TRACTOR TYRES REAR
TYRE SIZE ml TYRE SIZE ml
8.3-24 2000 15.5-25 5200
9-24 2500 15.5-28 5500
9.5-16 1500 15.5-30 6000
9.5-24 2600 15.5-35 5000
-32 3000 15.5-38 7000
-36 3300 16.5-16.1 4000
100-15 2300 16.9-14 4800
11-32 3000 -24 5500
11.2-24 3000 -26 5800
-28 3300 -28 5800
-34 3800 -30 6500
-35 4000 -34 6800
-36 4000 -38 7300
-38 4000 18.4-16A 6000
12.4-16 2800 18.4-26 6800
-24 3000 -28 7000
-26 4000 -30 7300
-28 4000 -34 7500
-32 4500 -38 8500
-36 4600 -42 9000
-38 5000 20.8-34 9000
-42 5500 -38 9000
13.6-24 4300 23.1-26 8000
-26 4300 -30 9000
-28 4500 -32 10000
-38 5500 -34 10500
13.7-28 4000 -35 11000
13.9-36 5300 24.5-32 11000
14.9-24 4800 26.5-25 10000
-26 5000 28.1-26 11000
-28 5300 30.5-32 14000
-30 5500    
-36 5800    
-38 6000    
15.3-38 6000    
15.5-28 6000    
       
JCB TYRES  OTR GRADER TYRES
TYRE SIZE  ml TYRE SIZE ml
8.25/15 3000 700-20 3000
900-16 3000 -24 4000
-20 3000 750-20 3000
10-5/80-18 5000 -24 4000
12.5/80-18 5000 825-20 4000
14.9/80-24 8000 900-24 5000
15.5/80-24 8000 1000-20 5000
12.0/75-18 5000 -24 6000
12.0/12.5-8 5000 1200-24 7500
12.5-18 5000 1300-24 8000
-20 5000 1400-20 7500
14.5R-20 6000 1400-24 9500
120-24 6000 1600-20 9000
15.5-25 8000 -24 10500
16.0/70-20 10000 1800-25 13000
16.5/85+24 10000 -26 13500
17.5LR-24 10000    
17.5-25 10000    
18.4/15-26 10000    
16.9/14-28 10000    
16.9-30 12000    
184-30 12000    
20.5-25 14000    

The JCB Tyre quantities should be adequate for all conditions.
If conditions is really bad used earthmoving quantities.
For OTR Tyres: If tyres are used in heavy puncture conditions-double quantities or more.