x 10 meter = 1,000 m2
1 British nautical mile= 1.8532 kilometer1 acre= 4.046.8654 m2
= 0.40468564 hectare
1 international nautical mile= 1.852 kilometer1 hectare (ha)= 2.4710538 acres
= 100 meter x 100 meter = 10,000 m2
1 revolution per mile= 0.62 revolution per kilometer1 square mile= 2.5899881 km2
VOLUMESPEED
1 cubic inch= 16.3871 cubic cm31 mile per hour= 1.609344 km/hr
1 cubic foot= 28.316847 dm31 foot per second= 0.3048 m/s
1 cubic yard= 0.76455486 m3PRESSURE
1 gallon (Imperial)= 4.54609 L1 psi= 6.894757 kPa
1 gallon (U.S.)= 3.785412 L1 standard atmosphere= 101.325 kPa
1 quart (Imperial)= 1.136522 L1 bar = 100 kPa= 14. 5 PSI
1 quart (U.S.)= 0.94635264 L.
WEIGHTTEMPERATURE
1 pound= 0.4536 kilogram1 fahrenheit= (9/5 x degr. Celsius) + 32
1 metric ton= 1,000 kg = 2,205 pounds1 celcius= (degr. Fahrenheit - 32) x 5/9
1 english ton= 2240 pounds
= 1,016 metric ton
= 1016 kg
POWER
1 US ton= 2000 pounds = 0.9072 metric ton
= 907.2 kg
1 horsepower (hydraulic)= 746.043 W = 0.746 KW
.1 horsepower (brake)= 745.69999 W = 0.746 KW
LOAD BONUS TABLES

At operating speeds different from the nominal speed indicated on the tyre, variations in tyre load carrying capacity related to vehicle speed apply. Load bonus tables identify these variations by tyre types. Speed is either the vehicle's maximum speed capability or any overriding speed limit. Maximum load includes all possible field and vehicle/usage variations. For standard operating speeds please consult the basic load and inflation tables. “Cyclic load” or cyclic operating duty cycle is an application with appreciable total load fluctuation e.g. combine grain tanks which are repeatedly filled and emptied. Unloading is to occur before off-field transport. Maximum load may not be carried for more than 1.5 km before unloading operations begin. Maximum load per tyre includes all possible field and vehicle/usage variations. For cyclic loads, no bonus load is permitted for hillside applications exceeding 11 degree (20%) slope. Consult the rim and wheel manufacturer for conformation of rim/wheel strength for the intended service.

In case of doubt, always consult your local Goodyear representative for load and pressures to be used in practice.

Load Bonus Table – Traction orDrive Tyres – Agricultural Use

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For field applications with high and sustained torque, values for 30km/h apply
* For cyclic loads only
** Applies to 6 PR and above For stationary service (0 km/h), overloads higher than those indicated in the above table may occur. Consult your Goodyear representative prior application.
For tyres used in dual service, indicated tyre load limits must be reduced by 12%. The indicated increase in inflation pressures must be maintained.

Load Bonus Table –A6 Speed Implement Tyres

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(*) reference load is Free Rolling (FR) Load Index
(**) reference load is Drive Wheel (DW) Load Index
High Load Variation (HLV): laden vehicle load is at least twice the unladen one.
For HLV conditions, maximum driving distance may not exceed 1km.
For HLV conditions, inflation pressure must increase by 37%.
For tyres in steering application, increase pressure by 20% and reduce load to 80% of maximum load of free-rolling application.

Load Bonus Table – A8 Speed Implement Tyres

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High Load Variation (HLV): laden vehicle load is at least twice the unladen one.
For HLV conditions, maximum driving distance may not exceed 1km.
For HLV conditions, inflation pressure must increase by 30%.
For tyres in steering application, increase pressure by 20% and (*) reference load is Free Rolling (FR) Load Index reduce load to 80% of maximum load of free-rolling application.

Load Bonus Table – D Speed Implement Tyres

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For D speed implement tyres, load carrying capacity for Free rolling and Drive wheel application are the same (same load index applies).

Load Bonus Table – Bias Ply Steer Tyres

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(1) Applies to 6 PR tyres and above.
Inflation pressure to be increased by 25%.
(2) In case a front-end loader is fitted on the tractor, 100% overload is allowed, with a 25% increase in inflation pressure.

Load Bonus Table – Traction Tyres - Industrial Usage

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(1) One way distance 150 m.
(2) One way distance 600 m.

Load Bonus Table – MPT (Multi Purpose Tyres)

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TWIN TYRE LOADS = 2 x SINGLE TYRE LOADS

For 10 km/h and below increase the inflation pressure by 17%.
For use on special designed vehicles (firetrucks, garbage trucks, etc.) or for special uses (snow plowing etc.) and industrial vehicles, please contact your Tyre dealer.

Load Bonus Table – Skid Steer Tyres

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RIMS AND WHEELS

Tyres are moulded to fit a certain rim diameter, rim width and flange contour. A wheel essentially consists of two parts: the rim and the disc.

The rim receives the tyre. Its flanges keep the beads in place when the tyre is inflated. The two seats, usually inclined at 5 degrees to improve the fitting, can be either smooth or knurled (which avoids tyre slippage on the rim). The drop centre is needed to enable mounting and dismounting of the tyre and its shape reinforces the rim structure.

The disc permits the attachment of the wheel to the vehicle hub. Its configuration is dependent on the type of hub. The disc and the rim of the rear tractor tyre are usually welded or riveted together permanently. Certain wheel types however, have adjustable discs allowing variable wheel track widths dependent upon the implement used or the farm work required.

The major wheel parameters are:

  1. Drop centre.

  2. Disc.

  3. Hub contact face.

  4. Offset.

  5. Rim diameter.

  6. Rim width.

  7. Rim flange height.

  8. Valve hole.

  9. Hub/brake drum.

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Note : Rim diameters can only be accurately measured by means of a special ball tape.

RIM SIZE DESIGNATION

Example tractor rim W 14L x 20.

W = rim profile code (single well).
14 = rim width in inches.
L = flange height code*.
20 = rim diameter in inches.

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Example tractor rim DW 12 x 38.

DW = rim profile code (double well).
12 = rim width in inches.
38 = rim diameter in inches.

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LIQUID BALLASTING

The traction or pulling power which a tyre can exert is in proportion to the weight carried. The greater the load on the tyre, the more tractive power it can exert. To secure more traction and reduce slippage and treadwear, either cast iron ballasts can be added to the front and/or rear end of the vehicle or the inside of the wheels, or the tyres can be partly filled with a water calcium chloride solution or antifreeze to 75% of the tyre volume.

Where freezing temperatures never occur, plain water can be used, but the weight added will be about 20% less than calcium chloride solution. Where antifreeze protection is needed, use a mixture of calcium chloride and water. For easy reference, please consult the tables here after.

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See load and inflation table for water fill volume by tyre size. Example: 620/70R42 see load and inflation table; 75% water fill volume is 616 litres. For conditions up to -15 deg. C:

  • Water amount = 0.93 x 616 = 573 litre.
  • Ca CI amount = 0.17 x 616 = 105 kg.
  • Total additional weight = 573 + 105 = 678 kg.

Procedure for Filling and Removing the Solution

Mixing the solution:
Make sure the antifreeze and the water are well mixed. For a calcium chloride solution, prepare the calcium chloride into the water (never the water into the calcium chloride as considerable heat is generated in the mixing process). The solution should be allowed to cool to atmospheric temperature before pumping into the tyre.

Filling the tyre:

  • Jack up the wheel.
  • Replace the valve by a liquid fill type which allows the air to escape while water is filled.
  • Turn the tyre to bring up the valve to top position. A tyre fill rate of approx. 75% is achieved when water pours out of the valve in this position.
  • Connect a liquid fill valve to a pump or container or in the case of filling with plain water to a tap.
  • Hydroinflate the tyre.
  • Install a regular tyre pressure valve, rotate the tyre with valve at the bottom and release the jack.
  • Set final working pressure after the tyre is loaded using special air-water gauge.

Removing the liquid:

  • Jack up the tractor.
  • Turn wheel to bring valve into bottom position.
  • Remove the valve and completely evacuate the liquid.
  • Re-install valve and re-inflate tyre to recommended operating pressure.

Please note that a calcium chloride solution needs to be properly discarded.

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TYRE SAFETY

DO NOT
Never attempt to unseat the beads of an inflated tyre.

  • Never re-inflate a tyre that has run flat or was seriously underinflated without removing it and checking for tyre, tube or rim damage.
  • Never rework, weld, heat or braze rims. Whenever any work on rims has to be performed, make sure tyre is demounted first.
  • Never install tubes that have buckled or creased or use a tube in a tyre different from what is specified by the manufacturer.
  • Never exceed 2.5 bar (35 psi) inflation pressure for bead seating during tyre mounting.
  • Never try to fit a tyre to a rim that does not exactly match the rim diameter. Example: 15 inch & 15.3 inch must not be mixed.

DO
Always use specialized mounting and demounting tools as specified by tyre suppliers.

  • Always remove the valve core and housing and completely deflate the tyre before servicing.
  • Always inspect inside of tyre for loose cords, cuts, penetrating objects, or other carcass damage. Repairable damage should be repaired prior tube installation Tyres with non-reparable damage should be discarded.
  • Always inspect inside of tyre for dirt, liquids, or foreign material and remove this before inserting a tube.
  • Always use new valves and tubes in new tyres.
  • Always clean and inspect rim and check rim diameter corresponds to the tyre diameter.
  • Always lubricate with approved tyre mounting lubricant. Never use anti-freeze, silicon or petroleum-base lubricants.
  • Always use an extension hose with gauge and clip-on chuck so that operator can stand aside during inflation and be protected by an approved safety cage.
  • Always inspect valve cores for proper air retention. Replace damaged or leaky valves.
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WARNING
When seating the beads during the mounting, never inflate beyond 2.5 bar (35 psi).

If the beads have not seated by the time the air pressure reaches 2.5 bar (35psi), deflate the assembly, reposition the tyre on the rim, re-lubricate and re- inflate.

After seating the beads, adjust the inflation to the recommended pressure.

Allowing air pressure to build within the assembly in an attempt to seat the beads is a dangerous practice.

In seating beads, inflation beyond 2.5 bar (35 psi) pressure may break the bead (or even the rim) with explosive force sufficient to cause serious physical injury or death.

Inspect both sides of the tyre to be sure the beads are evenly seated. If not, completely deflate the tyre, unseat the beads and repeat the entire mounting procedure.

NOTE:
If either bead should fail to seat at 2.5 bar (35 psi) inflation, the tube may be pinched between the tyre bead and the rim, or something else is interfering with proper mounting. Do not increase inflation pressure to mount beads, but remove the valve core housing and completely deflate the tube. Break both beads loose from the rim, re-lubricate the tyre beads and the rim bead seat areas. Reinstall the valve core housing and repeat the inflation procedure.

SERVICE AND MAINTENANCE

1. Inflation Pressure 
The use of proper inflation pressure is the most important factor contributing to the satisfactory performance and maintenance of tractor and implement tyres. Correct inflation pressure can be determined by weighing the loaded axle (i.e. rear tractor axle with implement in raised position) and then referring to the load/inflation tables shown for the tyre size. All tables give load per tyre.

Underinflation
Can cause damage to the cord body of the tyre. The continued abnormal flexing of the tyre causes premature failure of the tyre carcass.

Overinflation
Should be avoided except for hillside ploughing and when the tractor is required to operate on hard surfaces for any length of time.

Check inflation Pressures Frequently
Inflation pressures should be checked regularly (at least every two weeks). For accurate inflation use a special low pressure gauge which should be checked for accuracy at least once a year. A special gauge is required for testing tyres filled with water or antifreeze solutions. To determine the true operating pressure for water inflated tyres; the valve should be at the bottom of the tyre. Tyres should be tested when they are cold and before the tractor is put into operation. A tyre that appears to have sufficient pressure when it is hot will be underinflated when it cools.

Road versus Field Applications
Road and field work require different inflation pressures. Make sure that all times, the inflation pressures are adjusted according to the work conditions.

2. Use of Recommended rims
The use of rims narrower than the recommended brings potential mounting problems because the rim shield or flange cover molded into most tyre designs tends to interfere with the seating of the tyre beads on a narrow rim.

Once mounted on a narrow rim, the tyre rim shield applies undue pressure on the rim flange, with possible tyre sidewall separation or premature rim failure at heel radius.

On a narrow rim the tread is rounded. As with overinflation tyre treadwear will be concentrated in the centre area of the tread and traction in the field will be reduced. Always use the recommend rim.

3. Spinning
Tractor tyres with insufficient wheel weights or excessive inflation pressure will wear the tread bars smooth or will snag and cut the bars when subjected to tyre spinning on abrasive surfaces.

Addition of weights, adjustment of inflation pressure to recommendations, decreasing of draft load and proper operation will remedy this condition.

4. Competent Repair
Tyres should be inspected for possible damage, particularly cuts or breaks that enter into or expose cords in the carcass.

Damaged tyres should be removed promptly from the wheel and sent to a reputable tractor tyre services station for full internal inspection and if possible permanent repairs.

5. Valve Damage
When valves are torn off the tubes, it indicates a slippage of the tyre bead on the rim or an improper centering of the valve rim.

Slippage of the tyre bead on the rim may be caused by:

  • Low inflation pressure.
  • Improper seating of the bead on the rim.
  • Excessive use of a lubricant on the bead or rim when mounting the tyre.
  • Run below tolerance.

6. Grease and oil
To avoid damage of the rubber, do not allow tyres to come into contact with grease or oil. After using the tractor in spraying operations, wash any chemicals from the tyres.

7. Tyre Construction Mixing Mixing radial and bias tyres on the same axle should be avoided at all times. It can lead to instability and cause mechanical damage. In certain countries this practice is even legally prohibited.

ROLLING CIRCUMFERENCE

Size Comparison (Inch to Metric)

BY TYRE SIZE
SIZEODRC
9.5R2410373129
11.2R2010012986
11.2R2411023320
11.2R2811883574
12.4R2010383132
12.4R2411403432
12.4R2812423733
12.4R3213484045
12.4R3614464334
13.6R2411943591
13.6R2812963892
13.6R3615004493
13.6R3815564658
14.9R2412373707
14.9R2612973895
14.9R2813444033
14.9R3013954183
15.5R3815654687
16.9R2413173921
16.9R2613704110
16.9R2814244269
16.9R3014704404
16.9R3415764717
16.9R3816765024
18.4R2614424322
18.4R3015444622
18.4R3416464923
18.4R3817445238
18.4R4218315507
20.8R3818355480
20.8R4219375781
200/70R166862043
240/65R167182152
240/70R167412220
260/65R167422221
260/70R167752315
260/70R208772633
260/80R209492845
270/75R3212253691
270/80R3613374033
270/85R5017335237
270/90R4616645024
270/95R3614184271
280/65R167752315
280/70R168072400
280/70R188492540
280/70R209092726
280/85R2410923271
280/85R2811903575
28LR2616074808
300/65R168072405
300/65R188492539
300/70R209582865
300/90R5018205495
320/70R209882950
320/70R2410923267
320/70R2811913582
320/85R2411473430
320/85R2812553764
320/90R4617425254
320/90R5018445564
340/65R189092711
340/65R209582865
340/85R2411883548
340/85R2812923872
340/85R3815564684
360/70R2010383119
360/70R2411513433
360/70R2812613786
380/70R2010783207
380/70R2411823552
SIZEODRC
380/70R2812923888
380/85R2412453713
380/85R2813504041
380/85R3014004196
380/90R4618475563
420/65R2010543143
420/65R2411553453
420/70R2412323714
420/70R2813444030
420/70R3013924177
420/85R2413243940
420/85R2814254258
420/85R3014764417
420/85R3415754723
420/85R3816755032
440/65R2010803217
440/65R2411953569
440/65R2812853852
460/85R3015444612
460/85R3416464930
460/85R3817505252
460/85R4218305502
480/65R2412203640
480/65R2813353997
480/70R2413153970
480/70R2814124264
480/70R3014844439
480/70R3415814745
480/70R3816825057
520/70R3416444927
520/70R3817515258
520/85R3818395507
520/85R4219385815
540/65R2413153914
540/65R2814154228
540/65R3014654381
540/65R3415684701
540/65R3816705016
540/75R2815004477
540/75R3416694995
580/70R3818395486
600/65R2814944452
600/65R3416454925
600/65R3817485244
600/70R3016024777
620/70R2815794696
620/70R4219355811
620/75R2615954715
620/75R3016925032
620/75R3418085400
650/65R3818395507
650/65R4219355805
650/75R3218155421
650/75R3418465515
650/75R3819415800
650/85R3820596147
7.50R168052400
7.50R188602572
710/65R3016865008
710/70R3819425802
710/70R4220436118
710/75R3419305744
750/50R2614244243
750/55R2614864420
750/65R2616364850
750/65R2616414850
800/65R3218205420
800/70R3820556132
900/50R4219465835
900/55R3218375485
900/60R3219325776
BY ROLLING CIRCUMFERENCE
SIZEODRC
200/70R166862043
240/65R167182152
240/70R167412220
260/65R167422221
260/70R167752315
280/65R167752315
280/70R168072400
7.50R168052400
300/65R168072405
300/65R188492539
280/70R188492540
7.50R188602572
260/70R208772633
340/65R189092711
280/70R209092726
260/80R209492845
300/70R209582865
340/65R209582865
320/70R209882950
11.2R2010012986
360/70R2010383119
9.5R2410373129
12.4R2010383132
420/65R2010543143
380/70R2010783207
440/65R2010803217
320/70R2410923267
280/85R2410923271
11.2R2411023320
320/85R2411473430
12.4R2411403432
360/70R2411513433
420/65R2411553453
340/85R2411883548
380/70R2411823552
440/65R2411953569
11.2R2811883574
280/85R2811903575
320/70R2811913582
13.6R2411943591
480/65R2412203640
270/75R3212253691
14.9R2412373707
380/85R2412453713
420/70R2412323714
12.4R2812423733
320/85R2812553764
360/70R2812613786
440/65R2812853852
340/85R2812923872
380/70R2812923888
13.6R2812963892
14.9R2612973895
540/65R2413153914
16.9R2413173921
420/85R2413243940
480/70R2413153970
480/65R2813353997
420/70R2813444030
14.9R2813444033
270/80R3613374033
380/85R2813504041
12.4R3213484045
16.9R2613704110
420/70R3013924177
14.9R3013954183
380/85R3014004196
540/65R2814154228
750/50R2614244243
420/85R2814254258
480/70R2814124264
SIZEODRC
16.9R2814244269
270/95R3614184271
18.4R2614424322
12.4R3614464334
540/65R3014654381
16.9R3014704404
420/85R3014764417
750/55R2614864420
480/70R3014844439
600/65R2814944452
540/75R2815004477
13.6R3615004493
460/85R3015444612
18.4R3015444622
13.6R3815564658
340/85R3815564684
15.5R3815654687
620/70R2815794696
540/65R3415684701
620/75R2615954715
16.9R3415764717
420/85R3415754723
480/70R3415814745
600/70R3016024777
28LR2616074808
750/65R2616364850
750/65R2616414850
18.4R3416464923
600/65R3416454925
520/70R3416444927
460/85R3416464930
540/75R3416694995
710/65R3016865008
540/65R3816705016
16.9R3816765024
270/90R4616645024
420/85R3816755032
620/75R3016925032
480/70R3816825057
270/85R5017335237
18.4R3817445238
600/65R3817485244
460/85R3817505252
320/90R4617425254
520/70R3817515258
620/75R3418085400
800/65R3218205420
650/75R3218155421
20.8R3818355480
900/55R3218375485
580/70R3818395486
300/90R5018205495
460/85R4218305502
18.4R4218315507
520/85R3818395507
650/65R3818395507
650/75R3418465515
380/90R4618475563
320/90R5018445564
710/75R3419305744
900/60R3219325776
20.8R4219375781
650/75R3819415800
710/70R3819425802
650/65R4219355805
620/70R4219355811
520/85R4219385815
900/50R4219465835
710/70R4220436118
800/70R3820556132
650/85R3820596147

Size Comparison (Inchto Metric)

Speed Normal
Standard
Normal Section
Sizes
Standard
Radial
95/90
series
85/80
series
75
series

70
series

65
series
60/55/50
series
330.....200/70R16..
340......240/65R16.
350.....240/70R16260/65R16.
360.....260/70R16280/65R16.
3907.50-167.50R16...280/70R16300/65R16.
4107.50-187.50R18...280/70R18300/65R18.
410......260/70R20.
425.....280/70R20340/65R18.
450...260/80R20.300/70R20340/65R20.
475.11.2R20...320/70R20..
500.9.5R24......
500.12.4R20...360/70R20420/65R20.
52511.2-2411.2R24.280/85R24.380/70R20440/65R20.
525.....320/70R24..
55012.4-2412.4R24.320/85R24.360/70R24420/65R24.
57511.2-2811.2R28.280/85R28.320/70R28..
57513.6-2413.6R24.340/85R24.380/70R24440/65R24.
60014.9-2414.9R24.380/85R24270/75R32420/70R24480/65R24.
60012.4-2812.4R28.320/85R28.360/70R28..
62513.6-2813.6R28.340/85R28.380/70R28440/65R28.
625.14.9R26......
62516.9-2416.9R24.420/85R24.480/70R24540/65R24.
65014.9-2814.9R28.270/80R36.420/70R28480/65R28.
650...380/85R28....
65012.4-3212.4R32......
650.16.9R26......
67514.9-3014.9R30.380/85R30.420/70R30..
675.16.9R28270/95R36420/85R28.480/70R28540/65R28750/50R26
67518.4-2618.4R26......
70012.4-3612.4R36......
70016.9-3016.9R30.420/85R30540/75R28480/70R30540/65R30750/55R26
700......600/65R28.
72513.6-3613.6R36......
72518.4-3018.4R30..460/85R30...
75013.6-3813.6R38..340/85R38...
750.15.5R38......
75016.9-3416.9R34.420/85R34.480/70R34540/65R34.
750....620/75R26620/70R28..
750.....600/70R30..
750.28LR26....750/65R26.
775.18.4R34.460/85R34.520/70R34600/65R34.
800.16.9R38270/90R46420/85R38540/75R34480/70R38540/65R38.
800....620/75R30.710/65R30.
825...270/85R50....
82518.4-3818.4R38320/90R46460/85R38.520/70R38600/65R38.
825....620/75R34...
825....650/75R32...
875.18.4R42300/90R50460/85R42....
875800/65R32.......
875.20.8R38.520/85R38.580/70R38650/65R38900/55R32
875..320/90R50.650/75R34...
875..380/90R46.....
925.20.8R42.520/85R42710/75R34620/70R42650/65R42900/60R32
925....650/75R38...
925.....710/70R38.900/50R42
975.....710/70R42..
975...650/85R38.800/70R38..

The table shows equivalents between crossply tyres, standard radial tyres, wide tyres and low pressure super wide/volume/super volume tyres.

Certain tractors have original tyre mountings where the front to rear axle ratio is close to the limit advised by the manufacturer. In this case we advise taking into account the tractor manufacturers recommendations.

The exact mechanical ratio “D” can be obtained from the manufacturer or dealer.

To check, we propose using this general formula:
[(Circumference *Front x D) – Circumference *Rear] x100
Circumference *Rear= X % Front axle lead
*Consult table of tyre rolling circumferences

According to the manufacturers of tractors, front axle lead should be between 0% and 6% but the most common is between 2% and 5%.