Tyres

The Super Single
The standard 'super single' 385/65R22.5 is a re-mould truck tyre as is the slightly wider 445/65R22.5. The tyre offers good road use but does not offer flotation in the field. For 9 tonne trailers there is the option of the smaller 340/80R18.

Cross-ply Flotation
This is a cost effective alternative to the super single. In general cross-ply tyres have a nylon carcass and are limited to a speed of 50km/h. The load capacity is also limited, compared to a radial flotation tyre. The standard option is normally 16ply which will be written on the sidewall. A number of cross-ply implement tyres with 14ply rating are fitted to smaller trailers and are restricted to a speed of 40km/h.

Radial Flotation Tyres
The majority of radial flotation tyres have a steel belt in the carcass which allows a higher pressure than most cross-ply tyres consequently higher load capacity. In addition they are normally rated to 65km/h and offer better performance on the road than a cross-ply tyre and better flotation properties as the carcass is more flexible providing a larger footprint.

The rule of thumb... if a customer has 50km/h tractors and is doing a lot of road work then offer the radial option - if the
tractors are 40km/h and an enclosed farm without a great deal of roadwork then cross-ply is an option.

Speed and Load Index (LI)
The Speed and Load Index give the manufacturer's maximum load and speed rating that the tyre is designed to operate within. The speed is designated by a letter and A8=40km/h, B=50km/h while D=65km/h. The Load Index is a number that when read off the Load Index chart provides the maximum load at the designated speed.

Tyre Description
560/60R22.5 - the 560 is the width in millimetres; the 60 is the profile or depth of side wall and in this example it is 60% of the width; the R indicates radial construction and if this is replaced with a dash (-) it indicates cross-ply construction; the 22.5 is the diameter of the wheel in inches.

Common Sizes and Load Index
Cross-ply
11.5/80-15.3 14ply 2430kg @ 40km/h
12.5/80-15.3 14ply 2650kg @ 40km/h
400/60-15.5 14ply (145A8) 3450kg @ 40km/h
550/45-22.5 16ply (156B) 3940kg @ 50km/h
500/60-22.5 16ply (159B) 4390kg @ 50km/h
550/60-22.5 16ply (162B) 4770kg @ 50km/h
Radial
560/45R22.5 152D 3550kg @65km/h
500/60R22.5 155D 3875kg @ 65km/h
560/60R22.5 161D 4625kg @ 65km/h
600/50R22.5 159D 4375kg @ 65km/h
650/50R22.5 163D 4875kg @ 65km/h
710/45R22.5 165D 5150kg @ 65km/h