Fitting the wrong size of rowcrop tyres can be as bad as wearing the wrong size of shoes, warns Ron Wood, automotive engineering manager of CGS Tyres, the manufacturers of Mitas tyres. The wrong tyres can wear out more quickly and even cause transmission problems. Rowcrop tyres are especially prone to these issues, as they are constructed to meet the higher loadings and pressures that rowcrop- equipped units tend to carry, such as a large potato planter or heavy front and rear-mounted sprayer combination.
"We do see problems, especially when farmers try to carry heavier loads than their rowcrop tyres were meant for," confirms Eric Corrigan of specialist retailers Bush Tyres. "A lot of manufacturers have not caught up with the size of loads that rowcrop tyres need to be able to cope with".
Mitas will shortly offer one of the largest ranges of rowcrop tyres in the UK, combining eight sizes currently branded as Continental with five new Mitas tyres. Apart from the re-badging, the Continental tyres will be unchanged, as they will be made from the same mould in the same CGS factory. The new sizes are 270/95R32, 300/95R46, 320/85 R34, 320/90R50 and 320/90R54. "With 13 sizes in the premium quality rowcrop tyre bracket," says Jon Ward, Managing Director of CGS Tyres UK, "buyers gain both Mitas and Continental technologies in a dedicated range of rowcrop sizes, something often neglected by other major tyre brands."
Specific rowcrop tyre sizes offer higher load index ratings, and will therefore offer support to more weight than a similar ’standard’ type of tyre. With Mitas’
wide range, farmers can choose the right size - with higher load index ratings to match. With these higher specification tyres, greater loads at the correct pressure can be carried, resulting in greater tyre life expectancy.
Buyers also need to make sure that the front and rear tyre circumferences are compatible with the tractor’s inter-axle ratio - this is essential to prevent transmission problems. Generally, a conventional four-wheel drive tractor will have a ratio of around 1.2-1.3, but this depends on make, model and specification.
